You guys know how it is: You get tired of struggling with an old piece of gear. You put it aside, thinking that you might never work on it again. But it sits there in the corner, sort of looking at you. A few days or weeks or years pass and you think, hey, I'll take one more quick look at this thing to see if I can get it going.
That's what happened to me this weekend with the Hallicrafters S38-E. I hooked up the isolation transformer and put a fuse in the primary. I checked the wiring of my rewound antenna coil primary and found that I had connected it wrong. Duh. I then found that the antenna tuned circuit tracks fairly well with the tuned circuits in the local oscillator.
I hooked it up to my 40 meter dipole and fired it up. As evening rolled around the shortwave bands started to perk up. The Chinese Broadcast stations were there, as was that fire and brimstone preacher Brother so-and-so. But then I tuned into Radio Havana Cuba and the guy was talking about homebrew shortwave antennas. Could it be? Yes indeed. It was Arnie Coro CO2KK. The Radio Gods had spoken! They clearly had wanted me to get this old rig going.
I still have a few things to do: I need to fix the front panel light. I want to put in a three-wire (with ground) AC cord. Perhaps a real BFO (the original circuit seems to run out of steam with strong SSB signals). And I need to spruce up the alignment on the 1.7-5 Mc and 13-30 Mc bands.
I think Pete and I may have been too harsh on this old receiver (calling it a pig with lipstick and all that). It is clearly not a great communications receiver, but it is nice for casual shortwave listening.
And here is a bonus treat for you guys: Remember Radio Moscow in the bad old days? Yesterday I found a site with good recordings of some of their 1965 broadcasts. This is just what you would have heard coming out of an S38-E in 1965:
What about HCJB ? La Voz del los Andes! I remember in the 5th grade getting a QSL card from them along with a hand-carved wooden trinket and taking them to class as part of our World Geography studies. My dad purchased the S-38 (which I still have) new for me after some major surgery the previous summer. I went through the radio a few years ago and brought it all up to snuff. Now, I do have to come up with a replacement IF transformer (or rebuild)- it has the dreaded Silver Migration Disease. I guess I've got lipstick on my collar. My pig is right up front, sitting on the shelf in my radio room.
ReplyDeleteBruce - KK0S
There was an story in "73" about 1966, where some was taking his S38 to the ham store as a trade-in. He documents the mods he had to remove, and even on the drive to the store, he remembers one or two more tat he has to remove.
ReplyDeleteThere was a set of mods in CQ about the same time. The one that stands out was just adding a triode to the existing first tuned circuit, adding improvement by keeping the antenna from loading the tuned circuit down.
I never had n S38, but I did have a Hallicrafters S-120A, the solîd state one. One of their last receivers, I doubt it was their design. All the bad of low end receivers, plus the overload of transistors. It had a BFO, but couldn't receive SSB, unless I attenuated the incoming signal a whole lot, with a pot, though at least I was understanding enough to get to that point. I later saw one review of tat sort of receiver, they discussed image rejection on the highest band, "we could barely tell the desired signal from the image".
About five years ago, I got a Grundig Mini 300 pocket SW radio at a garage sale for $2.00 (half an hour after buying a Sony SW-1 for ten dollars). The Grundig is awful, but even at new price was less than I paid for the S-120A in 1971. I suspect the circuitry of each was about the same. The one way the pocket radio was an improvement was it used a frequency counter for the dial. It made the overall circuit so much more complicated, but added little in cost or component count. The addition meant much better dial accuracy (the S-120A had a thick pointer apart from everything else), but no big dial and the mechanicals behind it. No calibration either. And then the tuning range is broken into small bands, so no need for reduction gear, the thumbwheel tuning wasn't too much trouble. That's design, make something more complicated to ease something else.
Michael
Thanks Bill,
ReplyDeleteFor removing the pig and lipstick image. And for adding this video.
73, Dave, K1KA