Interested in Ham PI Group?

Fellow hams,

At the fox hunt last weekend, one of the new hams, Nan (KN4GUM) asked if there were folks interested in radio + microcontrollers such as Raspberry Pi, BeagleBone (which Nan has experience with), and Arduino. I said I had done a little bit of non-radio work with Arduinos and was very interested in learning more about it and Raspberry Pi. I’ve also really enjoyed the virtual antenna build days we’ve had and would like to continue with something similar.

Would anyone else be interested in forming a “Ham Pi” group? We could meet virtually once a month on Saturday afternoons to spend about 30 minutes discussing our latest microcontroller projects and swap tips, and then work on projects with others for virtual company for about an hour. Once Covid is over, we could also start meeting in person, if desired. I am very interested in learning to make a Raspberry Pi based APRS igate, and Arduino-based beacons/foxes.

Let me know if you would be up for some Ham Pi!


Aurora (KN4VXB)

Bill, N8BR on the OCRA Monday Night 10M Net via Video Conference

Remember the HF phone patch that used to be commonplace in the ham shack years ago?  How about a video conference HF patch?  Or for that matter, flip a switch and it’s a video conference to VHF/UHF patch?

Bill, N8BR does not have an HF station at his QTH, but that did not stop him from listening to the net and Dan, KR4UB passing on his comments to the net.

Dan hosted a video conference and invited Bill to join the OCRA Monday Night 10M Net on 28.450 via video conference.  Ham station audio is fed into the computer running the video conference application. A simple switch of the video conference microphone device driver setting from the normally used Logitech HD camera microphone to the computer line-input brings the ham radio receiver audio and Dan’s Heil headset microphone audio into the video conference.

© 2024 photo by KR4UB, OCRA Inc

Much of the equipment used and shown below has origin in other usage and has morphed into a small home audio studio serving multiple purposes. This application is a good example of the versatility it can provide.

The video conference “audio patch” application demonstrated here might could be built using some of the audio interfacing devices found in today’s ham shack for computer sound card driven amateur radio communication modes. However, if undertaken getting the audio chain correct might still require use of external audio mixers, attenuators, and additional isolation and perhaps impedance matching transformers, and instrumentation to get the sound right.

W2IHY Technologies Equalizer Function

The ham radio connections in this setup uses a W2IHY Technologies Equalizer that has multiple microphone inputs, one used for the Heil Headset microphone and a second input is used for the video conference inbound audio feed.  The internal microphone amplifier gain is adjustable to ensure appropriate drive level to the selected ham transmitter with the output fed via an internal isolation transformer for RFI protection. The output is switch selectable to one of  two ham station transmitters, in this case a Yaesu 8900 VHF/UHF and the Elecraft K3s transceiver. The phone jack output is an outbound (ham transmitter mic input) audio monitor output that is also connected to one of the Roland Monitors as described below. The equalizer interconnection ports available for all audio outbound to the ham radios are shown below.


Roland CM-30 Studio Monitor Function

Two Roland CM-30 Mini-Cube Studio Monitors in an interconnected stereo link configuration provides multiple audio channel mixer inputs as shown below on the one of the two units. One of the CM-30 units is used for all inbound (video conference incoming audio & ham radio receiver audio) feed mixing. Outbound (ham transmitter microphone inputs & video conference outbound) audio is separately mixed in, permitting audio from all sources to be monitored on the Heil headset as a final control operator quality check. Roland, a major manufacturer of musical instruments and sound stage equipment describes the CM-30 as a multi-purpose portable mixing monitor for the home-studio and portable live monitoring onstage applications.



A Jensen two channel isolation transformer previously used in a home theatre application is used to provide RF & ground loop isolation between the ham station and computer audio connections.  Braid ground strapping bonds all equipment to the common station ground.

A recently added connection for the video conference audio output will permit that feed to be mixed into the Elecraft HF or the Yaesu VHF/UHF mic input so video conference folks have half-duplex two way audio communications and can join the rag chew. None of this will be automatic and will require the control operator to set up the “audio patch” and operate the PTT control, the same as was required by the FCC back in the days of “phone patch” operations.

Inbound, Outbound, Mixing, Attenuators, etc, etc

Does the above discussion of all the inbound, outbound, audio mixing sound like one giant circular loop?  Not surprising… Ever wonder why speakerphones, telephone handsets, cellphones, bluetooth headsets, hearing aids and now video/audio conferencing…. any accoustic environment where speakers and microphones are in close audio proximity doesn’t turn into an enormous squealing audio feed back loop?  You’ve probably heard that many times with public address systems. What’s the magic?  What invention took place and has been deployed in telephone systems from the beginning?  The telephone hybrid transformer, used in bidirectional audio paths where two audio directions are combined in to a single audio channel. This function is essential in today’s world of communication devices and typically done with digitial signal audio processing. The mixing and combining of audio paths described in the above setup had to be done in a way to avoid generating an audio feedback loop at several possible points in the circuit.  The bidirectional processing or half-duplexing of conference audio by a video conference service is also a necessary ingredient.

The Nearby HT / Repeater Echo Effect

You’ve probably have experienced this effect in ham gatherings when you transmit on with your HT into a repeater and someone close to you has their HT volume turned up on the same repeater you are using.  You’ll hear your own voice coming through being delayed in time or an outright audio feed back squeal occurring. The delayed audio echo effect is caused by an audio delay line in the repeater controller for the purpose of removing squelch noise bursts at the beginning and end of every transmission into the repeater and also for masking DTMF repeater control tones sent to the repeater.  The OCRA 442.150mHz repeater is programmed to use a 70 msec audio delay to accomplish the above purposes. Sounds short, but very disorienting to hear your own voice delayed in time as you try to speak!

The conference to repeater audio bridge described in this article can have similar echos in the video conference side when repeater radio transmissions are recirculated from radios in the video conference. Video conferences can be more vulnerable as downloaded video conference applications typically provide a microphone audio AGC (automatic gain control) that if checked will adjust your computer/conference device microphone gain on the fly to make all voices at the same level in the conference. This is a good thing for the conference, but stray radio audio can be problematic.

However, the effect can be totally eliminated by proper audio protocols being practiced by those in the video conference. Those procedures will be described in a separate article.

While the equipment used here may border on overkill, hopefully the above audio discussion explains the necessity and there are advantages especially in the ability to measure, set and monitor audio levels at the key points in the audio chain. Among other uses, this setup has been used for some years as the final over the air audio level checks before a newly built repeater is deployed to a difficult to reach site such as the OCRA 442.150 mHz repeater located high up on the TV tower.

The setup is also used for periodic repeater checks and troubleshooting when repeater problems have arisen. The computer can do extended VOX triggered recording of the repeater to catch intermittent problems and spectrographic analysis software can be helpful on certain types of repeater issues.

Useful Software for Proper Audio Setup

Two computer applications were used to adjust the audio levels for optimum quality. The first program called Spectrogram, used in a vast range of fields, was written many years ago by Richard Horne, an Electrical Engineer working for the U.S. Navy. The second program Goldwave, a professional digital audio application was used to analyze historic recordings of the Moon landing, including establishing the “missing word” from astronaut Neil Armstrong’s famous line.

In summary, the building of this setup has been heavily influenced by other audio interests & needs, but also by experience in building the OCRA repeaters for the last 20 years. Mentoring by Danny, K4ITL in the early days of repeater building taught what it takes to set up repeaters to have excellent audio quality.

Dan, KR4UB

Bug Refurb – Another Piece from the Old Novice Station

from Bruce, N1LN

Another piece of the old novice station finished today.   The bug is one that my long ago SK uncle, W2NAD, gave me after I first got my ticket.  Since then I modified it into a paddle to use with a keyer I built from the ARRL book, Understanding Amateur Radio.

Now about 56 years later, it is a bug again!

© 2024 photo by N1LN, OCRA Inc

I lost the original weights so I made one out of a large galvanized bolt.   I cut the head off with a hack saw, drilled it / tapped it and DONE!

© 2024 photo by N1LN, OCRA Inc

He also let me borrow his HQ-129X, which is why I purchased one to go with my DX60 / HG10 combo.


Polycomm (Obi) 202 as a shack telephone service solution

By Charles McComas KN4PTU

I like having a wired desk phone in my home office/radio shack for use during conference calls and long waits for tech support. The clarity and functionality of a landline desk phone is much better than the average cellular connection. Until the last few months this was handled quite well by a VPN connection to my employer’s Cisco VOIP system. After I retired, I started looking for a new solution. In a perfect world, I would have gotten a POTS (Plain Old Telephone Service) line, as the reliability of the old analog copper wire system is unmatched by the newer VOIP (Voice over Internet Protocol) telephone services. Unfortunately new POTS lines are not available and all telephone service providers are rapidly changing existing lines to VOIP.

Checking with AT&T, my current ISP (Internet Service Provider), it would cost me a $100 setup fee and around twenty dollars a month for a phone line. I have had great experiences with the knowledgeable AT&T technicians in the past but a $100 service call to plug in a patch cable is a bit steep.

In my net surfing I came across Obi, who makes a range of ATA (Analog Telephone Adaptors) devices and phones. I ordered an Obi, now Polycom Obi202 ATA  (Photo 1) as it has a second phone line port that I plan to use for the fax function on my multi-function printer.

Picture of the Polycom Obi202

(Photo 1) Polycom Obi202

The back of the unit (Photo 2) has the two phone line (RJ11) connectors, a USB port for future functionality and two RJ45 connectors, one for Internet in and one for Internet out.

Back of the Obi202 showing the connections

(Photo 2) Back of the unit.

I will be installing the device in my hallway coat/telecom closet (Photo 3).

Photo of the interior of the hallway closet, showing the AT&T fiber modem, and cables and equipement mounted on the walls above the coat rod.

(Photo 3) Telecom closet.

I used a piece of masking tape to make a template for the mounting slots (Photo 4).

A piece of masking tape on the back of the unit with marks on it to indicate were the mounting slots are located.

(Photo 4) Marking the mounting slots

I drew a level line with a torpedo level and stuck the tape to the line (Photo 5).

Template tape stuck to backer board following the level pencil line.

(Photo 5) Tape template and level line

Drilled the holes for the mounting screws (Provide your own) and screwed them in (Photo 6).

Installed mounting screws on the backer board

(Photo 6) Installed mounting screws

I connected the provided patch cable to an open Ethernet port on the AT&T modem (Photo 7).

Back of AT&T fiber modem, showing were the patch cable is attached

(Photo 7) Modem Ethernet ports.

and to the Internet in port on the device (Photo 8).

Ethernet patch cable connected to the Internet in port on the Obi 202

(Photo 8) Patch cable attached to the Obi 202

A four-wire phone cable with RJ11 connectors goes from the Phone 1 port on the unit to a surface mount block in the closet (Photo 9).

Single jack surface mount block with a RJ11 keystone connector with a phone line coming  from the Phone Line 1 port on the device.

(Photo 9) Telephone line cable connected to the surface mount block.

. The cable from the block is spliced into the house’s original telephone service cabling and provides a dial tone to every telephone outlet in the house.

Before installing the power supply, I mark it with a paint marker to identify what equipment it is used for and the output voltage (Photo 10).

Unit power supply with the purpose and output voltage marked on it.

(Photo 10) Power supply

This comes in handy later to match up equipment with a power supply or to clean out a drawer that is overflowing with old power supplies.

The power supply is connected to an open outlet on the server rack PDU (Power Distribution Unit) and to the device. We have power and blinking lights (Photo 11).

Obi 202 connected and powered up

(Photo 10) Connected and powered up.

An Aastra 480e, analog desk phone, is connected to the phone jack in my office. I have a dial tone and I dial the special number provided in the instruction and do a echo test (Photo 11).

Phone sitting on desk

(Photo 11) Desk phone in place.

The next step is to set up a account on Once you have done that, you start the setup for a new device. On the phone connected to the ATA, you dial the number provided on the setup page and the Obitalk back end server identifies the device and you will see the device listed on your account web page

With a Obitalk account you can call and talk to other Obitalk accounts for free, but to call outside of the Obitalk network you need to have a account with a VOIP service provider. Obitalk supports most of the major home and small office VOIP providers as well as Google Voice. I have used Google Voice since before the technology was bought by Google and have been satisfied with the service. Best of all it is free for calls in the U.S. and Canada. But if you think that Google already knows too much about your life, you can go with one of the other VOIP providers. Also a big Warning, 9-1-1 service does not work with Google Voice. However you can add 9-1-1 service from another provider to your setup in Obitalk and still use Google Voice. Another concern is what Google gives for free, can be taken away in an instant, so I would not use a free Google Voice account for a phone number that is tightly tied to your business or where you can’t take an outage for a day or two. If you pay for G suite, those worries are about nil as Voice is part of G suite

Since I used my Google account to set up my Obitalk account, it had already configuring the Polycom Obi 202 to work with Google Voice. I made a few selections on what phone line to use for inbound and outbound calls and that was it. Configuration took less than 10 minutes and the total time I spent on the installation was about a hour. Most of that time was bringing in and then putting up the tools I used to install the device in my closet. Voice quality is very good. Reliability is too soon to tell.

Inside of the closet with the completed installation on the right wall

(Photo 12) The finished installation

Great Time to Update the Hamshack

From Keith, W1KES

Last month, we repainted our bonus room, A.K.A. dad’s shack after 17 years. Additionally, we added new furniture and shelves. I have spent the last several weeks organizing and optimizing the space. My shack also serves as my home office, which has received more use this past week than the previous year. With kids out of school until mid-May, I plan to spend many hours working and “hamming” in my recently renovated space.




From the Land of Magic – Solar Panel Load Controller

From the Land of Magic! a high tech solar panel load controller, built for son Pete. You can see that the latest components and construction methods are employed.

There’s a differential amp that drives an Ebay PWM speed controller ($11) to load the panels to their max power voltage, regardless of the insolaton* level. A sample of the panel voltage is compared to a Zener reference to generate the control signal to the PWM unit.The load is a 4500W water heater element in a tank in front of his regular water heater. There are three 235W panels with 29.4 V max power voltage.

I had a great talk with a dealer recently. It seems that PV power is now cheaper than heating water directly with wet panels. Cheaper panels and good inverters seem to have made a big difference.

Wilson, W4BOH

insolation* No that’s not a mispillin’  Insolation‘ is the solar radiation (power/Unit Area) that reaches the earth’s surface, which average high sun is close to 1KW/square meter.

Controller Schematic

A Better Mouse Trap or is that a CW Key?

Well I’m quite familar snap! with the Victor mouse trap after a recent bout of mice invading the garage and building nice little nests in the heater air intakes of not just one but two cars.. little buggers!

But, Ken AC4RD’s use of said device plus a couple Fender guitar picks and a wine bottle cork brings a whole new meaning to home brew! Always thought those wine bottle corks had another great use.

Thanks, Ken!

© 2024 photo by Ken AC4RD, OCRA Inc

Sheltering in Place due to the Coronavirus?

and want to stay in touch with your ham friends?

Show your friends your latest pride and joy project or any field of interest you would like to share with your ham friends.

How? Send an email to with attached photos, or a link to the photos you wish to share,  a brief description and I’ll post it on the OCRA website.

Face to face OCRA Club, Volunteer Exam Sessions & Board Meetings are cancelled until further notice due to the Coronavirus pandemic.

However, On-the-Air meetings and videoconferencing meetings will be used as an alternative. Stay “tuned” to OCRA-DFMA Joint Email List

Dan, KR4UB

What is it?

Well lets see… a large open field, complete with shadow of another tower with 2 large beams (and climber down below)  A top-hat loaded 100′ tower for the 160m band that the owner plows in sixty-six 90 foot long radials for maximum performance.

Who else? Of course its the new N1LN 160m band antenna setup.

Kubota tractor with an attitude..

Plan to use an Inverter Generator or run your Field Day station from a generator?

Variable speed inverter based generators offer significant reduction in audible noise and fuel consumption. Most consumer quality, constant speed generators that typically run at 3600 rpm are noisy and consume much more fuel.

  • The small inverter generators are well suited for Field Day due to their lower acoustic noise profile, provided their AC output is filtered to eliminate RF noise typically occuring in the 80m band.
  • Using short AC cords with no filter on an inverter based generator still presents unacceptable noise on 80M.
  • With no filter, detectable noise on the 40m through 10m bands was not found with the Honda generator shown in the next article below.
  • The RF noise filter in the next article using 3 large 4″ OD Fair-rite mix 31 toroid cores has been proven in a series of EMI test configurations to be effective in eliminating inverter generator noise. The complete, enclosed filter including a GFCI outlet with in-use rated cover for outdoor use, costs around $150 to build.

The degree of interferenence to an 80m station from an inverter based generator & attached cord radiated RF noise coupling into the Field Day antenna will vary somewhat based on the station physical arrangement. The graphs below are the received signal into an 80M station antenna located up 55 feet in the air, with a 50 foot drop cord lying on the ground underneath a portion of the antenna that connects the generator to the load.

noise profile

© 2024 photo by KR4UB, OCRA Inc

Thinking about running your Field Day station directly off a generator and not using batteries?

There has been discussion of eliminating batteries all together (as the Field Day rules permit) and run the station on a small generator. Tests should be done before Field Day with the specific AC to DC power supply and generator to be used to determine if the fluctuating loads of a CW/SSB transmitter is going to cause deep fluctuations in generator engine speed.

Why would one care?  Most hams know that with synchronous (aka constant speed) generators the frequency output is determined by the speed the armature is rotating, and the number of poles in the armature.  What may not be known is that the raw voltage output of the generator winding varies proportionally with speed at which it passes through the magnetic field (aka armature rpm). That’s why all synchronous generators have a voltage regulator circuit that adjusts the other variable affecting voltage output, the strength of the magnetic field.  The question is how well in a consumer quality generator does the voltage regulator and, the mechanical engine speed governor handle wild fluctuations in electrical load.

Rather than using mechnical speed governors, commercial large scale generators use electronic throttle control systems for more precise control of engine speed by comparing generator output frequency to the throttle controller’s internal 60Hz frequency standard.

Rather than expose expensive radios and DC power supplies to such effects,  one fix could be to still use a battery or two in the 12VDC circuit to buffer the generator from the wildly fluctuating loads such as a CW transmitter.

A Power Line Filter for an Inverter Generator

Dan, KR4UB

After viewing a recent Youtube video posted by the American Radio Relay League, Inc ARRL youtube video regarding RF noise that can be generated by inverter based generators, I decided to do some testing of my inverter generator, a later model, slightly higher capacity unit compared to a Honda generator in the ARRL youtube video.

First Impressions

The RF noise characteristics of my eu2200i unit do not seem as pronounced as demonstrated in the ARRL video, although that could be due to test configuration differences. It was noticed in the video that their antenna was very low and close to the generators. The horizontal loop and dipole antennas at home used in this testing are at an approximate 55 foot height over the test area.

  • The only amateur band that had generator noise was 80 meters and was loud enough to be an issue for Field Day.
  • Reducing the generator load helps reduce radiated RF noise.
  • Using a shorter drop cord can help, but not enough to eliminate generator inverter radiated noise.

Line Filter Project

Given the club’s Field Day plans to run in a higher RF power output class with the associated higher battery draw, the two transmitters of the combined 10m/6m stations I help set up and operate will be especially demanding on the batteries. If the Honda inverter generator is to be used to recharge this station’s batteries, a fix is needed to eliminate the possibility of RF interference to nearby field day stations.

The first step of the project began with a conversation with Howie, WA4PSC ProAudio Engineering who stocks the Fair-Rite toroid cores, regarding the best choice of ferrite toroids. His recommendation was the Fair-Rite 4.0” OD x 1″ H mix 31 units, given the frequency range at issue and will permit larger spacing between turns for less capacitive coupling.

The test configuration consists of the Honda inverter generator, drop cord and the power load placed beneath my HF horizontal loop antenna located approximately 55’ overhead. It was also in the vicinity of a dipole antenna also at 55’ above ground. Noise was observed on an Elecraft K3s and a SDRPlay 1a SDR receiver both using the same antenna. All displays of received noise below are from the SDRPlay 1a SDRuno application.

The generator test load is a 1500 watt electric heater, connected to the generator by a 50’ long drop cord. Several orientations of the drop cord were tried and as expected, there is an observable difference in received radiated noise based on drop cord orientation.

© 2024 photo by KR4UB, OCRA Inc

Two filter configurations were tested using different toroid winding configurations, both using three of the Fair-Rite 4″ OD x 3″ ID x 1″ L 2631814002 toroids.

Toroid Configuration #1

Not knowing whether the preponderance of the Honda inverter generator noise was common mode or differential mode, the first test was with toroid #1 wound with both neutral and the hot lead in a common mode attenuation configuration and then toroids #2 & #3 used as follows. Toroid #2 was for neutral & ground, wound for differential mode attenuation and toroid #3 for the hot lead similarly wound for differential mode attenuation. This configuration was not very effective in reducing the observed noise.

Toroid Configuration #2

Not satisfied with the above result, the toroids were all rewound for common mode attenuation as shown below:

The hot and neutral lines are wound on two toroids “in series” and the ground wire which can also be driven by common mode noise is on a separate toroid.

The “missing” (or more widely spaced turns you see in the photo below (at the top & bottom of each toroid) were required for these 4″ OD toroids to fit in the 4″ deep box and permit the cover to go back on. As shown the larger 4” OD toroids permit wider spacing between the turns and thus reduce capacitive through coupling across the turns.

© 2024 photo by KR4UB, OCRA Inc

One detail on the unfinished design above will be to bring out a ground wire stud for connection to a ground rod to be located near the generator.

RF Noise Test Results

Using a real world 80m antenna as the test reference for radiated RF generator noise is not ideal in determining any absolute noise level reduction by the filter given the typical high 80M noise floor. But it does reflect the real world of a typical Field Day station setup.

The unfiltered RF noise of the generator driving a 1500 watt load via a 50’ drop cord is shown below in the bandscope display of my SDR receiver connected to the horizontal loop antenna. The display shows the frequencies (the repeating blue bands) and correlating waves of increased noise across the noise floor of the 80m band. Using AM detector mode, the noise is audibly loud; however in LSB detection mode the noise is not audibly loud, just a higher background impulse type sound. While there were some signals on the band, only one (the orange line) was strong enough to show above the elevated noise floor.

© 2024 photo by KR4UB, OCRA Inc

Below is a sweep of the ambient 80m noise level without the generator running and, ironically during a widespread AC power outage that occurred February 07, 2020. The amateur radio station is powered directly by a large battery bank and the computer for this testing is on a high quality (and very low generated noise) UPS designed for the commercial market sector.

© 2024 photo by KR4UB, OCRA Inc

To illustrate the effect of generator load or lack of, on radiated noise, the 80m radiated noise shown below is with the same configuration as the first chart, i.e. the 50 foot cord attached, no filter, and no electrical load on the generator.

© 2024 photo by KR4UB, OCRA Inc

Finally, the noise filter effectiveness of Toroid Configuration #2 is shown below. The measurement below is with the same 1500 watt load, connected through the 50 foot drop cord, but with the filter inserted at the generator as shown on the next page. Compared to the first chart with no filtering, none of the repeating blue bands and correlating waves of increased noise are present across the 80m spectrum. No interference was found on the 40m – 10m ham bands or adjacent frequency bands. The multi colored traces are 80m stations active during the measurement.

© 2024 photo by KR4UB, OCRA Inc

Throughout the test, care was taken to keep all connected equipment and the drop cord in the same physical configuration. Earlier testing showed drop cord orientation (and of course length) can make a considerable difference in results.

Filter at the grounded generator & 50 foot cord connecting the 1500 watt load

© 2024 photo by KR4UB, OCRA Inc

Final filter design

Below is the final design using toroid configuration #2, with a GFCI outlet and stud bolt connection for ground included. The stud bolt ground is connected to the GFCI electrical outlet ground and goes to the generator electrical outlet via the plug connected cable green wire. Per Honda documentation the outlet ground is internally connected to the generator frame components.

© 2024 photo by KR4UB, OCRA Inc

While test results show this filter to provide effective RF noise reduction with the Honda eu2200i inverter generator, other similar style inverter generators may present a different situation due to possible different power transistor technology and inverter switching rise times.

A postscript is an afterthought, thought of occurring after the letter has been written and signed.
In discussing this filter with a few folks the conversation tends to turn to why this or why not that. The first EMI solution that works may be expensive and may not be the only design solution. Such is the world of EMI. The filter I built works, but with the included GFCI and other parts, is a bit pricey, approaching $140.00.  Would the smaller less expensive 2.4″ OD ferrites do the job? Testing of a filter using 3 of the 2.4″ OD cores proved the smaller cores to be ineffective. This is most likely from capacitive coupling of the closer wire turn spacing forced by the smaller diameter cores, or perhaps the core cross sectional area yields a magnetic flux path just too small for the amount of RF energy to be absorbed at the lower HF frequencies. Perhaps using only two 4″ OD toroids (eliminating the separate green wire ground toroid) might work, but hasn’t been tested.

Time spent learning what others have learned is always a worthwhile endeavor. Howie, WA4PSC of  ProAudio Engineering also passed on some excellent references for further reading. Jim Brown K9YC’s 60 years in ham radio, vice chair of AES Standards Committee working group on EMC and extensive research in the pro audio world is an excellent reference source. Jim’s  59 page “summary” reference document is well worth spending the time on the details of rf filter design. The filter design in this article correllates well with information his document regarding filters for the lower HF bands; e.g.two cores “in series”… check! … seven or more turns per mix 31 core… check! and choking the green wire ground… check, no out of sequence turns on the core… check!  Jim’s other publications can be found here.

46 SDR frequency sweeps, involving a number of test configurations, variation in filter components & design and involving considerable time were performed on this project looking for a better magic bullet. It did confirm the filter design in this article performed superbly over a number of test configurations, but no magic bullets were found.

Morse Trainer Kit Build; What Happened, and What’s Next?

by Steve, KZ1X

At the OCRA meeting (14 Oct 2019) there was a group build session for assembling the K1EL Morse Tutor kit club project.

Of the 25 or so kits involved in the project, approximately 6 were completed prior to the meeting! Those are our eager builders, and we’re lucky to have folks like that here to learn from. So few areas have such a rich experienced resource these days.

Another approximately 13 kits were assembled at the event.

More than a few assemblers were first-time kit builders, so, they get a special shout-out, as do the several experienced mentors present whose help was invaluable.

Since the success rate for the kits was effectively 100%, we can move to discussion of an evaluation of the event, and some next steps.

To start … It did seem like the participants were fully engaged and either re-learning their assembly skills, or experiencing them for the first time. This is certainly a good thing!

It would be great to get some additional and candid feedback on what went well – and what could be improved for some possible future event like this. Please feel free to share here or via direct email.

Now that many people have these kits built and operating, what comes next?

Several things, in fact, come next.

Immediately, please try and familiarize yourself with the settings on the Morse Trainer units you built. Pay particular attention to the setting that lets you control the sound pitch (tone) of the sending. You will want/need to be able to change this.

Also, work on learning TO CLEARLY SEND the first four letters of the lessons: E, T, A and N. Don’t worry about speed, it’s the smoothness that’s important to get down pat.

If you need to hear what these letters should sound like, I will be ‘playing’ them on the air, just after the ARES nets on Saturday mornings.

Lastly, don’t forget to remove the power jumper on your Morse Tutor when not in use, since the battery will drain if left on. That would take a month or two, but, no sense in running the batteries down for no reason. Simply unplug the jumper from the two pins and then re-seat it on just one, so you won’t lose it.

After that …

    1. The intent has been all along to offer weekly Morse tutoring lessons over-the-air via the 442.150 repeater … and in fact these were originally intended to start around now. There have been several setbacks to this plan, delaying the rollout by multiple weeks. I ask forbearance, all successful ventures take more time than originally anticipated.
    2. Group study events … did anyone notice the special feature of this kit, which allows people to pair-off and send Morse to each other in small group settings? The kits have a common RCA type jack on them, and with a simple phono male-male cable (which the club has several of if you don’t) they can be connected directly together! The MOST productive way to learn Morse is to first master a handful of characters (that is the purpose of the over-the-air sessions), make up words using just those letters, then send the code to a partner for practice. Then, reverse the listener and sender. These study events can be as few as two people, or up to MANY, and should take about 20 minutes each. The only catch is that there needs to be someplace people can go and have a quiet place for the study session. We’re spread over a very wide geographic area so this becomes challenging to manage. In an ideal world, we’d all have a weekly lesson session, and nobody would miss one. More realistically, those sincerely interested in learning the code can work with a buddy, perhaps one closer by than further, and help each other out getting to learn all 26 letters, ten digits, and a few punctuation and prosign characters.
    3. Computer aided training … there is Morse tutorial available called G4FON (the call sign UK ham who originally came up with it) and it’s available for PC, Mac, tablets, phones, you name it.In the next week or two I will send more information about this software and how to set it up to complement the coming training sessions.

For now… here are some links, see if you can install this software in your favorite device, and please report all successes or any gotchas: for Windows Apple iOS Android OS


Steve KZ1X

Fall 2019 OCRA Club Construction Project

by Steve KZ1X

A few months ago I conducted an email ‘straw poll’ to gauge the interest in a club construction project.

It has been quite some time since the last such project.

The target date proposed for this project is the October 14, 2019 OCRA meeting.

This year’s idea was to build a very simple, but great quality and low cost Morse tutor keyer kit, and to back it up with over-the-air Morse lessons at some later date.


The interest level in the kit itself was rather high, approximately 21 persons, and then others responding in ways other than via email. Some persons responding are DFMA members, as the email went out on the joint mail reflector.

Perhaps half the responders expressed concern about their electronics assembly skills.

They either were interested but felt it might be too complicated, many have never done anything like this before, they lacked the tools, were worried about success, or how to troubleshoot, needed help, and so forth.

Morse classes

The interest level in the Morse lessons was also high, higher than I expected. Some people wanted to get more proficient at their existing Morse skills and others wanted to learn from scratch. Still others already have Morse skills but just wanted to build the little kit!

Addressing the Concerns

To address the kit building concerns, at least two and possibly several more assembly workstations will be set up at the OCRA club meeting site, which for this session could start 30 minutes earlier than normal. The extra time would allow for everyone who wanted to, to get a chance to assemble and test his or her keyer.

Plenty of experienced builders are in the club and plan to attend this meeting, so there will not be any shortage of assistance.

To make sure the vendor can get the kits out in time, do not wait until just days before the event to order yours!

Project FAQ

  • Who makes this kit?

A small New Hampshire firm headed up by K1EL, a very well known ham whose call is almost synonymous with Morse keyer accessories.

  • How do you get a kit?

Order it from the link below.

  • How much does it cost?

The price currently is $22 plus shipping. The vendor is selling the kits quite near his raw parts cost, to assure it stays popular among newcomers to Morse. Another product sold by the same vendor, with similar functionality, costs almost 5 times this price.

  • How long does it take to get the kit?

About 4 or 5 days, here in NC. It comes USPS.

  • What else do you need to make the kit work?

Three AA size alkaline cells.

  • What tools do I need?

It is best to have needle nose pliers, a small flush cutter, solder, and a temperature-controlled soldering station. These links are just high-quality suggestions, for those wishing to equip one’s own new workbench. There will be tools available at the club meeting.

  • How long does it take to build?

Between 15 – 45 minutes, depending on skill level, equipment, pace, etc.

  • Are there any surface-mount type parts in the kit?


  • What happens if it does not work?

That is not likely to happen, if you build yours at the club meeting there is a near zero chance to have this kit not work.

  • Can I get my kit and build it myself before the meeting?

Yes, of course, and then you can help others!

  • What do you get in the kit?

All the parts needed to make one complete keyer assembly, except for the AA cells.

The vendor also answers many of these questions, of course, including a complete description of what the keyer does.

Check out the kit web page at this URL:

Here is a picture of the box as it comes from the vendor, located in New Hampshire.

The keyboard and mouse are shown for scale.

Inside the small white box are the circuit board and a bag with the parts needed to assemble the unit.

Here is what the unpopulated circuit board looks like, as you get it. (Yes, the AA cell holder is already mechanically attached, but NOT soldered.)

The bottom side of this circuit board, where the soldering takes place, looks like this:

There are approximately 54 individual solder connections to make.

Here is the bag of parts:

and when assembled, it looks like this:

The assembly manual is available from the link above, and there is a button to click to place your order.

Please post any questions you may have to the OCRA-DFMA reflector.

Looking forward to the October 14, 2019 club meeting and the construction project.

Steve KZ1X

Point me in the right direction

Dan KR4UB accepted the satellite challenge for Field Day, a noble challenge indeed.  Aiding his effort, Dan reclaimed and repurposed available parts and materials to build an industrial strength satellite antenna boom…materials and instructions follow.  Nicely done Dan!

  • army surveyors tripod non magnetic construction, no ferrous metals added below to disturb compass reading.
  • left over 2″ PVC electrical conduit and elbow..
  • some ironwood strips inside the PVC to take the floppy/flexy out and balance out weight of antenna.
  • wood doweling, epoxy, brass screws to reinforce compass support elbow butt glue joint onto PVC elbow
  • good quality surveyor’s compass bought to rough out new boundaries when  purchasing adjoining land some years back
  • section of left over central vacuum cleaner return pipe (near perfect fit over PVC electrical pipe).. rotates for quick antenna polarization adjustment.
  • Brass  screws (where used) so no ferrous metal near compass
  • Arrow VHF/UHF gamma matched antenna. The foam covered handle fits perfectly inside the end of the 2″ dia PVC electrical conduit used as the boom.
  • powered by arm-strong…..

© 2024 photos by KR4UB, OCRA Inc