Troubleshooting 101

Material for this blog post was originally presented on the Meriden Amateur Radio Club Tech Net, on August 20, 2020, a 2 meter net held on the first & third Thursdays of the month on the W1KKF, 147.360+ MHz repeater in Wallingford, CT, and simulcast on Zoom.

My love of amateur radio goes all the way back to childhood when I would waste hours in my grandfather’s workshop in our basement building Radio Shack Science Fair kits and mucking around with all the dead radio and TV carcasses he accumulated.  I have been melting solder for the better part of my life and to this day still love building kits and recapping, repairing and realigning vintage radios.

However, my skills have never been great…  I lack what many employers have rudely called an “attention to detail.”  All these years later, I’m sorry to say that still the majority of things I put together don’t initially work as they should. 

I used to get discouraged but then realized this was actually a gift – – – instead of abandoning a non-functional project, which would make it a waste of my time and money, I have discovered the process of troubleshooting actually gives me more bang for the buck. 

Troubleshooting requires a deeper dive in order to learn and understand how the circuit works which reinforces my electronics knowledge.  Finding and fixing a malfunctioning piece of equipment is also very satisfying and rewarding – it’s like solving a puzzle, but in the end you get something you can actually use. 

In this blog post, I’m going to cover some of the basics – including essential tools I use and the steps I take when tackling a new troubleshooting project. 

Disclaimer – I am by no means an expert, I believe I’ve made that clear. What follows is intended to be foundational and inspirational to others who have been frustrated when troubleshooting electronic appliances. More advanced techniques dealing with specific circuits is beyond the scope of this post. Look for future posts dealing with more advance RF troubleshooting topics.

THE ESSENTIAL BENCH TOOLS

The most basic tools you will need for troubleshooting include:

  • A good stable bench power supply
    You might be surprised the number of electronic problems are due to no or insufficient juice, reversed polarity and blown fuses.
  • A quality Volt-Ohm-Meter (multimeter) is essential for measuring voltages, current and resistance values. Today the majority of meters are digital and there are many serviceable units to be had for an inexpensive price.
    A good workbench should have both digital and analog meters. Analog meters still have an edge over a digital meter in certain circumstances such as when reading fluctuating signals (current), as digital meters typically give you an average reading. This is an advantage when trying to peak a tunable circuit.
Essential to every workbench today – magnification tools.

  • Good magnification is essential for troubleshooting, especially when working with today’s miniscule parts and circuit boards with surface mount components. Either a good magnifying desk lamp, or a plug-and-play USB Microscope that plugs into your computer is going to be invaluable. Like very one else who has made it to middle age, I have experienced waning vision (which pretty much sucked since ever since I started wearing glasses at age 2), and dexterity. I got my magnifying desk lamp on Amazon and my USB microscope from QuickSilver Radio, a favorite source for ham radio cables, small parts and tools.
    TECH TIP: In a pinch, your cell phone can be used to provide quick and dirty magnification. Simply use the camera to photograph the part you need to magnify then open the photo and zoom in – we are living in a Golden Age, my friends!
  • Temperature controlled soldering iron and tools. This is not an area to cut costs. Growing up I soldered with inexpensive solder irons from Radio Shack, seldom concerned with what their wattage ratings were – 15? 30? 45 watt? – Whatever it takes.
    I have learned in recent years the importance of a good temperature controlled solder station as well as the importance of using the correct iron tip for the application. This upgrade has been a game changer improving the quality of my solder work, while reducing my stress and frustration.
    It’s important to not use too much heat when working with delicate components and circuit boards, and it’s equally important to use too little heat when soldering joints.


TROUBLESHOOTING TIPS & TRICKS…. FIRST THINGS FIRST

The very first step in attempting to diagnose electronic equipment failure is to clearly define the problem., that is, what specifically is not working and also importantly, what else isn’t working?

Create a list of all symptoms and indicate whether the symptoms are intermittent. If intermittent, does the symptom occur when a specific control is activated? Does the problem stop if the appliance is moved or re-positioned? Once you have a list of symptoms and circumstances, evaluate the list – which symptoms might be linked? Where is there commonality to what is failing? Documenting and understanding all the symptoms can be useful.

The second thing to evaluate is the power situation. Technicians who do a lot of troubleshooting identify lack of power as the number one reason why a piece of equipment isn’t working. Sounds simple, but the question “Is the unit plugged in?” is foundational.

Make sure there is a fuse in the fuse holder, and that it isn’t blown. If it is blown, it will take more than just replacing the fuse, but you will know that something is awry with the power circuits – either a short or a failed component creating an overdraw of current.

Make sure that DC polarity is correct, and make sure there aren’t any broken power leads, disconnected power connectors, or cracks in the circuit board or broken traces around the power supply circuit.

After assessing the power supply, next up is an in depth visual inspection – this is where the magnifying tools come in handy. Carefully inspect both sides of the circuit board looking for obvious issues such as:

  • Missing components
  • Damaged/burnt out components
  • Broken traces
  • Cracked boards
  • Signs of previous ‘work
  • Obvious mods, parts replacements
  • Excess flux, solder blobs and cold joints
Some of the many problems to be discovered during a visual inspection.

TIME FOR THE DEEPER DIVE

If your circuit is getting proper power and you didn’t find any obvious problems after a thorough visual inspection, it’s time for the deeper dive. This will involve gathering, reading and understanding all the circuit documentation you can get a hold of. This documentation includes:

  • Schematic Diagrams
  • Block Diagrams
  • Chassis and Parts Layout
  • Manufacturer Manuals and Supplements
  • Third Party Manuals ( e.g. Riders, SAMS PhotoFact)
  • Component Data Sheets

The internet makes so much information available to the troubleshooter, most of it free. These resources include You Tube and online forums. (QRZ, Yahoo, Google groups, RadioMuseum.org), various manufacturer websites, and instructional sites such as All About Circuits.

Don’t forget about local resources, namely your local amateur radio club where you will find numerous older and wizened “Elmers” who are generally happy to pass on their expertise.

My local amateur radio club, The Meriden Amateur Radio Club here in Connecticut runs an open house every Saturday morning at the Wallingford EOC where we are headquartered. The open house features a repair bench staffed by the likes of NZ1J, Dave, KE1AU, Bob, and WB1GYZ, also Bob, who are always up for a new challenge.

Saturday open house workbench activities at the Meriden Amateur Radio Club


WHAT’S CURRENTLY ON THE AB1DQ WORKBENCH?
(a troubleshooting case study currently in progress!)

Earlier this summer I constructed the MFJ 9340 40 meter QRP Cub Transceiver kit. This kit was not unlike many others I have built in the past including the WA3RNX 40 meter transceiver, and the Wilderness Radio SST 20 meter transceiver kit. The MFJ kit came with a circuit board pre-populated with all of the SMD components and required the builder to install the traditional through the hole parts.

Construction went smoothly over two or three evenings and I was happy to find that I had no ‘spare parts.’ (A good sign.) I was able to align the receiver easily per the directions in the construction manual, however when I attempted the transmitter alignment, I ran into trouble. What happened?

I started troubleshooting with a good visual inspection focusing particularly on the solder side of the board looking for bridged solder joints. Nothing looked suspect.

Because this was a kit radio, I had just about all the documentation I needed in the manual to start trouble shooting including the Block and Schematic Diagram, a diagram of component lay out, and a page of Troubleshooting Tips too.

I started with these diagrams and breaking the radio down into separate functions and began color-coding the schematic, block diagram and parts layout. This took a bit of time, and you could argue it wouldn’t be necessary for a simple transceiver, but doing so did provide me with a solid understanding of how the radio was designed and where I can set my focus for finding trouble….

My color coded block diagram of the MFJ 9340 which ties to…

…my color coded schematic, which also ties to…

…my color coded Parts Layout.


Alan, W2AEW, provides a fabulous walk through of the 9340 circuit on his YouTube channel, which contributed bigly to make short-work of my color-coding work.

So now I know where the sub-assemblies and their parts are located on the circuit board, and I can trace the stages of the circuitry on the schematic, great! Now I need to go even deeper to see if I can find where the problem is originating.

The MFJ documentation had a table of voltages for each of the transistors and ICs. I am always thrilled when I can find a voltage table like this or see that proper voltages are indicated on a schematic.

I created a simple Excel spreadsheet with the MFJ data and carefully measuring the test points on my radio, I was able to calculate unit and percentage variances which allowed me to find trouble spots.

My Excel Table of specified voltages vs. my measured voltages.


I quickly identified hat the biggest variances were found on Q6, the Transmitter Driver, U5 the Transmitter Oscillator chip and Q5 the Transmit buffer. None of that was a surprise since I knew my problem involved the TX function.

However, I also observed a sizable variance on the BFO buffer, Q4, which might be related…


[SLIDE 16] I marked the over/under voltage readings on my schematic and cross referenced the parts layout to determine where I needed to focus. These parts were pre-installed, so I worked backwards from each in the circuit to look closer for problems.

Red indicates where the under-voltages are occurring…

WHAT’S NEXT AND SOME KEY TAKEAWAYS

This may seem like a strange place to end a blog post, but as of the time this material was presented on the MARC Tech Net on August 20, 2020, I had not yet finished my troubleshooting work on the MFJ Cub.

Next steps on the project will be to trace back ‘upstream’ from the variances on the schematic and closely examine my work, verifying that I placed the proper components where they belonged, and that my solder joints are good – not cold, and not blobby and bridged. I also want to take a close look on the two torrid inductors in the TX filter, L10 and L11.

While I had hoped and planned to have completed my work on the Cub prior to the net, I was unable to, and that’s my final lesson for now.

When troubleshooting, don’t rush and don’t get aggravated. Take it slow, work methodically and logically. Never jump to conclusions at the first sign of something unusual too. Many times the problem isn’t obvious and many times too, it’s not complicated. Stick to it and in the end you will find yourself rewarded with a satisfied sense of accomplishment.

As for me, I will update my blog when I have discovered and resolved the problem with the MFJ 9340. Watch for that post, or feel free to shoot me an email if you have questions, suggestions or want to discuss further.

GENERAL TROUBLESHOOTING TIPS

I mentioned that this material was originally presented during a 2 meter net. I want to thank the following stations who checked into the net, and I will close with some bulleted advise, tips and tricks that were shared by the participants…

STATIONS PARTICIPATING IN THE 2M NET:

W1EDX, N1ZN, K1RCT, KC1KQH, N1LES, N1KGY, N1AKN, N1GNV, N1BRL, K1LHO, K1JKF, KC1LGA, WB1GYZ, KE1AU, W1DQ, W1YSM

SOME COLLECTIVE WISDOM:

  • When testing a circuit, be careful with the test probes so you don’t create shorts. (N1ZN)
  • Keep your focus simple, look for the low hanging fruit. (K1RCT)
  • The problem is usually something basic and straightforward, and will more often then not involve the power supply (N1GNV)
  • Use the proper equipment when troubleshooting – you can easily destroy a circuit by using too powerful of a heat gun, or solder iron. (N1LES)
  • Proper calibration of test equipment is essential. (N1KGY)
  • High spec. test equipment with proper test ranges is important to have (N1AKN)
  • Google can be an outstanding resource for just about anything technological from cars to electronics. (N1AKN)
  • When working with an old dusty chassis, take it out to the garage and reverse the shop vac to give the gear a good blow-out. (N1BRL)
  • Be aware of high voltages and take proper precautions including shorting out capacitors before poking around. (KE1AU)
  • Work slowly, methodically and logically. Don’t expect a quick resolution and don’t set false deadlines to complete your work. (AB1DQ)


©2020 AB1DQ, James M. Surprenant and all others as cited.

Rectifying Laurence’s RECTifier woes…

This past winter, my old high school buddy, who we shall call “Laurence” handed off to me his Zenith Model G724 radio, a nice 1950 Bakelite case table top AM/FM superhet. According to Larry, the radio played well but had a broken dial string.

Dial strings can easily be replaced using common twine, and while I had the radio apart, it made good sense to replace the old wax and electrolytic capacitors and to test the tubes – simple basic maintenance to keep this radio working.

This radio has a selenium rectifier to convert AC to DC [Figure F, below]. While I was aware that selenium rectifiers are prone to failure as they age, I have never experienced a failure – most of the radios I have serviced feature tube rectifiers.

Laurence had shared my Facebook post about the service I had done to his radio on a vintage radio forum where an astute member spotted the selenium rectifier and asked if I planned to swap it out for a diode.

I decided I needed to broaden my knowledge of selenium rectifiers and what happens when they do fail. I came across two useful YouTube videos from two content providers I already subscribed to – Shango066 and All American Five Radio – that helped me fill my knowledge gap.

What I learned from both videos was that selenium rectifiers put out reduced voltage as they age, not delivering enough B+ voltage for the tubes. I also learned that if the selenium rectifier shorted out and overheated it would smell pretty awful and could cause more damage to the radio.

A modern general purpose rectifier diode, the 1N4007 can be used as a direct replacement for the selenium rectifier, however the selenium rectifier has a higher internal resistance than the 1N4007 which means a dropping resistor needs to be added in series with the diode to prevent tube filaments from burning out due to too much voltage.

In order to determine the value of the dropping resistor, I consulted the Sam’s Photofact and studied the schematic and voltage notes to find a reference voltage. According to my documentation, the grid voltage on pin 5 should be 125 VDC+.

Using jumper cables I placed the 1N4007 in circuit with my Heathkit Resistance Subsitution Box in series and my Voltmeter connected to pin 5 of the 35B5.

With the resistance set to 33 ohms, the voltage on pin 5 was 124.9 volts. [Figure A., below]

Because the resistance substitution box was old, I wanted to check the resistance with my ohm meter – I discovered that the 33 ohm setting actually read at 39.1 ohms. [Figure B., below]

I chose a 36 ohm 1 watt resistor from my parts box for substitution and when I tested it with the ohm meter and it read 38.0 ohms. [Figure C., below]

I soldered the 36 ohm resistor in series with the 1N4007 diode and soldered it into circuit. [Figure D., above]

I then tested the voltage on pin 5 of 35B5 and found the substitution worked fine as the voltage reading was now 128.8 VDC+. [Figure E., above]

In the end, Laurence gets a tuned up Zenith and the next time I see him, I shall collect my friends and family fee – 2 snorts of Jack Daniels Whisky! 🙂

Please leave your comments on this site, or drop me a line at James@ab1dq.com!

My CW Academy Experience

I earned my first amateur radio license, the gateway Technician ticket, in March of 2002 at the age of 37. It had been a lifelong goal to become a ham radio operator every since the radio bug first bit back in the 1970s when I spent countless hours in my grandfather’s radio/TV workshop melting solder and into the early 1980s when C.B. radio was the craze and I first discovered the wonders of shortwave radio listening.

Had I pursued my dream in earnest back then, the entry level license I would have studied for would have been the Novice license, requiring me to pass both a written exam and a 5 word per minute Morse Code exam.  However, that era ended in 2000 when the FCC stopped issuing the Novice license.

In 2002 when I was first licensed [as KB1IAR], although I did not need to pass a Morse code exam for the Technician license, I did need to pass the 5 WPM Morse code exam along with a written exam in order to upgrade to General class ticket which brought with it coveted HF privileges.

I passed the 5 WPM Element 1 Morse code exam along with my Element 3 written exam to upgrade to General a few months after earning my Tech, and a little over a year later I passed Element 4 to earn my Amateur Extra class license.

In earlier times, a ham radio operator needed to pass a challenging 20 WPM Morse code exam to upgrade to Extra class. Many older hams who worked so hard to clear this hurdle back in their day continue to sneer at us 21st century Extra class licensees, referring to us as “Extra Lites” while bitching and moaning about how licensing exams have been dumbed-down.

In 2003 the International Telecommunications Union ended the international Morse code requirement for an amateur operator to qualify for transmitting privileges on frequencies below 30 MHz and in December 2006, the FCC retired the Element 1 exam, eliminated all Morse code testing for US amateur radio licensees.

In the nearly 15 years since the Morse code exam has been gone, you might expect to find the CW bands dead, but I’m happy to report that Morse code remains a very popular operating mode today as amateurs like me are still drawn to and enjoy using Morse. It turns out that sending and copying code is a fun and worthwhile pursuit and ham radio operators are continuing to learn and use the code, not because they have to, but because they want to!

So given that there is a hunger for hams who have no code expertise to learn code, I hear the same question in a variety of amateur radio communities – either local clubs or online – “What is the best way to learn Morse code?”

When I was studying the code years ago for my General upgrade, I listening to Morse Code instruction lessons on cassette on my Walkman. The ARRL recorded code lessons, which are still available on CD, did an adequate job of teaching me to memorize the 26 letters, 10 digits, and various pro-signs at the dreadfully slow 5 WPM – sufficient enough for me to pass my Element 1 exam.

While it helped me earn my license upgrade, those recorded lessons did little to prepare me for operating CW on air. For the next several years I looked for other tools to improve my Morse skills and up my speed. These included online tools and smart phone apps.

Then I discovered CW Academy, a three tier interactive Morse code instructional class offered by the CWops organization. The classes are offered in 3 levels – Basic, Intermediate and Advanced and are held online via conferencing software such as Zoom. You meet twice a week with your adviser and several of your peers peers who are more or less at the same level of ability.

Classes typically meet online for an hour two times a week over an eight week semester. The course requires students to commit themselves to the program and there is nightly homework assigned so that you learn by immersing yourself into CW.

Several tools are used for homework assignments including MorseRunner and RuffzXP – two excellent interactive apps that simulate CW contesting. Nightly homework assignments also included listening to recorded sample QSOs and short stories intended to aid in developing good head copy skills.

Tonight I completed the CWAI (Intermediate) level course, and in all honesty, this is the second time I have taken the second level CW Academy course. I believe the key to becoming a good CW operator is to constantly use your skills – on air ideally, but by listening to code whenever you can. The Intermediate level course focuses on head copy, something I have always struggled with, but am becoming better at.

Our instructor this semester was John, AJ1DM, a CWops member and a great teacher. John challenged us, his students, to come up with weekly GOTA (Get On The Air Goals) to challenge ourselves to do more on air with Morse code each week. The GOTA challenge was useful for me as I no longer feel intimidated by operating CW. I feel comfortable with my ability to copy and send at about 18 WPM, enough so that I don’t hesitate to answer any CQs I hear, and I’m also no longer shy about calling CQ myself.

John was assisted this semester by two assisting advisers, Tony VE2KM and Bruce N9WKE. Tony and Bruce presided over break out sessions and came up with copying and sending games, quizzes and challenges for us.

My fellow classmates this semester were Doug K4LSK, Pat AA0O, Steve KC1EJO, and John, AC2SG.

CWAI Zoom session led by John AJ1DM on 02/27/2020 discussing high speed paddles

I would highly recommend CW Academy for anyone who is serious about learning Morse Code and is willing to put the time in to do the work over a two month period. The classes are fun, the work is challenging, and the program absolutely works. And, did I mention? It’s FREE! CW Academy is a labor of love of the members of CWops who want to encourage and promote CW and to help us up-and-coming Morse cuckoos to develop good operating skills.

My interest in becoming a good CW operator is so I will be able to get the most out of operating the QRP radios I have built over the years. When operating low power, good copying and sending skills are much more critical. I think I’m getting there.

I place colored pins in the World Map in my ham radio shack – red represents phone contacts, yellow is for digital, and blue represents CW (Morse code contacts). At the start of this year, there wasn’t a single blue pin in Europe. I am making progress!

This past weekend I was leafing through my logbook and realized that everyone of my 2020 QSOs to date have been CW – I haven’t keyed the mic since last year!

Thank you CW Academy!

My certificate of completion proudly hangs in my shack and serves as an inspiration to continue pounding brass and improving my fist.

AB1DQ Hustler 6BTV Trap Vertical HF Antenna Installation

Introduction

After seeing my OCF Dipole and G5RV wire antennas repeatedly come down over the past 3 years I decided to try something different this fall.

My wire antennas, up around 60′, performed very well, when they stayed up, and I am forever grateful to Bill, W1KKF, who was willing to come out each year with his bow and arrow to shoot the lead lines into my trees.

Knowing that the tops of the trees tended to sway in the wind, I had incorporated strain relief into my subsequent installations by attaching either an inline spring or bungee cord between the antenna end insulator and the rope. Yet, despite these efforts, the antennas continued to come down. Two years ago was particularly brutal when a series of bad storms (including a tornado touching down just south of us) sent large limbs and entire trees crashing down along with my antennas.

So I spent a good bit of time this summer considering and researching alternatives. As all hams know, there is no one perfect antenna and every antennas is a compromise antenna. As a married ham, having an XYL adds an extra level of compromise – her sense of aesthetics. A vertical attached to the eaves like my friend Ed, W1YSM has, or a mighty tower and beam =like my friend John K1LYP has, were both non starters.

I eventually considered trying a ground mounted vertical antenna, complete with ground radials. Our property in Cheshire, CT, includes about 5 acres of wetland beyond our backyard which can’t be built upon. I figured that placing the antenna just beyond the edge of the yard among the trees would be help obscure it, thus making the XYL happy, and the damp ground would also contribute to making a good ground plane.

I first considered a non-resonant 43 foot vertical which seems to have been all the rage over the past decade or so among hams. However as the 43 foot vertical is non resonant on any band, it would require the use of a tuner. Most of the articles I read agreed that the optimum location of the tuner is at the base of the antenna. Such a tuner would add significant cost to the project and its something I was not familiar with.

I next considered the trapped multi-band vertical. I discussed the pros and cons with another trusted ham friend, Steve, K1SKL. Steve told me that his first antenna was a trapped vertical and he assured me it should work well if properly installed.

So after a little more reading and research, I decided to give it a try and ordered the Hustler 6BTV antenna which would get me on 10, 15, 20, 30, 40, and a narrow portion of 80 meters. At the present time (Fall 2019) the antenna alone costs $241, and once you start adding the ‘recommended’ accessories – the price adds up quickly.

In addition to the antenna itself, I purchased the following components, accessories and special tools:

  • Ground Radial Plate $75
  • Tilt Base Fold Over Kit $62
  • Tilt Base Wing Nuts $10
  • Direct Coax Feed Add On Kit: $30
  • JetLube Pure Copper Anti-Seize $18
  • 1000′ 14 AWG Copper Wire for ground radials $50
  • Radial Plate Wire Attachment Kits (2) $18
  • 200 Lawn Staples $32
  • Guying Kit $34
  • 4′ 4×4 pressurized wood post $13
  • 50 lb sacks of Quickcrete (2) $12
  • Post hole digger $37
  • Bow saw for cutting down interfering nearby tree limbs $10
  • 100′ LMR400 feedline $120

When you add in the miscellaneous small parts I needed (replacing hardware I damaged such as over-tightened hose clamps, I was in about $800 – wow, that equates to approximately at least a dozen over-priced pre-fabricated G5RV antennas!

Getting Started

My work on the vertical antenna installation started back in late September. I easily identified a good location about 20′ back into the wooded area behind the edge of the backyard where there was a small clearing bordered by some downed trees and rocks.

Digging the hole for the post wasn’t difficult. Using the post hole digger I bought from the Home Depot made for fairly easy work. I encountered some tricky roots along the way, but none too thick that I couldn’t hack through them. My hole ended up being about 28″ deep.

Setting the post with Quickcrete was a snap too. I started by adding about 2″ of crushed stone to the bottom of the hole for drainage and poured the Quickrete directly into the hole around the post, checking often to make sure it stayed level. Per the Quickcrete instructions I poured about a gallon and a half of water directly into the hole and again double-checked that the post remained level. The concrete set and the post was rock steady by the next morning.

The next step was to attach the DXEngineering radial plate about 2 inches above ground using a pair of lag bolts.

The radial plate has 60 pre-drilled holes to attach ground radials and it was my intent to put in all 60. My first weekend attaching radials, I installed the first 20 radials by crimping the loop connector to the end of the copper wire on site, bolting the loop to the ground plate, and then crawling away from the post, rolling the wire spool outwards, and tacking down the radial with lawn staples as I went. This turned out to be an exhausting way to work, but it did allow me to maximize the length of each of the first 20 radials to fit the space I was installing it, stopping when I encountered a rock, a tree, or downed tree trunk.

I had read that when installing a ground based vertical antenna, the length of the radials isn’t as important as the quantity of radials. For elevated installations it is more important to have radials cut to resonance for specific bands. My first 20 radials measured anywhere from 15′ to 30′ long.

The following weekend brought sub-freezing temperatures and a nasty head cold. So I spent my antenna time working indoors preparing the next 40 radials. These I cut to 15′ in length each, crimped the loop connector, and then coiled the radial carefully so they wouldn’t become tangled. The following weekend I as able to quickly install these radials much more quickly than the first 20.

A few of my crimping jobs failed, so I ended up settling for 50 radials and I subsequently ended up pulling another 3 or 4 from the loop connector when standing on the radials near the post. Next spring I plan to revisit the radials, adding the remaining 10 and repairing any that are damaged to get back up to 60. I will then add crushed stone around the base and covering the radials in order to provide some protection.

Once I was satisfied with the radials, the next step was to attach the tilt over mount to the 4×4 using another pair of lag bolts and the pivot point bolts and lock nuts that came with the antenna. I encountered some difficulty with the one of the nylon lock nuts and ended up having to take a trip to the local hardware store for a replacement.

Assembling the antenna

The following weekend I began assembling the antenna mast in the garage. Assembly was easy enough, however I managed to over-tighten two of the hose clamps that came with the antenna, so this meant another trip to my local hardware store.

Traps and mast components ready for installation, done in my garage

Once assembled, I carried the mast out to the base for mating. The 23′ length made it awkward to move, but it wasn’t heavy and actually felt pretty balanced in terms of weight distribution. I used a plastic lawn chair to support the top end of the mast while mating it to the base and then again when folding the antenna over for tuning.

Despite my best estimate of the space needed for the antenna to fold over, I didn’t properly account for 3 gnarly tree limbs that managed to snag the 80M whip when folding the mast over. I picked up a $10 bow saw at the Home Depot and was able to easily remedy this problem this past weekend.

Tuning the traps

The final task was to tune the antenna for each band which is done by loosening the hose clamp at the bottom of each of the traps and sliding the trap downward a bit to adjust for a lower SWR. After each adjustment, I needed to raise the antenna again, take another reading, and then repeat the process until the antenna was in tune for that band.

I used my Rig Expert AA30 antenna analyzer and per the DXEngineering instructions, I started with the 10M band and proceeded to adjust each band in order – 10M, 15M, 20M, 30M, 40M, 80M.

I was able to obtain SWR readings of under 2.0 across most of the bands, which was ‘good enough’ for me given the fact it was below freezing out this past Saturday with a forecast of snow coming. I wanted to be sure I could get on the air before winter fully set in and I planned to revisit the tuning come the warmer weather in springtime.

How does it work?

When I first tried the antenna on the air last Saturday, I was surprised to hear very few stations on 20 M and 40 M. My SWR readings taken at the radio in the shack were also much higher on all bands than observed at the antenna site. Most vexing of all was that I was getting an infinite SWR reading on 20 M! How was this possible???

I decided to not obsess and let the problem go for the night. I returned to the antenna early the next morning to recheck the tuning only to find that nearly all bands were still in tune. (30 M was a bit high in the lower portion of the band than I thought it was the previous day.)

Working logically and through a process of elimination, the next likely culprit would be the feedline. I had purchased a new 100′ run of LMR400 from Quicksilver Radio at the Nutmeg hamfest this fall I had planned to use with the new antenna, but that came up short. I connected it to my existing feedline which ran from the house, underground around the driveway and up to the berm where my previous wire antennas were located. Knowing the new LMR400 should be perfect, I decided to connect it to another 100′ run of coax to connect the antenna directly to the feed point on the house.

That seemed to do the trick.

On Air Success!

After changing out the feed line, I immediately noticed a huge difference on the air. First, there was a lot of activity on 20 M and 40 M, and the measured SWR at the rig was back down under 1.5 for both bands.

I worked KC5SCK in Georgia on 20 M who gave me a 59. My second contact on 20 M was with Belgian Special Event Station OR18TLS (HRH Princess Elisabeth’s 18th Birthday) who also gave me a 59. My next contact was with F5RAG in France who gave me a 55 signal report and my last contact that morning was on 40 M with K0BAK/VE2, a Parks On The Air activation of VE4920 in Quebec. This time my signal report was only 36.

I was relieved that the antenna was resonating and I was able to make contacts and I look forward to getting better acquainted with it in the winter months ahead.

The future and conclusion

When the weather warms next spring, I plan to revisit the installation for some touch up work. My to-do list includes replacing a few of the radials I damaged and installing the rest to get to the full planned set of 60. I also managed to bend one of the hinge bolts on the fold over base (something the instructions cautions you to be careful about) which will need to be replaced. Lastly, I will want to revisit the tuning of all bands.

Overall, this was a really fun project that consumed the better part of two months and in the end my antenna is performing as anticipated. I would recommend the Hustler trapped vertical for any ham who has the time, space and money to undertake the project. It is not a quick installation, nor is it inexpensive. But the project was manageable and even fun and the satisfaction of making contacts with an antenna I assembled can’t be beat.

Have you installed a Hustler trapped vertical? What was your experience like? Feel free to drop me a line at james@ab1dq.com.

Thanks for reading and following my blog!

73 de AB1DQ

James

Hustler 6BTV assembled and on the air at AB1DQ

Banggood Calculator DIY kit build

Have you discovered the wonder of shopping at Banggood or AliExpress? They are both something of a Chinese version of Amazon.com (in fact the Banggood logo is not at all unlike Amazon’s) – online superstores where you can buy a wide variety of products from electronics to clothes to sporting goods to cellphones to jewelry to automotive parts and so on.

The smiling Banggood and amazon logos
also feature similar color schemes

One can make several arguments – political, risk, quality – for not purchasing from Chinese online vendors, but I can think of two solid arguments why I enjoy shopping there – the wide selection and the low prices.

Both Banggood.com and AliExpress.com sell several DIY (do-it-yourself) electronic kits – such as radio receivers, MP3 players, test bench equipment, digital clocks, ham radio QRP kits and accessories, etc. The variety is fairly large, especially in comparison to what is available these days from US vendors.

When I was a young scrub, Radio Shack sold a popular line of P-Box (perf-box) kits and I pretty much built all of them including the one-tube AM receiver, the indoor/outdoor thermometer, the shortwave receiver, and the “GoofyLight.”

Several of the excellent Radio Shack P-Box kits available in the 1970s which got me started in electronic kit building. Check out the excellent Hack-A-Day page on the Radio Shack P-Box kit to learn more.

For the last couple of decades before they folded, Radio Shack did not offer electronic kits that required soldering and several other companies that produced DIY electronic kits, such as Heathkit and Ramsey Electronics have now too either gone out of business or no longer sell DIY kits.

While there are still some excellent smaller scale firms producing mostly ham radio oriented kits today (Four State QRP Group, QRPme, Elecraft), the easy availability to basic electronic kits, like the ones I enjoyed building as a child, doesn’t exist today.

Enter our Chinese Friends

In recent years I have purchased a few DIY electronic kits from Banggood and AliExpress. My experience has been mostly a good one – the kits are crazy cheap, but sometimes the quality of the parts has been marginal at best.

Another problem I have had building kits from China is reading the instructions. English instructions aren’t always included, and when they are the translations are horribly fractured.

The ability to read a schematic can be beneficial, but may not be enough. I have attempted to construct Chinese radio kits where the schematic did not match the PC board and/or the parts provided. I have also been been frustrated at times to find key identifiers for parts like transformers are identified only with Chinese characters on the schematic.

One interesting hack for dealing with a problem with color coded parts such as RF transformers, that I picked up from a shango066 YouTube video, is to reference the resistor color code chart that might be included the instructions. This makes it possible to identify the parts by the Chinese character for the color in order to correctly place transformers on the circuit board.

Resistor color code from a Chinese DIY radio kit becomes a veritable “Rosetta Stone” for dealing with other color coded components such as RF transformers :
1 = black, 2 = brown, 3 = red, 4 = orange, 5 = yellow, 6 = green, 7 = blue, 8 = violet, 9 = grey, 0 = white, 5% = gold, 10% = silver.

The Banggood Calculator

Speaking of resistor color codes, what initially attracted me to building this specific calculator kit is that I noticed on the Banggood website that the buttons on this calculator had the corresponding colors of the resistor color code.

The calculator has a mode that will calculate 4 band or 5 band resistor values by entering the color of the rings. (Yes I know that you can easily calculate resistance with the simple table, but this is sort of a cool novelty.)

The calculator has 3 other function modes – basic decimal arithmetic, voltage calculations for LEDs, and decimal-hexadecimal conversion.

I ponied up $13.66 USD and ordered the Geekcreit DIY Calculator Counter Kit Calculator Counter Kit Calculator DIY Kit LCD Multi-purpose Electronic Calculator Electronics Computing with Acrylic Case (yes, that’s the actual product name on the website) along with a few other items to get the total high enough so I could enjoy free shipping. My package arrived on what must have been a not-too-slow-boat-from-China about 2 weeks later.

The Build

One of the great things about this specific kit is that the printed instructions were very good overall and they also included a QR code and the URL for a very well done fully illustrated online step by step assembly guide.

The plated through PCB is well labeled. The soldering portion of the build involves installing five resistors, one disc capacitor, two transistors, two ICs and two diodes.
Soldering in all of the components took less than a half hour’s time. All parts were clearly labeled and the online guide pretty much guarantees error-free building. I chose to not use the IC socket and directly soldered the main chip to the board.
The 20 push buttons have four contacts each and I soldered them to the PCB in four column groups of five, tacking down one terminal for each button, then checking to see that it was flush to the board before soldering the remaining contacts The kit comes with 2 printed sheets of key labels which sandwich between a blue button and clear cap.
The two row LCD attaches to the main PCB via a 16 pin header strip.

The entire kit took less than 90 minutes to build and I encountered no problems along the way. I did use an ohm meter to confirm the values of the resistors before soldering them in place. The acrylic case went together fairly easily, although aligning the last three screws that hold the LCD in place required a little back pressure with my free hand.

SPARE PARTS – My kit was complete without any missing parts and the kitter (Geekcreit) gets big props for including a spare sheet of the the key labels along with spare parts for some of the pieces that typically fly from my fingers and get lost in the carpeting. I opted to not use the IC socket.

Overall this was an excellent project for a Sunday morning at the workbench and now I have a one of a kind calculator that I can take pride in having built myself.

The only criticism I have about the calculator is that in order to change the two CR2032 batteries, you have to disassemble pretty much the entire acrylic case as there is no battery door. As mentioned above, mounting the LCD screen was a bit fiddly so I hope the batteries exhibit a long enough life.

Overall I would recommend this basic kit for anyone who enjoys building such things.

Have you built any DIY electronic kits from a Chinese online retailer? If so, which ones and what have your experiences been? Please drop me a line at james@ab1dq.com.

©2019 JMSurprenant

My Field Day 2019

Every year on the fourth full weekend of June, the ARRL (American Radio Relay League) and the RAC (Radio Amateurs of Canada) sponsor Amateur Radio Field Day, when amateur radio operators all across North America practice emergency communications, operating either from outdoors stations they set up for the event using non-commercial power, or from Emergency Operations Centers (EOCs).

In addition to providing ham radio operators with the opportunity to practice operating in challenging conditions, Field Day is also an opportunity to give amateur radio greater exposure in the public eye as our sites are open to general public and many include a GOTA, or Get On The Air station where unlicensed persons can experience communicating on the ham bands with the help of a licensed operator.

I am a member of the Meriden Amateur Radio Club / Wallingford Amateur Radio Group. Since our club station is located in the Wallingford EOC at 143 Hope Hill Road, it makes good sense that we operate there as a class “F” (EOC) Field Day station.

This is the second time that I have participated in Field Day with the MARC/WARG folks, and once again I had a great experience. My ongoing amateur radio resolution for this year has been to work on improving my CW (Morse Code) skills and Field Day provided a great opportunity to practice my ‘fist’ as I signed up to take the graveyard CW shift from 2:00 – 6:00 am along with my friend K1STM, Anne.

Anne has been a licensed ham radio operator longer than I have been alive, and her CW skills are amazing. Not only can she copy Morse Code sent at a much faster speed than I can, she can also pick out the faintest Morse Code signals burried under the background noise that I completely miss!

K1STM doing the ‘search and pounce’ on 40 meters during the graveyard shift.

In preparation for the start of my 2 am shift this morning, I went to bed early last night (before the sun set!) and set an alarm for 1 am. Before turning in, I had the coffee maker programmed to brew a pot of coffee which I brought along in my trusty Stanley vacuum bottle.

Arriving at the Wallingford EOC around 1:30 am, I met up with KC1SA, Steve, who was wrapping up the prior shift. He walked me through some of the basics of operating the club’s Yaseu FT991A transceiver which is linked to the N1MM logging software and controlled by the shack PC.

Operating CW in a contest from a PC keyboard is pretty easy. The software allows for the easy transmission of several pre-recorded messages such as our club call sign, the basic Field Day exchange, etc.

This was my first opportunity to operate the Yaseu FT991A rig – I loved it.

I operated the first ninety minutes of our of shift and made 13 contacts on the 40 meter band between 2:00 and 3:30 am. The band was not crowded and most ops were sending at a speed I was comfortable copying at, right around 20 words per minute. I was able to work several stations on the west coast in Arizona, California, some in Florida and even one station in Hawaii.

Anne took over around 3:30 and she also made 13 contacts on 40 meters before our shift ended at 6:00 am. Anne is blind so she relied on me to log the contacts she made in the N1MM logging software. Instead of using the computer keyboard to transmit, Anne operated using the Bencher paddles.

By the time our shift was over, I was exhausted, but felt good about the work we did. We were rewarded with a feast of a breakfast that included omelets, pancakes and Chorizo. In addition to making contacts on the air, we hams really love to eat too. Last night at the EOC, John Bee, served his famous “road kill stew” – a MARC/WARG Field Day staple for years.


KB1MFU, John, prepared this scrumptious breakfast of omelets, pancakes and Chorizo! Hams love to eat – go figure!

After breakfast, I drove Anne home and then decided I would make a few additional contacts from my home station. I worked another dozen stations, mostly in the midwest, running 100 watts on 40 meters using my Kenwood TS2000 radio to my G5RV antenna.

W3MIE, the Crawford Amateur Radio Society calling CQ Field Dsy on 40 meters….
I worked them at 1256 UTC from my home QTH.

So, Field Day 2019 is done and I had a great time once again. Did you operate Field Day? Let me know how it went!

73 de AB1DQ
James

Special Event Celebrates 100 Years of WWV

Not only did WWV survive the latest federal budget, the station turns 100 this year. Here’s news of of related events including an open house, recognition ceremony and a Special Event station.

WS1SM Ham Radio Blog

WWV_QSL_Card

The National Institute of Standards and Technology Radio Station WWV will be celebrating its 100-year anniversary in October 2019. The oldest continuously operating radio station in the world deserves a
grand celebration.

The National Institute of Standards and Technology (NIST) and the Northern Colorado Amateur Radio Club (NCARC) have reached an agreement and are working together to organize the event.

NIST will focus on the plans for Tuesday, October 1, when they will host a recognition ceremony and an open house at the radio station north of Fort Collins.

NCARC will operate a special event amateur radio station, call sign WW0WWV, on the WWV property starting September 28, and going 24-hours a day through October 2. The goal is to make as many U.S. and world-wide contacts during the 120-hour period as possible, using multiple bands and multiple modes on at least 4 simultaneous transmitters. The effort will require hundreds…

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AB1DQ-QRP is on the air.

As I have previously blogged about in this space, my ham radio resolution for 2019 has been to get on the air and make contacts with the low-power or “QRP” kits – transmitters, receivers, transceivers, and accessories, that I have built.

Today I write to report that I have achieved my goal, having made my first two QRP contacts today with W1NVT in Vermont and N1QLL in Maine on 40 meters.

My station today consisted of:

AB1DQ QRP station on the air today.: The WA3RNC 40M transmitter is the yellow device on the left. Clockwise, above, is the MFJ 913 tuner, the 4S Antenna Tuner, and the VEC-201 CW keyer. To the right of all and behind the paddles is the speaker for the LM386 antenna. I built all equipment seen here excepting the wattmeter and the Vibroplex paddles.

QRP: What and why?

Operating QRP (ham radio slang for ‘low power’) is a distinct niche within the hobby. The generally accepted definition of what qualifies as QRP, is using a transmitter putting out 5 watts of radiated RF power, or less. By comparison, most commercial high frequency amateur radio transmitters today are capable of transmitting 100 watts. Many hams will use amplifiers to increase the 100 watts up to 1.5 kilo-watts. Operating high-power is known as QRO, as opposed to QRP.

QRP operations attracts tens of thousands of hams, including yours truly, but why? After all, conventional wisdom holds that more power = more contacts as a stronger single may be received further away and be easier to copy.

Speaking for myself, there are several factors that have attracted me to QRP. Here are the top five:

1.) Building and operating my own gear

Any regular reader of the AB1DQ.com blog will know that I love to melt solder, to build kits and home-brew projects, and to troubleshoot and repair vintage electronics.

It all began when as a child I would while away the hours in my grandfather’s workshop. As a younger man, Grampy had enrolled in the DeVry Institutes home radio & television repair course (originally known as the DeForest Course) and his workshop contained not only all of his text books and tools, but also a cornucopia of old radio an TV carcasses for me to ‘work’ on. (I let out more than my fair share of magic smoke in those days, and blew the house circuit breakers more than once!)

`This article from the July 1967 issue of Pop’Tronics, found in my grandfather’s workshop, first introduced me to the concept of QRP decades before I got my ham ticket.

Today when I am in my workshop, I feel a connection to my late grandfather, especially when I am using his vintage test equipment that I have restored and kept in service.

And, as magical as it is to have someone on the other side of the planet respond to a signal I transmitted using a commercial radio, it’s just that much more special when I hear my call sign coming back to me on a radio I built from scratch.

Amateur radio is the only citizen radio service sanctioned by the FCC that not only allows, but encourages, its licensees to build, modify and experiment with their own transmitters and QRP allows me to do just that.

2.) The challenge & satisfaction of using minimal power

Quoting the FCC rules §97.313 Transmitter power standards…
(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.

Because the communications I desire is any communication with another station using a transmitter I built myself, 5 watts is more than enough power to get the job done – and its going to provide me with plenty of fun

One S-unit, the minimal change in signal strength that is noticeable, is equal to 6 db. For one S-unit increase in gain you would need to quadruple your power output. To gain one S-unit from 5 watts output, you would have to go to 20 watts to increase your signal strength by 6 db.

K3WWP, a co-founder of the North American QRP CW club NAQCC has provided this handy table on his excellent website addressing the matter:

This suggests that all other factors being equal, an operator could expect his signal report to go from a very good 579 report to a perfectly copy-able 559 when running 5 watts vs. 100 watts barefoot.

What I know from first hand experience is that I have on occasion logged successful contacts on SSB from Connecticut all across the US to the west coast running 5 watts on my Kenwood TS2000. If I can make transcontinental contacts running QRP phone, it should be that much easier to do so with the narrower bandwidth needed for CW.

3.) QRP is inexpensive

A lot of hams get their General class ticket giving them access to the HF bands but then discover that commercial gear, can be cost-prohibitive.

The popular basic Icom IC-7300 currently retails for $1,099 and the bare-bones IC-718 (the very first HF radio I purchased back in 2002 when I was first licensed) costs $599 new today.

Compare those prices to the cost of my QRP station above…

The WA3RNC transceiver base model without the digital dial, retails for $99, the 4S Tuner retails for $53, the VEC201 CW keyer is $30 and the MFJ-813 QRP wattmeter costs for $40 new. That comes to under $220 for everything (sans paddles, power supply and antenna—all of which you would need to get on the air with either basic Icom radio above).

4.) QRP is portable

The small size of most QRP radios and equipment makes it ideal for portable operations, easily fitting in a backpack or suitcase. Many QRP operators enjoy taking their stations with them when they travel and operating from hilltops, campsites, or hotel rooms is very popular.

Although I have not yet done so, it is my desire and part of my 2019 radio resolution to go portable with my QRP station. This weekend I attended NEARfest in Deerfield NH as I do most years. The weather was a washout for the most part, but I did stop by the Quick Silver Radio table in the commercial building to address my need for portable power.

Proprietor John Bee, N1GNV, a good guy and fellow member of the Meriden Amateur Radio Club here in Connecticut, hooked me up with one of their new Hammo-PWR power boxes, which contains a 12 aH rechargeable battery in a compact water resistant ABS case and some PowerPole connectors.

The only piece I am now missing for my portable QRP operations is a very good portable antenna. In the coming weeks as the weather improves I plan to experiment first with my Buddi-Stick antenna as well as some wire antenna ideas including easily transported dipoles and end-fed wires – stay tuned to this space for updates!

5.) The QRP community is awesome

There are many excellent radio clubs dedicated exclusively to low power building and operating and I am a member of several of them.

QRP ARCI’s QRP Quarterly is one of the most fascinating and useful ham radio publications available today.

The QRP Amateur Radio Club International publishes my hands-down favorite ham radio magazine, the QRP Quarterly. I read every issues cover-to-cover as soon as it arrives as it is chock-full of excellent articles including technical pieces, equipment reviews, hints and kinks, and experiences of fellow QRPers.

The North American QRP CW Club is a dynamic club dedicated to the promotion of QRP operations. Each month the NAQCC operates a fun month-long on-air challenge and a sprint. There is no membership dues and the club also publishes an excellent online newsletter each month.

The QRP Club of New England is another fine local club to which I belong. The club holds a weekly CW net on 80 meters on Thursday nights and always presents well attended informational sessions and a buildathon at the Boxboro New England Hamfest each September. I really enjoy meeting other club members and melting some solder with them each year.

In conclusion…

For many years I have enjoyed building various QRP kits and feel I have learned a lot about radio fundamentals along the way.

Some of the many QRP transmitter and receiver kits I have assembled over the years.

This year I am finally venturing into going on the air with the radios and equipment I have built and the prospect of making contacts with homemade is very exciting.

I invite other QRP enthusiasts whether old timers, noobs like me, or prospective QRPers to write me at james@ab1dq.com to share their experiences.

Stay tuned for future blogs about my experiences and in the meantime,

72 de AB1DQ/QRP

©2019 JMSurprenant

Building the 4SQRP 4-S Tuner/Antenna Coupler

Following up on last week’s successful build of the Four State QRP Group TRF one transistor radio kit, The Murania, this Sunday I thought I would tackle the build of their 4S Antenna Tuner kit.

As I wrote in last week’s blog, I have been a long time fan of the great kits the 4SQRP Group develops and sells, so I was excited to tackle this project. My overall ham radio goal for the spring is to assemble and put a completely home-built portable QRP station on the air this spring, and the 4-S Tuner should prove to be an essential component of my station.

Like the Murania kit I built last week, the 4S Tuner was designed by NM0S, David Cripe, and both kits share several of the same features including “Pittsburgh construction” where the backside of the PCB doubles as the front panel, and a case that is cleverly assembled by soldering six pieces of PCB together.

Construction

The fist step in building the tuner is to construct the inductor which is mounted directly to the back of a rotary switch. For many folks, winding toroids can be a chore. I’ve messed them up myself several times in the past, but as a general rule, I don’t shy away from kits that require toroid windings.

I found that winding the 4S Tuner toroid was actually a pretty straight forward task. For one reason the toroid itself was large enough to manimpuate easily in my hands. Another factor that made the project easier was that the kit comes with BUSS wire instead of enameled wire which is difficult to create taps with as the insulation must completely removed at each tap… a fiddly prospect at best.

But best of all, because the toroid is mounted directly to the back of the rotary switch, “stitched together” if you will by the windings, the overall construction was very straight forward.

The instructions provide two options for the builder, whether to place maximum inductance at the first, “A” position on the rotary switch, or whether to place maximum inductance at the last, “L” lug. I chose the first method.

My completed inductor attached to rotary switch SW2 – building it was a piece of cake.

Once the inductor/switch assembly ws completed it was time to move on to attaching components to the PCB. The kit contains a nominal amount of parts – 6 resistors, 3 ceramic capacitors, 2 LEDs, 2 transistors, and 3 diodes.

“Pittsburgh” construction is sort of a large scale surface mount method where there are no holes and components are soldered directly to pads on the PCB. Pittsburgh native Joe Porter, W0MQY is credited with developing this construction method. and this is my second 4SQRP kit built in as many weeks using the Pittsburgh construction method. I have found it to be especially beneficial when removing components – desoldering is a snap and there is no need for a desolder pump or wick to remove solder from plated holes. In the case of the Murania last week, the ability to unsolder and swap out components made modifying and experimenting with the radio a true joy.

A minimum of components attached to the PCB using the Pittsburgh construction method made for easy assembly.

The next steps involved attaching the inductor, tuning caps, a FWD/REV DPDT switch and a pair of BNC connectors. The entire build took less than three hours and was a wonderful way to waste a blustery spring Sunday.

Theory of Operation

According to the documentation published on the 4SQRP website, “the circuit detects a mismatch of the antenna using a Wheatstone bridge-type detector.

“The transceiver drives R1, R2, and R3, three 47 ohm resistors, with the antenna forming the fourth leg of the bridge. If the antenna is 47 ohms the bridge is balanced, and the differential RF voltage between the two legs (between R1-R3 and R2-Antenna) is zero.

“The diode-capacitor circuit D1-C4 detects any differential RF voltage present and generates a negative DC voltage across the capacitor proportional to the amount of mismatch.

“The benefit of using a resistor bridge, as opposed to a more conventional transformer-type bridge, is that regardless of the impedance of the antenna, the worst VSWR ever seen by the transmitter while tuning up is 2:1. For QRP rigs without internal VSWR protection, this should prevent damage to the finals.

Schematic – another fine design by David Cripe, NM0S

How does it work?

You will need to stay tuned for my on air review. As I mentioned above, my overarching project for this spring/summer is to put a completely home build QRP station on the air and while several components have been built, I’m not quite there yet.

Future blog posts will describe some of the QRP transmitters, receivers and transceiver projects I have worked on.

Thanks for reading & 72 de AB1DQ!

©2019 JMSurprenantH