Amateur radio

gsb-100

I had planned to wait until a few of the current projects were complete, but this Gonset GSB-100 popped up locally and I couldn’t resist. These were produced from 1959 to maybe 1962, so it is contemporary with the early KWM-2. It covers eighty through ten meters; SSB, AM, PM (functionally similar to FM), and CW. It is well designed except for using a TV sweep tube for a final, and for apparently using an inadequate power transformer (these had a high failure rate). This one is dusty, but is in great cosmetic shape and appears to be complete. If the transformer is OK I should be able to bring it back to life. It will be a perfect match with the vintage homebrew amplifier I am refurbishing (using four 811-A’a and mercury vapor rectifiers). Someday I will need to come up with a communications receiver with which to mate it. Gonset didn’t make anything satisfactory so it will probably be a Hallicrafters or Hammerlund from the late fifties or early sixties. Maybe a 75S-1? A 75A-4 would be a better match (though not quite contemporary), being about the same size and also having a rotary drum dial – but the collectors have inflated prices on those far beyond their intrinsic value.

heathtwins

 

The first “serious” station I owned was the Heathkit SB-301/401 combo. I enjoyed contesting in the early 70’s and these, along with a home brew amplifier using a pair of 4-400A’s, did a fine job for me. I also had an Eico 730 modulator connected to the SB-401 finals in a plate modulation scheme so I had real AM capabilities; not a common thing in the 70’s. Many rigs of that era included the AM mode, but it was usually a low level thing, not much more than unbalancing the balanced SSB gemerator. I also had the matching SB-500 two meter transverter, which I used to communicate through AMSAT-Oscar satellites 6 and 7. All in all, I got more use out of the Heathkit twins than any other equipment I ever owned. It is no wonder that I would like to have a set of those twins available again.

I violated one of my own rules in acquiring this particular pair. I don’t mind repairing or refurbishing communications gear but don’t like to get involved in finicky cosmetic re-work so I usually look for gear with no external flaws. The receiver above has had its cabinet painted black at some point. This might have been done to match the blackout SB-200 that was offered one year. Still, the front panel and lettering are excellent and there are no dents. It won’t be very challenging to shoot the cabinet with a close enough color match. If not, I should stumble upon a replacement cabinet sooner or later.

I may actually get an antenna or two up tomorrow. If so, I’ll be busy setting up the FTDX-1200 station and running power, grounds, and coax for a little while. Then I can start getting some of this vintage gear whipped into shape. I have an extra desk with a riser in the office, so I should be able to have the Yeasu, the KWM-2, the S-38C, and the Heathkit twins all set up together at some future date (after everything is working, of course). I suspect there won’t be room there for any more projects. That is OK; this will be enough to keep me busy for a while. I suppose I could set up an alternate station in the upstairs office, as there is an extra desk there as well. I had originally planned to set up the station on that desk; the Yaesu and Kenwood transceivers are on there now – but I think I would enjoy it more downstairs. I can have a much better RF ground there, too.

sb-500

 

Most hams have probably never seen one of these SB-500 two meter transverters. No, I don’t have one (actually, I do have one but it will need to be refurbished), but I did have one back in the day. In the early 70’s the 2 meter ham band was still mostly AM (Johnson and Gonset radios come to mind – and of course the Heatkit lunchbox) but FM was on the rise (usually with converted low band land mobile radios). A few weak-signal fans were using CW. Pretty much nobody was using SSB, though, and when Heathkit introduced the SB-500 it did not create a firestorm of interest. It took in a signal from a ten meter (28MHz) transmitter and heterodyned it up to 2 meters (144 MHz), retaining whatever modulation was present.  Then it transmitted the new signal. Anyone with a ten meter SSB transmitter could rig  one of these to generate a two meter SSB signal. It was a turnkey setup if you had the SB-401 transmitter with which it was designed to mate. Like most, I wasn’t excited about it but approved of the idea in general.

That changed for me when Amsat-Oscar 6 was launched in 1972. This satellite, built by amateur radio enthusiasts, was in a low earth orbit similar to the weather satellites. One of the things it could do was to take in a span of spectrum (100KHz, I think) in the two meter band and translate the whole chunk down to ten meters and retransmit that span, including whatever signals were there. Thus, a whole group of people could be simultaneously using the system and each could be involved in his/her own conversation. That looked like fun! The satellite’s power budget was extremely limited, though. Only efficient modes of operation were permitted. This meant CW or SSB; I was equipped for neither on two meters.

I was using the Heathkit SB-301/401 on HF, though, so the SB-500 was a perfect solution. I managed to pick an SB-500 locally and after some work had it operational. I rigged omnidirectional antennas for the uplink and downlink frequencies and began listening. The satellite had an orbital period of around 110 minutes and an overhead pass lasted maybe 20 minutes. The inclination was such that I could usually hear two consecutive passes (three if the middle one was directly overhead).  I used both CW and SSB and had many enjoyable contacts through Oscar 6.

While Oscar 6 was still operational, Oscar 7 was launched. It had new capabilities but still had the 2 meter/10 meter translator so my setup worked well with both satellites. I had a lot of fun with both. I shut down my “ground station” when I relocated and never got set up for satellite work again but kept up with happenings. Eventually the batteries on Oscar 6 failed so we were down to one satellite. Around 1980 Oscar 7 also went silent due to a battery failure. Nearly 20 years later, someone noticed that it was back up! A shorted battery had put it out of commission but when the battery eventually rotted away it left an open circuit and the solar panels could again power the system. There is no storage, of course, so when the satellite is in Earth’s shadow it shuts down but most of the time it is up and fully operational despite being over 40 years old!

Clearly, I need to rig something to listen for the 10 meter downlink. I suspect that when I have done so, I will get the bug to relive my experiences all those decades ago and actually use it. The good news is that it will be much easier to set up a 2 meter SSB/CW rig these days.

S-38c

 

This arrived recently. Background: the first shortwave receiver I ever owned was a 1952 Hallicrafters S-38C. It was about ten years old at the time (as was I). Dunno what happened to it. Every five or ten years I wonder whether I should try to obtain one for old time’s sake. This time I did. Looks great, but (of course, for $20) doesn’t work. Into the project pile it goes – maybe with a little extra priority. Come to think of it, I think I paid $15 for the first one, and it worked…

The next receiver was a Heathkit GR-64 in 1968 or so. Bad mistake; I haven’t felt any nostalgia for that one. I built it to be the receiver in my first Novice station. It wasn’t a very good performer in that application (though it was better than the S-38). I was seduced by the features and glossy appearance but I soon realized that I should have selected the HR-10 instead for ham use. I don’t think I’ll be looking for a GR-64 to cherish.

When I got my General class I picked up an Eico 753 SSB/CW transceiver. It was better, but not well respected in the ham community. Then a few other transceivers until I got my next separate receiver. This one was designed for amateur use and was loosely modeled after the very highly respected Collins 75-S series receivers. It was a Heathkit SB-301 and worked alongside its companion SB-401 transmitter for several years until both were replaced by the Collins S-line (75S-1, 32S-1) it emulated. I don’t remember what happened to the S line, but that was the last tube receiver or transmitter that I owned. I could easily see me grabbing a set of Heathkit twins or an S-line again just to enjoy having them around.