Here are two more great museum visits by Helge LA6NCA. In these two he visits Ragnar LA1UH.
Ragnar has a lot of maritime experience, so we see a lot of older ships' radios. But his interest in the radio art is much broader and we also see a lot of other kinds of gear:
-- Wow, a "travel radio" in a suitcase from 1927. Was this the idea that later lead to the Parasets of WWII?
-- Lots of "Stay Behind" gear from the Cold War. That "Africa" receiver (that never made it to Africa!) is very interesting.
-- We see an ART-13 with autotune, ANGRC-9s, several ARC-5 command sets. I was hoping Raganar would fire up a Dynamotor, but no.
-- I spotted a Galaxy V transceiver. I have the VFO reduction drive from one of these in my homebrew 15/10 rig.
-- We see several variometers in the emergency (500kc?) maritime transmitter. I used a variometer in my super-simple ET-2 transceiver (with an N0WVA receiver).
-- Lots and lots of tubes.
Ragnar says he himself is of 1944 vintage. I hope some "stay behind" provisions have been made for these amazing museums.
I hope readers have picked up on the discussion of the Islander DSB rig out of Cuba. We had a bit of a breakthrough on this recently. I've been writing about it on the blog:
One thing I think is especially interesting: The Cubans were using parts taken out of old Soviet TV sets. One of the tubes used in the VFO section of the Islander was known among the Cuban hams as "the little spider."
Arnie Coro CO2KK explains why:
"VFO is made with ONE of the 6 "little spider" 5 pentodes... By the way, I am sure you will like to know why the tube is locally known like that... the ZHE letter of the Cyrillic alphabet is something difficult to pronounce to a Cuban - or any other non slavic for the matter - and it resembles like a little spider on the tube's carton and... that's why it is not a 6 "ZHE" 5 but a 6 "little spider" five!!!"
Islander boards recently obtained in Cuba by CO7WT
Pavel CO7WT is making great progress in re-building an Islander DSB rig, the same kind of rig that got him started in ham radio, and that was so popular in Cuba years ago. Here are some background blog posts on this rig: https://soldersmoke.blogspot.com/search?q=Islander In essence, the Islander was the earlier tube DSB/CW rig; the Jaguey was a later, solid-state DSB/CW rig.
When they get this Islander going, hams outside Cuba should definitely try to work this re-creation of an important rig.
Thanks Pavel for all the information. I will share with the group info that Pavel sent about temperature stabilization techniques used on this rig.
Pavel CO7WT writes:
Great news, today I received the package from my colleague in zone 6.
Two original islander motherboards and one from the vfo!
I'm doing a search among old technical friends in the city and in the country to see if I can put together at least a transceiver motherboard.
Audio triode-pentode is easy, as is tx pentode and audio double triode.
The difficult ones would be the 6cb6 and 6bz6 of the receiver... At least according to what I have polled among my local friends...
Tomorrow some friends are going to start looking for bases and valves that can be used to build a trx islander.
All out of pure nostalgia. I intend to make it qrp, that is, up to the output pentode, which there is between 3-5W of power, that is enough for me.
I am looking for alternatives for small sources, perhaps I will use switching for the filaments and we will see what I can get for the 180-250v of the plates.
Earlier:
CO7WT here, built a pair of the Islander back in the time, the most scary part was the power supply.
The 600V is 300ish V from the transformed DOUBLED stright from the transformer and if you look closely on the diagram the doubling capacitor need to be of good quality otherwise it will explode in the spot.
As you can imagine, using scrapped parts means that very often this capacitor explodes, even after a few months of duty, that was a common problem.
We used to use 47uF/800v from Germany that was almost easy to obtain, but exploded like fireworks a given day.
Later I learned that if you put a resistor of about 1k 5W in series and work it for a while like this [no real voltage at the end] it will behave in the future and this trick saved many, a trick that was shared with Coro CO2KK and he found the explanation on the taming/training of the dielectric after storage/inactivity will prevent it from exploding.
I think he made mention this on a DXers Unlimited program...
Grayson Evans KJ7UM is the author of Hollow-State Design for the Radio Amateur, a wonderful book about using Thermatrons (aka tubes, or valves) in radio projects. Buy it here:
This is probably Jean Shepherd's best program about homebrew ham radio. It is about how we can become obsessed with the problems that arise with equipment that we have built ourselves, and how normal people cannot understand our obsessions.
I posted about this back in 2008, but I was listening to it again today, and quickly realized that it is worth re-posting. Realize that Shepherd's Heising modulation problems happened almost 90 years ago. But the same kind of obsession affect the homebrewers of today.
Note too how Shepherd talks about "Heising" in Heising modulation. Heising has an entire circuit named for him, just like Hartley, Colpitts, and Pierce of oscillator fame. Sometimes, when I tell another ham that my rig is homebrew, I get a kind of snide, snarky, loaded question: "Well, did you DESIGN it yourself?" This seems to be a way for appliance operators to deal with the fact that while they never build anything, someone else out there does melt solder. They seem to think that the fact that you did not design the rig yourself makes your accomplishment less impressive, less threatening. This week I responded to this question with Shepherd's observation -- I told the enquiring ham that my rig is in fact homebrewed, but that I had not invented the Colpitts oscillator, nor the common emitter amplifier, not the diode ring mixer, nor the low-pass filter. But yes, the rig is homebrew, as was Shepherd's Heising modulator.
Guys, stop what you are doing. Put down that soldering iron, or that cold Miller High Life ("the champagne of bottled beer") and click on the link below. You will be transported back to 1965 (and 1934!), and will hear master story-teller Jean Shepherd (K2ORS) describing his teenage case of The Knack. He discusses his efforts to build a Heising modulated transmitter for 160 meters. He had trouble getting it working, and became obsessed with the problem, obsessed to the point that a girl he was dating concluded that there was "something wrong with him" and that his mother "should take him to a doctor."
This one is REALLY good. It takes him a few minutes to get to the radio stuff, but it is worth the wait. More to follow. EXCELSIOR! FLICK LIVES!
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