Category Archives: Radio Modifications

A 3D-printed cover for the Mountain Topper MTR-3B QRP transceiver

Many thanks to SWLing Post contributor, Eric McFadden (WD8RIF), who asks:

Thomas, what’s the orange thing on the MTR-3B in the last photo in your post about the Red Oxx Booty Boss? [see photo above]

Glad you asked, Eric! It’s a 3D-printed protective cover.

My daughters have been asking for a 3D printer since they’ve used them at Maker Faires, the Pisgah Astronomical Research Institute, and most recently the Huntsville Hamfest. Both of my girls love designing and creating things, so this year we got them one for their birthday.

After loads of research, I purchased a Creality Ender 3 Pro 3D from Amazon.com (affiliate link) for about $240 US. My daughters were thrilled when they unwrapped the box on their birthday to find a 3D printer inside! We spent the following morning assembling it, calibrating the print bed, and printing a sample file.

Like most, our first prints were fun, simple things we found on Thingiverse. The girls printed a Saturn V rocket, a cat, and an X-Wing fighter. Those prints gave us an opportunity to learn about slicing 3D files, building support structure, and proper bed calibration.

Covering the MTR-3B

When the printer arrived, I already had the Red Oxx Booty Boss on order and was assembling my field radio kit.

One concern I had about the MTR-3B (in any pack) was that the small band switches could catch on a zipper or pocket mesh and be damaged. I had read a few accounts of this happening to others.

The LnR Precision MTR-3B transceiver

I thought about keeping the MTR-3B in a thick poly bag, but I knew that wouldn’t offer a lot of protection for the switches. Out of curiosity, I searched Thingiverse hoping perhaps someone had designed a small case that could possibly house the MTR-3B.

To my surprise, I discovered an engineer actually designed a snap-on cover for the MTR series of radios. It was then a simple matter of downloading the file, slicing it, and setting it to print while I slept that night.

The next morning, I had a cover sitting on the printer bed.

I purchased a pack of multi-color PLA filament knowing it would give my girls an opportunity to play with color a bit. The printer was already loaded with bright orange filament which I thought would be brilliant for the MTR-3B.

Those of you familiar with 3D printing are probably aware that ABS would be a better, stronger material for the cover since the side clips are certainly the weak points of the structure. We haven’t ordered ABS filament yet, but I think the PLA will actually function well for a while–it’s sturdier than I anticipated. When we have ABS in the house, I’ll plan to re-print it.

I couldn’t be more pleased because the cover fits the MTR-3B like a glove and doesn’t add a lot of bulk to this pocket-size transceiver. It was also a great print for beginners.

And best of all, I know the front switches and buttons are well-protected in my field bag.

I’d like to thank Thingiverse designer CockpitBob for designing this little cover and sharing it!

We’re also super pleased with the Creality Ender 3 Pro 3D printer. Thanks to my friends who helped guide that purchase decision.

Care to share?

3D printers are incredibly useful tools for radio enthusiasts of all stripes. I’m still very new to this world, so I would love to hear about your 3D-printed radio projects. Besides this post, we’ve featured at least one in the past, but I’d love to share more.

Please comment or contact me if you’d like us to feature your 3D project!

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Andy builds a genius companion control display for the Yaesu FT-817 transceiver

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Many thanks to SWLing Post contributor, Andy Webster (G7UHN), who kindly shares the following guest post:

Yaesu FT-817 companion display

by Andy Webster (G7UHN)

Like so many I love getting out portable with my FT-817 but I do seem to spend so much of my operating time fiddling through the soft-keys because my most used functions (CW narrow filter, power and keyer settings to tune an ATU, A/B, A=B, etc.) are spread across different “pages” of the A,B,C assignments. Compared to the sublime experience of using my Elecraft K2 the FT-817 can be a little frustrating!

Last month, inspiration struck and I thought I could cobble together a small microcontroller and a little OLED display with some buttons to provide some extra soft-keys for the radio using the CAT serial port. Nothing particularly original here (I’ve seen articles of people using PICs for this purpose) but it seemed like a nice sized project for me to play with and build some experience doing PCBs (I’ve only done this once before at home). A little bit of discussion with Michael G0POT (FT-817 and SOTA guru), some Google searching and we were looking over KA7OEI’s excellent reference page (http://www.ka7oei.com/ft817_meow.html) and thinking about our favourite FT-817 commands…

As it happened I was lucky to have the right bits (Arduino Nano, small OLED display, buttons, prototype board and an 8-pin mini DIN cable) lying around the house to see “first light” from my FT-817’s serial port that evening. The Arduino Nano is a good place to start because it works at 5V so can work directly with the FT-817 levels on the ACC port. What followed next was some late nights of hacking on Arduino code to send and receive the data for my favourite commands and more experimentation on prototype board.

I tried a couple of cheap OLED displays and they look great indoors but weren’t quite up to the job in full sunlight which is fairly typical in my portable operations.

Daytime readability issues with an OLED display

By this point I had also realised the utility of having an auxiliary display on top of the radio as a much easier thing to view than the 817’s own display on the front panel. I’d also experienced some interference from the unshielded prototype board coming through as clicking sounds on the radio’s receiver so it looked as though some isolation between radio and my circuit might be necessary. Guided by many Internet tutorials, I switched to using a Nokia 5110-style LCD for better daylight readability and lower power consumption. Adding an ADUM1201 digital isolator and a B0505S-1W isolated DC-DC converter to the prototype board (modules acquired very quickly from eBay suppliers) gave me some isolation and lowered the interference which I guessed would disappear when I made the design on PCB with good ground planes around the signal lines.

Screen capture showing the schematic (click to enlarge)

With a (mostly) working prototype it was time to hammer the Internet tutorials again, this time to learn how to use KiCad, a free open-source PCB design tool available on Linux, Windows and Mac. I’ve done one PCB for home projects before using Autodesk EAGLE and I found learning Eagle pretty hard going, it seems like it carries 20 years worth of baggage and dogma in the user interface. In fact I started using EAGLE on this project but spent 3 hours on the first evening just trying to change the labels on the ADUM1201 chip that I couldn’t find in an EAGLE library… so I gave up and thought I’d try KiCad which I’d seen some recent good reports on. I’m happy to say after finding an excellent tutorial on KiCad I had drawn the schematic and my PCB layout in about 15 hours working time spread over a few evenings.

I should add that the 15 hours of KiCad time did include several hours of agonising over the choice of slide switch so a PCB can be done much quicker than that once you’ve got your favourite parts sorted!

That’s pretty impressive for my first go with KiCad as a near-beginner to PCBs, I heartily recommend it, it was so much easier than EAGLE and quite an enjoyable tool. Right, PCB design done and uploaded to JLCPCB for manufacture. 5 PCBs with DHL shipping cost me less than £20 and arrived from China within 5 calendar days. Other PCB fabs are available… 🙂

Click to enlarge

So that brings us to today, pretty much. The PCB was assembled very quickly (!) and there is no sign of noise from the serial data lines creeping into the 817’s receiver now it’s on PCB. Some lessons have been learned through the construction (e.g. brown 6mm push buttons are less “clicky” than the black ones and that’s a good thing!) and I now have my companion FT-817 display/buttons in field trials. I’ve no plans to sell this, it’s a trivially simple design, but it does make a great home project to polish your skills in microcontrollers, PCBs and construction. I’ll post a write-up on my website in due course.

In use, the device works just as I’d hoped, I can do everything I want to on my FT-817 without having to fiddle through the awkward button presses. The frequency display is also in a much better position for me now (as most FT-817 owners will know as they jealously eye the KX2, KX3, etc…!) and I think I used it for the whole session when I took it to the field on Saturday. If only my CW had been so slick!

Next steps are to work on the Arduino code. My code is pretty rubbish (my coding style involves a lot of Stack Overflow and copy/paste!) and not safe for public consumption. There are also some health warnings to be noted in manipulating the FT-817’s EEPROM (required for some of the functions I wanted), explained on KA7OEI’s page but there have been a few volunteers on Twitter to help with the software which is great. Also I may do a “Rev 2” board with an Arduino Pro Mini to lower the drain on the FT-817 battery before sharing the PCB files. Other than that it’s now time to get back outdoors and enjoy the new improved interface to my smallest radio! 😀

73
Andy G7UHN

Andy, I absolutely love this project! A wonderful addition to the FT-817/818 and I’d hardly call it a “trivial” design–!

I purchased the original FT-817 shortly after it was introduced. At the time, I was living in the UK and travelled extensively throughout Europe. I loved the ability to simply throw this little rig into my carryon and play radio pretty much anywhere my work travels took me. In the end, I did less ham radio work with the FT-817 and more SWLing.

Still, I eventually sold my FT-817 for the very same reason that motivated you to build a companion display: the front panel is too small and my most used functions require too much menu digging.

Your companion board is an elegant homebrew solution. I love the Nokia LCD screen–superb readability in the field.

Thank you again and once you do a write-up on for your website, we’ll be sure to link to it on the SWLing Post!

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Kostas’ Yaesu FRG-7 adjustment that improves opposite sideband rejection

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Many thanks to SWLing Post contributor, Kostas (SV3ORA), who shares the following video and writes:

In this 7.8Mb video (attached) is my solution for “converting” the Yaesu FRG-7 for single signal reception on SSB:

Not a mod actually, no additional filters, no soldering of any kind. Just tune the BFO on USB and on LSB a bit far away from the 455KHz ceramic filter (using the transformer for LSB and the capacitor for USB, as the manual states). As the video shows, this provides the near to
carrier selectivity to cut off the unwanted sideband.

The price you pay is more high frequencies (but in the wanted sideband) and a bit attenuated low frequencies as the filter is effectively shifted to higher frequencies. Very high frequencies cut-off is helped by the tone control of the receiver to some point.

This is a cost-free mod and requiring even no soldering skills, neither any mod to the receiver. Now as you tune the bands in SSB and CW, you do not hear the same signal twice. On AM mode nothing changes, since the BFO is switched off in this mode.

Many thanks for sharing this, Kostas! This seems like a simple adjustment for one of my all-time favorite receivers!

Post readers: Check out Kostas’ website for more modifications, ideas and radio projects.

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Radio Waves: ABC Wage Freeze, A Titanic Radio, FCC “Tweaks” LPFM Rules, and Digitizing a DX-160 Display

Radio Waves: Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers. To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Michael Bird, Dave Zantow, David Korchin, and Alokesh Gupta for the following tips:

ABC must freeze wages, government warns (The Guardian)

The Morrison government has put the national broadcaster on notice that it expects the ABC to embark on a six-month wage freeze to bring it in line with other taxpayer-funded agencies during the Covid-19 crisis.

The warning follows the government’s decision in early April to defer general wage increases for commonwealth public servants for six months. The public service commissioner followed up that directive by writing to all non-public service agencies – including the ABC – informing them the government expected them to adopt the same practice.

With no clear response from the ABC to the 9 April missive, Guardian Australia understands the communications minister Paul Fletcher wrote to the national broadcaster this week flagging his expectation that the organisation would defer a 2% increase for all employees scheduled to take effect in October under the ABC’s enterprise agreement.[…]

Radio used by the Titanic to call for help can be salvaged, judge rules (CNN)

A federal judge has ruled that RMS Titanic Inc. can salvage the radio used to call for help by the fated ocean liner after it struck an iceberg in 1912.

To get to the radio, divers would need to remove a part of the ship’s deckhand to reach the room known as the Marconi Suite, which houses the device.

The ruling modified an order issued on July 28, 2000, that said that RMS Titanic Inc. could not cut into the wreckage or detach any part of it.

Virginia’s eastern district court amended that order “for a unique opportunity to recover an artifact that will contribute to the legacy left by the indelible loss of the Titanic, those who survived and those who gave their lives in the sinking,” Judge Rebecca Beach Smith wrote.

Experts in the case testified to the “significant deterioration” in areas above and around the Marconi room, according to the document, and photos showed the “increasing breakdown” in the deck above the suite.

The suite, made of steel, consisted of three areas: sleeping accommodations, an operator’s room and the silent room that housed the radio. Each area was separated by wood walls that officials believe have dissolved, according to court documents.

The Marconi device and the artifacts associated with it face “significant threat of permanent loss,” the judge said in her approval of the expedition.[…]

FCC Tweaks LPFM Technical Rules (Radio World)

The FCC in April modified the technical rules covering low-power FM stations. It expanded the permissible use of directional antennas; permitted waivers of protections of television Channel 6 by a specific group of reserved channel stations; expanded the definition of minor change applications for LPFM stations; and allowed LPFM stations to own boosters. Read more about the changes here.

Michelle Bradley, founder of REC Networks, is an engineer and longtime LPFM advocate.

Radio World: What’s your overall assessment of the outcome and the scope of its impact in the LPFM community?

Michelle Bradley: While the FCC did not address three major issues that are impacting LPFM stations right now —the ability to address building penetration issues, the ability to reach “local” listeners in rural areas and the disparity in how LPFM stations protect FM translators vs. how translators protect LPFMs — the changes will benefit current LPFM stations by giving them more flexibility in moving locations, reduce the need for waivers and improve LPFM service in the southern border region. It will also open some additional opportunities for new LPFM stations in the next filing window.[…]

RadioShack Shortwave Goes Digital (Hackaday)

If you spent the 1970s obsessively browsing through the Radio Shack catalog, you probably remember the DX-160 shortwave receiver. You might have even had one. The radio looked suspiciously like the less expensive Eico of the same era, but it had that amazing-looking bandspread dial, instead of the Eico’s uncalibrated single turn knob number 1 to 10. Finding an exact frequency was an artful process of using both knobs, but [Frank] decided to refit his with a digital frequency display.

Even if you don’t have a DX-160, the techniques [Frank] uses are pretty applicable to old receivers like this. In this case, the radio is a single conversion superhet with a variable frequency oscillator (VFO), so you need only read that frequency and then add or subtract the IF before display. If you can find a place to tap the VFO without perturbing it too much, you should be able to pull the same stunt.

In this receiver’s heyday, this would have been a formidable project. Today, a cheap digital display will do fine.[…]

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You’ve Been Warned: Emilio just brought a Grundig Frankenradio to life–!

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Many thanks to SWLing Post contributor (and certified mad scientist), Emilio Ruiz, who writes:

Recently I was given a broken Grundig G8 Traveler II. This radio had an accident–the case, speaker, tuning knob, and volume controls were all broken or damaged.

I discovered that the tuning and volume controls are not potentiometers, they are a rotary encoders, so I substituted the tiny and broken original controls with rotary encoders (typically used for Arduino projects), but I needed to remove the 10 kiloohms resistor to work properly (only used the CLK, DT, and GND pins).

All materials were reused from other things, the result is like a “Frankenstein radio”.

The “telescopic” antenna is a tape measure/flexometer which was broken too. I replaced the original speaker (which I think was another impedance) with a proper 8 ohms speaker which produced low volume, so i decide add a Pam8403 amplifier module for best performance. The total current drain is 0.10 amp for a regular “loud” audio level.

So the Grundig Frankie is alive!!… It’s alive!!

Click here to view video in new window.

This is brilliant, Emilio! Although this radio is quite scary–and, let’s face it, “post-apocalyptic”–I think it’s absolutely amazing! I love the handle and the tape measure antenna. You, sir, are a mad scientist and I look forward to your next creation! (I’ll just take shelter first!) 🙂

Anyone else ever created a Frankenradio? Please comment!

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Video: Antonio’s Kenwood R-2000 Modifications

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Many thanks to SWLing Post contributor, Dan Robinson, who shares the following:

Antonio Fernandez, who is in Spain, posted this on the Extreme page. Very interesting R-2000 mods:

Major modifications are adjustable RF GAIN (using the former TONE control), BFO Pitch control (former AM Squelch, FM Squelch is retained) and DSP Audio filtering for SSB and CW. Internal DSP module is SOTABEAMS Laserbeam Filter Module. The former DIMMER and NB push switches are used for switching on (bypassing) the DSP module and bandwidth (CW, SSB) selection.

Click here to view on YouTube.

Those are brilliant modifications on a classic receiver! Thank you for sharing, Dan!

Check out more videos from Antonio Fernandez on his YouTube channel.

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Jesse’s DX-390/ATS-818 modifications

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Many thanks to SWLing Post contributor, Jesse (W9JES) who writes:

I’ve been busy enhancing my Radio Shack DX-390. I added an IF-Out jack for my SDR, changed out the light for a LED, added a latch circuit for the light switch, added static protection, and disabled auto-mute. My blog with full instructions is at www.w9jes.com

Thank you, Jesse! Here are links to the various modifications Jesse has documented:

Click here to check out Jesse’s website.

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