Tag Archives: Modifications

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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My Replacement Stand Journey for the Grundig G6 Aviator

 

Guest Post by Troy Riedel

I’ve mentioned here in the past that I am an astronomy hobbyist first, and an SWL hobbyist second (call SWL my cloudy nights hobby).

A couple of years ago my Grundig G6 suffered from the troublesome “sticky” body that afflicts all of the Grundig/Eton radios of that era.  I used the recommended cleaning agent as has been posted here (Purple Power) to remove the sticky residue.  It worked great – but I discovered one must be very careful using this cleaner.  Why?  Excess cleaner seeped into the crevices where the radio stand mounts, was not fully removed/dried, and the cleaner “ate” the nubs off that hold the radio stand in place.  The result: a broken radio stand!  Right Photo: you’ll see glue residue smeared on the broken stand – where I tried to make & glue new nubs and failed miserably.

Through my astronomy hobby, I discovered someone (Joel) who 3D prints some astronomical accessories.  After ordering & receiving three quality products, we established a friendly rapport.  I asked him if he knew of anyone who 3D printed and commercially sold radio stands.

He replied “No” – and frankly he wasn’t quite sure what I was referring to – but he essentially conveyed “if you supply me a photo and dimensions, I will gladly print one that you can try”.  Great news!

After supplying him a photo and supplying dimensions, Joel printed off a stand plus a spare and shipped it to me.  Unfortunately, it did not fit … the side nubs were simply too small.

I wrote-off the encounter as having been worth the nominal cost & effort.  But Joel was not ready to write this off!  He asked for more details re: why it didn’t fit (we designed the stand about .25mm too thin – a small tolerance but significant in that the stand simply would not fit – the nubs were too small at the thickness that was printed).  We consulted, both made recommendations, then Joel promptly 3D printed another stand (v.2) and mailed it to me.

The end result: it fits perfectly – works perfectly.  I now have a replacement G6 stand and I feel my little Grundig Aviator Buzz Aldrin Edition (note the astronomy connection) was now, once again, whole!

 

For those who’ve replaced radio stands before, the biggest obstacle is *not* breaking it when you try to insert it into the back of the radio.  A tried and true trick is to freeze the replacement stand, so it contracts very slightly (by the mm), and then insert it into the body of the radio.  The great thing about this stand: it is designed with a cut-out on each side.  This cut-out allows the stand to ever-so-slightly flex (better – and probably more safely – than the freezing trick). This design allowed me to safely and rather effortlessly insert the stand without fear of breaking it.  And the stand’s thickness is quite capable of supporting the weight of the radio (note: the plastic of the 3D printed stand is not quite as hard as the OEM stand but it is still more than capable of supporting the radio’s weight).

I’m sharing this because Joel has added the G6 stand to his little BuckeyeStargazer Web Store , for $10 – what a great deal for us suffering G6 folks with broken stands.

At this time, the Buckeye Stargazer only offers the G6 stand.  But, who knows?  Before I came along, he didn’t offer any stand.  You might be able to cajole Joel into prototyping another stand?  For that – you’d have to contact him directly to see if he were receptive to more experimentation.

So, thanks again to the Buckeye Stargazer!  It’s always nice to tie my two hobbies together: astronomy & shortwave radio.

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Jesse’s DX-390/ATS-818 modifications

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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Imre’s HanRongDa HRD-737 modification increases sensitivity

Many thanks to SWLing Post contributor, Imre Olajos, who writes:

Hi, HRD 737 lovers! I have a good news!

I  (became brave enough to) modify my HRD-737.

I tried reverse-engineering- but I gave up. No numbers on IC-s. I found specifications for the analog switches (one for each band ) and found information about the transistors around those analog switch IC-s. Nice, 1 GHz fT transistors, all surface mount, so I gave up that line.

I found an NPN SM transistor in a damaged TV remote. It is only a 300 MHz transistor but
I had no better than that, so I started to build a little antenna amplifier circuit, wide band and simple.

I lost a few SM capacitors during the soldering but I have plenty of those. So the 1/4 square inch circuit board was finished last week. I tested it with an external 3 volt battery and I found it good working. Today ( 07-27-2019 ) I opened up the HRD-737 and wired it into the radio.
The results are much better than I expected. The HDR-737 became a good shortwave radio!

When I touch the built in antenna by my finger, radio is sensing the touch and station comes in. This effect was not there before. Radio became more sensitive on CB band than my Realistic DX392.

I have a YouTube channel [in the following video/slideshow] and I will show you the little ugly but great working circuit in the radio:

Click here to view on YouTube.

Later on next week I will try to record some video of the shortwave reception and post up it on the same YouTube channel.

I am a shortwave lover since 50+ years and I will be very happy to share the good news with others. Now I can listen my Greek music on this little radio, on 9420 kHz. Yes, the radio became [more sensitive than I had hoped].

You can see my other shortwave radios on my YouTube channel too, Have fun and never give up the hope!

Many thanks, Imre, for sharing and documenting this modification. One of the lessons here, too, is that if you have an inexpensive radio like the HanRongDa HRD-737 and you feel tempted to try a modification, there’s little to lose. It’s not like modifying a $1000 transceiver–just dig into the little radio and give it a go. If you harm the radio, you’ve only invested $37 or so in the project. That’s a much better solution than letting it sit on a shelf collecting dust because it’s not sensitive enough! Well played, Imre!

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Tivdio V-115: Simple modification to abate internally-generated noise

Many thanks to SWLing Post contributor, Marc Thomas, who shares a link to this site which describes modifications to eliminate the Tivdio V-115’s internal noise.

In a nutshell, the author made two small mods:

  • Decouple the power/battery with an electrolytic capacitor of around 10uF soldered to the battery connector inside the radio (see photo above)
  • The author also grounded the speaker, but didn’t test to see if this alone had any positive impact

I could not find contact details for the author of this mod, so I hope they don’t mind the fact I shared it here on the SWLing Post.

Note that the Tivdio V-115 is also known as the Audiomax SRW-710S and Kaimeda SRW-710S (and likely rebadged as a number of other models).

Click here to read reviews of this radio.

Retailers:

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The AirSpy HF+ R3 bypass modification

After SWling Post contributor, Guy Atkins, posted the survey results of his excellent Elad FDM-S2  vs AirSpy HF+ weak signal comparison, I received a few questions about the AirSpy HF+  “R3 Bypass” modification Guy mentioned in his post.

Guy has not yet performed the modification on his HF+–neither have I–but he points out that others have noted it: “significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues.”

I reached out to AirSpy president, Youssef Touil, for a little more insight about this modification. Youssef replied:

During the early phases of the design R3 was a place holder for a 0 ohms resistor that allows experimenters to customize the input impedance. For example:

  • A 300 pF capacitor will naturally filter the LW/MW bands for better performance in the HAM bands
  • A 10µH inductor would allow the use of electrically short antennas (E-Field probes) for MW and LW
  • A short (or high value capacitor) would get you the nominal 50 ohms impedance over the entire band, but then it’s the responsibility of the user to make sure his antenna has the right gain at the right band
  • A custom filter can also be inserted between the SMA and the tuner block if so desired.

Click to enlarge. (Photo source: RTL-S1DR.com)

R3 and the nearby resistors have been intentionally left outside of the RF shield, and their size was picked to be big enough to allow anyone to play with them. You will notice the size difference with the rest of the components.

In general, unless one knows what he’s doing, it’s not recommended to alter a working system. “If it’s working, don’t fix it”. But, we are hobbyists, and not doing so leaves an uncomfortable feeling of something unachieved. Most brands addressing the hobby market leave some tweaks and even label them in the PCB.

The main purpose of the HF+ is the best possible performance on HF at an affordable price. This is to incite HAMs to get started with this wonderful technology while using an SDR that isn’t worse than their existing analog rig.

The MW/LW/VLF crowd may have slightly different requirements, but that can be addressed by shorting a resistor.

Regards,

Youssef Touil

Thank you, Youssef, for replying to my inquiry so quickly and thoroughly.

No doubt, I too will eventually modify R3–it’s very difficult not to experiment, especially when a product was designed with the experimenter in mind.

I really feel like AirSpy has knocked it out of the ballpark with the HF+. For those of us primarily concerned with HF performance, this SDR is very hard to beat–especially at its $199 price point!

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Rolf’s Sony ICF-SW35 mod removes the beep sound

Many thanks to SWLing Post contributor, Rolf Snijder, who shares the following modification for the Sony ICF-SW35. The mod is very simple: remove one capacitor.

Rolf shows the capacitor location on the following images:

Click to enlarge.

Click to enlarge.

Thanks, once again, for sharing your modifications, Rolf!

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