If I seem a little bit distracted over the next couple of months, there’s a simple reason for it: I’ll be spending some extra time on eBay looking for the next tube type radio to repair for this coming winter DX season.
DX is ham radioese for distant or distance. And in the winter, especially after the holidays when there’s little besides “formula” television offered in media, nothing beat a tube-type radio, a hot cup of cocoa, and a large low-band antenna set-up.
On the 75-meter band (say from 3.75 MHZ up to 4 MHZ) you can strike up a conversation almost any night after dark, but in the summer there’s a lot of atmospheric noise that screws things up a bit.
Ingenious hams have come up with noise blankers and such, but the underlying noise is a problem often until close to 11 PM.
In the wintertime, however, the band can be open for DX as early as 5 to 6 PM.
Restoring old ham gear is something I don’t talk about much…but there is a way to actually make money restoring gear, if you know what you’re doing.
Unlike “appliance operators” those of us who know which end of the soldering iron goes where enjoy buying broken equipment and returning it to useful condition.
To do that, you need parts. And if you enjoy restoring tube-type gear, you’ll need to buy a tube-tester (like the kind that used to be in drug stores, back when televisions and radios still had tubes) and you’ll need a couple of good sources because there aren’t many tubes being made these days.
This fascination with tube technology isn’t limited to the odd nutter-in-the-woods, like (ahem) Ures truly.
There is a who underworld of hi-fi, musicians, and audiophiles who keep the tube selling business flourishing.
My two favorite sources are Bob’s EX Shop/The Tube Meister and the K5SVC store – both of them on eBay.
Tube-type radio gear is different from what I call “squalid-state” radios. ANYONE can write a $15,000 check and get a top of the line Icom, Yaesu, or Kenwood radio and a 60-foot (or higher) tower with a big rotatable beam antenna.
But that’s where the term “appliance operator” comes from. Morse Code is no longer required so between the Asian radio makers and the absence of Morse for us fundamentalists, tube-type gear is a kind of Last Bastion of Olde School.
With my son (KF7OCD) coming down for a visit, I’ve spent a few minutes on the bench this week restoring an old Swan 350-D. Got the receiver back to life – and since the receiver and transmitter share much of the same signal path, the transmitter part should be easy. I’ve already put in new driver and final amplifier tubes..
The most common problem in old radios is they develop terrible hum problems. This is invariably from dried out capacitors in power supplies. A search for old radio capacitors in Google will generate tons of leads. (Most of them, you can solder, lol.)
Since I imagine myself to be a “Hallicrafters Man” one of the best capacitor kit shops around is N0JMY’s Hayseed Hamfest site. Here, you can buy a complete capacitor kit for many of the classic Hallicrafters radios.
My favorite wintertime radio is the SX-117 receiver and matching HT-44 transmitter. They wouldn’t be complete without the legendary T.O. Keyer that automatically makes dots and dashes so you can blast through the 25 Word Per Minute Morse barrier.
Typically, my son will wander into my office/ham shack and ask an impertinent question like “Dad, why do you need all these radios? You already have the Kenwood 590S and it’s hard to be that…why all this junk?”
He’d have a good point – how many radios can one person operate simultaneously, after all.
Fortunately, it’s not that simple.
Part of the reason may be found on Robin Sherwood’s (Sherwood Engineering) website where he’s defined the art of measuring super-high performance radios.
Scroll down to Collins 75-S3B. Sporting a noise floor of –146 dbm this radio smokes modern equipment.
The reason is fairly straight-forward: Direct Digital Synthesis (DDS) and most other solid-state oscillators are not particularly “clean” when it comes to an ultra-pure sine wave to pump into a mixer stage. There can be phase noise/jitter/and anything less than a perfect sine wave evolves these byproducts.
That’s what even now, some of the best radios ever made were old school. I didn’t see a listing for the SX-117, but properly updated, it should be down in that –135 or better range.
It’s a lot like an artist with a paint brush.
Sure, the Kenwood will do everything, very well, including digital modes. The tube gear isn’t as good for that because old radio designs may drift a tiny bit – and that’s admittedly one downfall.
But tube type gear just sounds “warmer”. Over-drive a stage in a solid-state radio and as soon as you get there, distortion is in your face. In a tube radio, there’s a nice predictable flattening as a tube approaches nonlinearity and it’s this predictable aspect that made classic guitar amplifiers so warm-sounding.
Beyond picking the right radio for the mission, though, there is the matter of heat.
We don’t play with tube-type gear in Texas, much, between about the end of March through November first. No need for heat in that period.
But when the weather is down in the teens, the stars are so cold they don’t even twinkle…well, that’s when tube-type radios are amazing.
To really get an old radio whipped into shape is usually a 90-day process. The radio needs to be shipped. Then an initial assessment made. A work plan developed.
There are parts to be ordered after the first visit to the bench, including some tubes. The library of back issues of Electric Radio must be consulted for performance tweaks.
If you are totally into it, while the tubes and other parts are on order, there’s time to sand blast the cabinet, take the Dremel buffer to the chassis, or maybe even run the radio through the dishwasher.
Send your spouse shopping first.
If you can’t afford to sent your wife shopping, there are alternatives as laid out in this Instructable over here. The main thing is to be sure to destroy the evidence of any repurposing done in the kitchen.
Seems like an odd thing to be discussing, I’m sure. But tube radios, other than being relatively EMP proof, are great fun to work on provided you remember the “One hand in the pocket” rule and you’re careful to avoid shock with the hand doing the work.
Didn’t mean to get off onto a radio discussion this morning, but with this being a three day weekend coming up, there are just too many cool things to do – and time off for many – so why not talk about hobbies and what turns our crank?
One of the most dangerous aspects of reading UrbanSurvival is that you may develop a sense of “quality outside of time.”
It’s the reason I like 1980’s fiberglass sailboats, 1960s and 70s aircraft, and mid 80’s Porsches.
Done all of those..but beyond fixing yet another radio, I’m thinking about a new hobby/pursuit for next year when we plan to sell the airplane.
I’m thinking about an RV since it’s one of the few hobbies I haven’t done. And it could be interesting. Rehabbing an older RV “classic” might be fun…but still thinking on that one.
In the meantime, though, off to spend a few minutes a day over summer. That’s when a lot of great tube-type gear shows up.,
It’s like I learned from my motorcycling days.
Buy a motorcycle on the coldest, wettest, most miserable day of the year. A storm in early January is perfects. Find someone who needs money and drive a hard bargain.
Ride the bike for 6-months and sell it in July.
I’m starting to watch RV prices to see if I can spot the “natural cycle” in that one, but the ham radio hunting season is more or less open as of this weekend.
Oh, and if you find a complete Collins S-Line (with either the 30-L1 or the 30-S1 amplifier), please feel free to donate it to the cause.
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