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.
Read more about fixing the old 645 Keyer …
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 …
Read more about the Corsair II …
Figure 1: An almost forty year old Alda 103A amateur band transceiver. Click to enlarge.
The Alda 103 has a very interesting history. It was manufactured (IIRC) in 1977 and 1978, which means it has a nice complement of the discrete bipolar transistors that are fairly common (now, almost 40 years later) – and thus replaceable. Readers of some of my other articles may have observed that I like to have the ability to fix …
Read More about the Alda …
For the curious, my Alda 103A rig is on youtube:
Youtube Alda transceiver tour
Figure 1: Quisk running on the second “homemade” tablet, which use a Pi2 SoC SBC board. (Click to enlarge).
Some of the other posts on this site refer to my “homemade” tablet, which I subsequently outfitted with components for ham radio usage. I recently built another “homemade” tablet, this time using a Raspberry Pi2 board for the computing power.
Read More …
Note: This author is not affiliated with the Raspberry Pi/Pi2. For information about those projects visit http://www.raspberrypi.org. “Raspberry Pi is a trademark of the Raspberry Pi Foundation. Figure 1 contains elements of a desktop system and associated programs that have been released under a free software license (Copyright: LXDE team: http://lxde.org). As a derivative work, the respective part of the screenshot in Figure 2 falls under that same license. The full text of the licences may be found at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html. Fig1 contains another program that has been released under a free software license (Quisk). As a derivative work of that program, the respective part of the screenshot in Figure 1 falls under the same license (GNU GPL). This site/author has no affiliation with the author of the Quisk program. The code and full text license for Quisk may be found at https://pypi.python.org/pypi/quisk/.