Unusual tubes.
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the 3-500Z was a popular way illegal CB amplifier tube years back. Its an RF transmitter tube.
not cheap either
3-500ZG Transmitting Tubes (rfparts.com)
probably could be run as a modulator, which is just an audio amp that couples to a transmitter instead of a speaker.
https://tube-data.com/sheets/140/3/3-500Z.pdf
500 watts plate dissipation, in AB2 push-pull it can make some 1400 watts of output with a mere 3kw on the plate.
not cheap either
3-500ZG Transmitting Tubes (rfparts.com)
probably could be run as a modulator, which is just an audio amp that couples to a transmitter instead of a speaker.
https://tube-data.com/sheets/140/3/3-500Z.pdf
500 watts plate dissipation, in AB2 push-pull it can make some 1400 watts of output with a mere 3kw on the plate.
EL504
Active Member
If you scroll a bit down to "Usage in Models" and click on the years you will be led to some equipment they were used in: https://www.radiomuseum.org/tubes/tube_3-500z.html
Ham transmitters
All correct. I have a 3-500Z tube which unfortunately has suffered a catastrophic failure at some point, and is good for display purposes only. A shame, since they put out a fair bit of power when working, and unlike the audio tubes we're used to, are accustomed to running with glowing red plates:
Personally, I don't yet have an amplifier which uses this style of tube, though I wouldn't mind finding a Kenwood TL-922(A) at some point. What I do have is a Heathkit SB-200, which uses a pair of 572B tubes as finals, and is supposedly good for around a kilowatt:
Personally, I don't yet have an amplifier which uses this style of tube, though I wouldn't mind finding a Kenwood TL-922(A) at some point. What I do have is a Heathkit SB-200, which uses a pair of 572B tubes as finals, and is supposedly good for around a kilowatt:
I bought a SB-220 (pair of 3-500Z) new in the mid '70s and used it for many years. I still have a Gonset GSB-201 amplifier using four 811As that can output more than 1,500W. The choke-input power supply is rated for 1,500V at 1A. I've often thought about stripping out the supply and using it for audio, but the resulting amp would have to be permanently attached to a hand truck.All correct. I have a 3-500Z tube which unfortunately has suffered a catastrophic failure at some point, and is good for display purposes only. A shame, since they put out a fair bit of power when working, and unlike the audio tubes we're used to, are accustomed to running with glowing red plates:
Personally, I don't yet have an amplifier which uses this style of tube, though I wouldn't mind finding a Kenwood TL-922(A) at some point. What I do have is a Heathkit SB-200, which uses a pair of 572B tubes as finals, and is supposedly good for around a kilowatt:
View attachment 2669955
Jack
Pio1980
AK Member
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linuxslate
Well-Known Member
The 1969 Radio Amateur's Handbook featured a build of a 2KW PEP RF Amplifier using a pair of 3-500Z's. It was good for 15 or 10 Meters (Yes, it would work on "That other band", too). The power supply was separate, but pretty straight-forward.
Cooling was provided by a single muffin fan that just pressurized the underside of the chassis so that air was forced up through the tube sockets.
The various coils and chokes, and how they fed the plates gives it a cool "mad scientist" look.
Article starts on page 201.
Cooling was provided by a single muffin fan that just pressurized the underside of the chassis so that air was forced up through the tube sockets.
The various coils and chokes, and how they fed the plates gives it a cool "mad scientist" look.
Article starts on page 201.
Caboverbob
Member
I've been inside of a local 11 meter operators station, two 80k monsters and a professionally engineered 400a utility service. He talks anywhere he wats.......I bought a SB-220 (pair of 3-500Z) new in the mid '70s and used it for many years. I still have a Gonset GSB-201 amplifier using four 811As that can output more than 1,500W. The choke-input power supply is rated for 1,500V at 1A. I've often thought about stripping out the supply and using it for audio, but the resulting amp would have to be permanently attached to a hand truck.
Jack
Pio1980
AK Member
Like fishing with dynamite for a hobbyist, not much propagation challenge. What's the antenna array?
How's he hasn't had the visit from the feds? Remote country living so he doesn't get into folks cable TV and household appliances?
Caboverbob
Member
I
I get down on 11m with my 2 x 2SC2290 RCI 6300F150 @ around 220w in my truck and talk coast to coast daily.
567 Caboverbob on the west side.......
You guys familiar with 11m might of heard of him, Bullet Bob, lives in a very densely populated neighborhood and has the nicest house in the area. Couple of antennas to choose from, the big one is a custom design by Prime Minista (aka Sir Mix A Lot). Not my cup of tea but.......
I get down on 11m with my 2 x 2SC2290 RCI 6300F150 @ around 220w in my truck and talk coast to coast daily.
567 Caboverbob on the west side.......
Caboverbob
Member
And ya, my station is very small and I always try for the other small stations, all that power takes the challenge out of the equation.
I haven't actually turned any of my stuff on in a long time. Most of the guys I used to talk to have passed on. I should see if anyone is even on the band anymore. I have a range of stuff from the middle 60s through the early 80s and its all covered in dust. The tube gear I'd have to bring up on a variac, its been so long that I'd be afraid to try and shock it back to life.
Pio1980
AK Member
Fly fishing vs magneto fishing.
I used to participate in bcb DX contesting with passive crystal receivers, not dissimilar to the sophisticated Marconi era passive sets before regenerative tube detectors revolutionized reliable long distance reception.
Nothing like the Philmore or Cub Scout oatmeal coil sets, they are usually double-tuned two circuit loose coupled sets with impedance matched high sensitivity balanced armature headsets. Maximize sensitivity and Q while minimising insertion loss, Ben Tongue (R. I. P.) dedicated a website to the technicalities, which is available.
Guy in Hawaii used to almost always come in first, I could never jump the Rockies from here, KOA Denver was as far West as I could grab.
Fun times, still have a couple of the sets.
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