"Ether" being, of course, the anachronistic notion of what the medium was that propagated electromagnetic waves. Analog radio being something of an anachronism itself, it feels appropriate.
Almost went down a rabbit hole on FM antenna polarization, but figured I'd better do this post or it'd never get done, since I overslept (or slept in) this morning.
Both the Superadios (GE trademark name) performed similarly on AM, and slightly outperformed the Panasonic RF-2200 in terms of being able to reproduce weak signals with reasonable clarity and volume. I will say that noise seemed better controlled on the RF-2200 though. I'm not sure why that may be, I'm little more than a dilettante in all this.
I used a Sangean PR-D5 as a digital (DSP) reference radio to identify the specific frequencies I was receiving on each radio. The PR-D5 is noted for being especially sensitive on AM, probably because of its larger than normal ferrite antenna, being similar in size to both the GEs and the Panasonic. DSP radios, when properly implemented, are more sensitive and selective than analog radios, certainly at least in the consumer space. It can also decode RDS (radio data system), so I can see the call letters if I don't hear them, if the station offers an RDS signal.
Later, I'll have to test more pedestrian radios on AM to see what the relative difference between a "super" radio and an ordinary one is, at least at my location. I had four radios on the table in front of me, and that was tough enough to manage, what with turning them to get the best signal and all.
FM was kind of a similar story; but a bit muddled, perhaps because of propagation conditions.
I received more stations than I expected, with Orlando being the known location of at least one of them, based on station ID in RDS. I didn't listen long enough for call letters in each case, and the others didn't decode in RDS. One was in Georgia, one in Gainesville, FL. This was unexpected, but VHF signals can often propagate beyond line of sight because of evaporative ducting. I saw this a great deal in the Arabian Gulf, where you could hear Channel 16, Bridge to Bridge, seemingly everywhere in the Gulf.
With AM, it's routine to turn the radio to get the strongest signal, with the long axis of the ferrite bar perpendicular to the direction of the antenna. Likewise, if there's a strong source of interference nearby, you can turn the radio to point the long axis toward the source of the interference, placing it in the antenna's null, reducing the amount of noise entering the receiver.
I confess I'm somewhat surprised to learn that changing the whip antenna's position also affects reception. Some signals are strongest with the antenna pointed vertically, other times horizontally. In some cases, there were two signals seemingly on top of each other, and you could get one clearly by orienting the antenna one way, and the other clearly by orienting it another way, to include changing its azimuth and elevation.
I thought there might be a simple explanation, but a quick look at the search results suggests otherwise, so I'm going to have to do some reading. At least it'll be interesting.
Of the two GEs, it's I think it's possible the SR II is more sensitive and selective on FM than the SR I, but I'm not sure. The PR-D5 would find a station, and I'd have to play around with turning off AFC (automatic frequency control) on the GEs to try and tune it in. AFC seemed to have a tendency to grab the strongest signal, to the exclusion of the weaker one, this perhaps being the intent of the function.
The tuning experience, in terms of the feel of the dial, is much better on the SR I. The SR II feels a little sloppy with some backlash in turning the dial. It works just fine, it just doesn't inspire confidence. That may just be an instance of sample-to-sample variation.
I remain somewhat astonished at the market for religious programming on radio. I think "political commentary" (demagoguery) and religious programming account for more programming on the air than music.
So, am I happy I spent $380 re-capping and repairing these two radios? Yes. Because I'm an old man, and it pleases me to spend some of my money making old things perform well again. Should you spend over $200 for a 30 to 40 year old radio and fix it up to have a "good" radio? Probably not. Unless you like old things.
Today's DSP radios, again, when properly implemented, will outperform consumer-grade analog radios from back in the day. You can look up what the PR-D5 goes for, but it's not much more than what eBay sellers seem to want for GE Superadios.
I guess I should comment on how they sound. Of the four radios I listened to yesterday, the SR I would be the one I found most pleasing. The SR II could be made to sound better, but it always required fiddling with the volume, bass and treble controls. That tweeter in the SR II can make the SR II sound reedy, less full. At its best, it offers a spectral clarity that the SR I can't match, with clear highs and a crisp mid-range, but it requires fiddling. The SR I always produced a rich, full sound that was pleasing to listen to.
The sound out of the PR-D5 is a bit of a disappointment. It's fine for news and talk, but it seems to perform better with music at higher volumes than are comfortable for "personal" listening. But it seems to me to be an amazing receiver in terms of being able to detect and demodulate low signal-strength broadcasts.
I bought a refurbed white one that looks good on the kitchen window sill. I don't think Mitzi is going to let it remain there, so it'll probably just be a reference radio for me when I'm "playing radio."
The RF-2200 sounds fine. It's great for its purpose, but it's strictly a low-volume affair. I was often having to crank it all the way up to hear weak signals, though the audio was clear. I don't know if there's an issue in the amplifier section, but strong signals played loudly enough so I suspect not.
The GEs seem to have a stronger amplifier driving a much larger speaker with six D-cells compared to four for the RF-2200. And the amplifier seems to respond non-linearly to the volume pots on the GEs. A little goes a long way on that control. I seldom (never?) had that control turned "up" more than maybe a quarter to a third of the way, the volume getting uncomfortably loud above that. And then there was always the fiddling that the SR II required.
So I still need to do some playing around with FM. I want to have a clear understanding of the mis-alignment on the SR II before I describe it to Chuck for possible re-alignment. It seems larger at the low end of the band, and it's a closed loop. At the bottom of the dial, I was getting stations from the top!
And I want to have a clearer understanding of the relative differences between the two radios in terms of their tuning performance. The SR II seemed to be slightly more selective, but then there was that feel of backlash in the knob.
Anyway, something to do outside before the weather becomes unbearably hot.
Originally posted at Nice Marmot 07:43 Friday, 31 March 2023