Converting old shortwave radio with external ground to internal(?) ground

I'm still working on trying out the wire-to-outlet-screw system & MarcelvdG's dipole idea - been busy with old car repair issues. :smash:

Speaking of troubleshooting issues: this is AM, not shortwave but still thought this was interesting. I was watching a video of a youtuber testing a 50 year old Heathkit guitar fuzz pedal & suddenly an AM broadcast could be heard through it! This time-stamped link will bring you to that part.
 
I bought a little Kaito
Sangean, Tecsun, Xhdata are others. The $45 Xhdata D-109 was pulling in a listenable New Zealand on my Toronto couch last night with ~12 ft of wire tossed over the curtain rod. YouTube has no end of receiver reviews.
Another antenna option is a DIY shielded loop. Plenty of how-tos from a Google search using regular coax and baluns made from VGA cable ferrites. Most discuss Mobius types but I found a simple split loop as effective. Best performance is below 10 MHz in my experience. Playing with baluns got it equivalent to the radio whip above that frequency.
 
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Ferrite rod loop antennas can be very small, to the extent that they can be hidden in a way to circumvent prohibition of antennas. An email group dedicated to loop antennas is https://groups.io/g/loopantennas
With a low noise low input impedance preamp, the loop can be wideband. Comparison of performance is possible via simulation, loop only (using low impedance, 5R) is rather flat.
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It's been awhile! But I was finally able to hook up my Globe Patrol receiver properly & listen to it for a few weeks.

BTW: thanks to rdf and Aridace for the antenna advice. I've always been fascinated with antenna technology - I know there's science behind their design & operation but they still have a....mysterious.....quality to them.

Anyway....

Not exactly good news to report. With the ground wire connected to the outlet cover plate screw, radio is now much more stable but tuning quality is, well, terrible. I can hear quite a few stations - along with a lot of static - but they blend together & the bandspread and regeneration controls do little to separate them/increase their volume. So basically, nearly useless. This radio was never that great but it wasn't THIS bad. FYI: the last time I used it was back in 1992 and was able to pick up, among others, an Australian music station broadcasting a folk tune about a man's sheep station (I had to look that up: "station" is the Australian word for ranch).

Other problems: as I mentioned before, the several electrolytic capacitors it uses could be bad (age, leaking, etc) and in turn affecting the radio's performance, but found another possible problem: two of its three transistors are of the germanium type & those can also go bad due to age. :( Substituting germanium types with silicon-based transistors is supposedly possible but not without major circuit "tweaking", something I am not qualified to do.

Oh well I tried. But this does give me an excuse to save up to buy a better new shortwave receiver, probably something in the $100 range. :cool:
 
With the ground wire connected to the outlet cover plate screw, radio is now much more stable but tuning quality is, well, terrible.
Probably the radio is getting overloaded with too much signal strength and or its frequency selectivity isn't that good to begin with. Low cost radios often have similar issues.

You might try connecting with a variable capacitor in series with the ground connection. Then you could try adjusting the capacitor to vary the coupling. The cap value would also depend on the frequency range. You might try an old AM radio tuning variable capacitor. If still to much coupling with it set to minimum capacitance, you could add another small cap in series with it to reduce the total capacitance.

You could also try some other things too but the above might be one of the more simple.
 
If you want to play with radio, get a cheap SDR (software defined radio) USB dongle from Sparkfun or Amazon. Shortwave radio is dead. 50 years ago before the internet, such a gadget was useful but not anymore. The air is full of interference and the only SW stations are religious or political propaganda. Ham radio operators are few and have moved to digital packet radio.

There are several other problems with your regen receiver. In those days, a "Shortwave" antenna and ground was wired as if it was a low frequency circuit because few had a good understanding of antennas, transmission line impedance and radio waves. It never did work very well but in those days there was something to listen to. Not anymore.
 
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It's true that the performance of SDR by far exceeds that of conventional radios. Variable bandwidth, noise limiting and reduction, audio filtering, AM (+ sync), FM, USB, LSB, digital modes like DRM. It's also true that in many countries, wireless broadcasting is coming to an end. The c19 years accelerated that very much, best example here was Radio Rebelde (Cuba), once a powerhouse at 5025 KHz and foreign service at 5040 KHz. The latter was shelved, 5025 (regional service) reduced power with ~20 dB, now weaker than the famous Radio Tarma (Peru) at 4775 KHz (nice music between midnight and 2 UTC). AM is very much alive in Latin America, low power stations with audio up to 10 KHz like Radio Morena (Ecuador) 640 KHz which I can receive after sunset.
In Asia a lot of DRM (MW, SW) in India, China and N. Korea SW but not intended for reception in "the West" so you need something better than "good enough" antenna. Hence my priority of designing and building such types of antennas.

None of these SDR sets is perfect, a good compromise is RSPdx as it also provides acceptable FM reception and provides "good enough" sensitivity. Last reviewed by Elektor at
https://www.elektormagazine.com/news/sdrplay-rspdx-review
 
Try using a dipole antenna with a coaxial cable, connect shield to ground.
Use a gang / variable cap if you see fit.

And look in Ham Radio forums, there may be receivers going cheap there, as people upgrade or scrap their sets, the specific term is 'communications receivers', those are much better made than commercial sets.
 
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It might be a good idea to listen to SDR online, to get an idea of what's available. One of the best is
http://websdr.ewi.utwente.nl:8901
which also uses the mini-whip antenna. My sims of it even helped improve it (1st stage became a dual gate mosfet instead of jfet) and daytime reception is very good. It can serve as example of what you could expect when providing a radio with properly situated antenna. Knowledge of law can also help: in many countries it's a fundamental right to listen to any national broadcasting station. That implies, the producer of EMI has to make changes to allow reception. In my case, I'm preparing a case against the power company for the 3rd time as the EMI invariably returns after ~ 1 year.
 
If you want to play with radio, get a cheap SDR (software defined radio) USB dongle from Sparkfun or Amazon. Shortwave radio is dead. 50 years ago before the internet, such a gadget was useful but not anymore. The air is full of interference and the only SW stations are religious or political propaganda. Ham radio operators are few and have moved to digital packet radio.
SDR sounds interesting. :unsure:

After playing around with my Kaito for a couple months with a suspended 10ft wire with its last @6" end wrapped around its whip antenna, I did notice there wasn't much for me to listen to - well nothing actually - as far as neutral news broadcasts or my type of music (e.g. rock, punk, folk). I've always enjoyed radio technology & admit I am living in the past a bit by trying to get the Globe Patrol working again. And, I may be watching too many movies with dystopian themes ;) but shortwave may still prove useful during certain times when more sophisticated means of communication go down.
 
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Some 30 years ago, "ground" still was simple. Nowadays, as apartment dweller with plumbing, gutter etc. "grounded" 10m or more below the apartment, what's considered as "ground" is ground with a long conductor added, and it picks up everything from the apartments it passes. So even if you would connect a perfect, noise-free antenna, the difference between antenna and "ground" still is a mess. But it's worse than that, as mains operated radios often have the chassis connected to "neutral" which, just like "ground, picks up much noise. In order to evaluate the situation, you would need a battery operated radio with an active dipole antenna, to discover major noise sources and locations where most noise can be nulled.
 
I worked afternoons after school and weekends at Radio Shack and built one of the Globe Patrols for myself, and fixed a few others that got brought in, and they were all poor performers. A lot of hams still like regenerative receivers and even say they are capable of startlingly good performance over relatively small frequency excursions, but I will never know. The Globe Patrol soured me on regenerative receivers forever - it was my one and done.

There is still quite a bit of shortwave broadcast activity that is easily receivable in North America. New Zealand is easily receivable in the morning here in the south central United States. Radio Romania has a north american show in the early evening. WRMI has classic rock every night until after midnight. There is more, but those are what I typically listen to with my available time.

At my second house I can receive all of those easily, pretty much like a local, with a homemade receiver and a 50 foot end fed untuned antenna. If you are living in an apartment building, you are likely going to need some way to try to null your local noise. A loop might work, or one of the boxes that fools around with the phase from a sense antenna. You could always ask to put up an inconspicuous wire antenna. My landlord in college had no problem with one. And you probably need to get a different receiver.​

Win W5JAG
 
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