Over the years I’ve had a number of radios, both digital and analog. In that time I’ve had a number of damaged radios that were impacted due to (I assume) electrical storms in the vicinity of the QTH of the damaged gear. I have always used lightening arresters and so forth, and proper grounding, but there is a certain amount of energy that gets into the shack from nearby storms that are not producing any direct hits, but still do manage to produce a lot of ambient energy.
I’ve noticed that the old analog radios seem to stand up to the storm, so to speak, better than the digital ones (now this is anecdotal information that only involves four radios, so it could be insufficient for the making of any conclusions).
In the first case I had two radios hooked up to the antenna and rig switching network, with one being an analog (oldie from the seventies) radio, and one being a newer digital radio. The digital radio suffered a failure, while the analog radio (the oldie) did not. The second case was similar, with another older analog radio hooked up at the same time as a second digital radio. The result was also similar, as the analog radio sailed right through and the digital one suffered a failure.
If you think about it, the old analog transistors would seem to be hardier things than a fet or a logic chip. The MOS technology builds a capacitor into every device, which may not handle a lot of voltage. Often, they do not. Sure, some of the big MOSFET power transistors can take higher voltages, but many of the others are very low voltage devices. Any old NPN analog transistor will likely have a collector-base breakdown of over a hundred volts, and often have a collector-emitter breakdown limit of near that amount. So, they just seem to be the hardier devices.
I suppose that one could go back to the old tube type radios for even more hardening, but that’s too rustic for me. I’ll stick with the old analog dogs, that are old but not antique! I guess I just have a hankering for the old things, and this is just another rationalization for me to collect more of them.
Figure 1:The ball bearing assembly, extracted from the old keyer
The old TenTec Ultramatic Keyer is still used today by many amateurs, including myself. Its Ultramatic keyer mode was born in 1953, and later overtaken by the Iambic A and B modes. I still use the two of these keyers that I own, but one recently needed a repair … In the video shown in figure 2, you can watch a 35 second walk-thru of the disassembly and repair.
Figure 3: A closer look at the Corsair II (left of photo). Click to enlarge.
The first thing I did with the new-to-me Corsair II was to check the output voltage coming from the TenTec power supply that accompanied the radio. These old power supplies can suffer from shifted component values over the decades. It turned out that the TenTec power supply was putting out around 14.5 volts – a shade on the high side. I took the cover off, and ran the adjustment trimmer down to a more appropriate 13.8 volts. The previous owner had mentioned a little problem with the display not always working. I noticed this too – but the problem seemed to go away when the voltage was reduced.
It took a little while to get used to the Corsair II’s pass-band tuning and its other various selectivity features. Once I got the hang of them, I found that …
Figure 1:The venerable? Heathkit GR-78 receiver, as it was found in flea market.
What ham can resist the allure of a piece of vintage gear, sans cover, knob, and a part or three, looking ever like the cartoon character with sprigs of pointy hair wires protruding from it, and connected to nothing? When we go to ham swap ‘n shops, we brace ourselves ahead of time, lest we not load our trunks with the contents of theirs. We have time in such cases to revisit the vision of our junk corners at home, and the XYL’s displeasure of same.
Another Alda? I’ll admit to having an affinity for them. The one I already have is the 80-40-15 tribander (the 103A) – and the one I’m unboxing is the 80-40-20 tribander (the 103). The package came in a solid little Home Depot box, and no shaking or rattling could be heard during a shake-test next to my ear. The question on my mind? Would I hear more from the speaker of the actual 103 when I finished opening the package and plugging the little gem-from-the-past into my supply?
Figure 1:A preamp tossed together on a piece of proto-board. Click to enlarge.
The performance of the Soft66 Lite is alright for the price of a couple fast food dinners, so I’ve no complaints. But, I thought maybe some shoes could help it get a better footing, and bring those sought-after WX faxes down to earth with more clarity. I thought “Why not give it a shot?”
Figure 1:The DIP socket in the little SDR board is populated for a BPF.
New Orleans Coast Guard weather fax operates at 4.317 MHz, so it is far outside of the default (7 MHz) filter bandwidth of the little sidecar SDR. Currently, I have no bandpass switching arrangement in the sidecar, so I have to pull and insert different 16 pin dip sockets loaded with the correct components for the BPF for the frequency I’m using. Yes – that is a little inconvenient …
Figure 1:Various combinations that have, thus far been considered for ham radio audio duty (see text for explanation).
For the past couple years, I have been attempting to determine what might be the best platform for ham radio and other communications related applications, with a bias projected towards looking at mobile platforms. The graphic (above) shows a few options that I have seriously considered, and a couple for which I have built prototypes to aid in the testing process. The graphic is not intended to imply any capability or lack of capability with respect to the hardware, the SoC chip based SBC boards, or the operating systems. The selection only implies what I have made as a personal preference, for reasons that (shortly) – I’ll enumerate. In other words, the Raspberry Pi may use USB Audio, but I would prefer I2S if I can make it work. Many alternate combinations are possible, and I have refined a list of preferences for the audio configurations I’ll use. I have more info about this subject at: