Many thanks to SWLing Post contributor, Paolo Viappiani (SWL I1-11437), who shares the following guest post. Note that, as with any radio modification, perform this operation at your own risk. This is a very simple mod, but if you feel it might be beyond your skill level, consider hiring a radio technician to perform it on your behalf:
Unblocking the YAESU FRG-8800 Frequency Coverage Limitations
by Paolo Viappiani
Figure I: An unblocked FRG-8800 receiver tuned to 29.999.9 MHz.
It is well known that some receivers produced in the last decades of the last century suffered from a limited frequency coverage due to legislative restrictions in force in some countries (Germany, Australia, etc.).
In particular, in Germany it was forbidden to listen to HF frequencies higher than 26.1 MHz, while in other Countries shortwave were not allowed to receive frequencies below 2 MHz.
These restrictions led most radio manufacturers to produce “blocked” versions of their HF receivers in order to satisfy the various national requirements; almost classical examples are the world renowned SONY ICF-2001D and the PHILIPS D-2935/D-2999 portables.
The blocking/unblocking procedure of some frequency bands was quite simple in microprocessor-governed synthesized radios: usually it was sufficient to add (or remove) proper jumpers in the vicinity of the microprocessor to perform the task, and the correct procedure was often covered in the Service Manuals or in specific Technical Bulletins; in any case plenty of information can be found on the Internet. Continue reading →
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’sRadio 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:
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.[…]
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.[…]
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.[…]
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.[…]
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.
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:
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:
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!