• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

Lee de Forest's wonderful invention

Joined
Dec 25, 2008
Messages
3,071
Location
New Zealand
#21
Vintage 1950's aircraft were mainly 28VDC - batteries and generators - right up to Convairs, DC3's and Fairchild 227's. Motor inverters supplied 115v 400Hz AC for mainly synchro driven instruments. VHF receivers had small inverters for B+ and the transmitters substantially larger devices which also incorporated blowers to keep the PA's cool - the whole transmitter was not that much different from the ARC-5's. ISTR that the output tube was a QQV03-40A or something like that.

Vintage-Collins-Aircraft-Radio-VHF-Transmitter-TSO-C37-Type.jpg
 
Last edited:
Joined
Apr 9, 2018
Messages
241
Location
CO, USA
#22
Cosmic rays do come fairly frequently but I don't think they occur frequently enough to get pictures of stealth airplanes moving much much faster than mummies in pyramids.

---

Incidentally after picking up a vacuum tube tester I was staring into the vacuum tubes that I have. They're all indirectly heated cathodes so most of the filaments are hidden behind an opaque cathode if not also a fully surrounding plate. However what I didn't notice all these years is not only the filaments get red hot, the indirectly heated cathodes get red hot too (in general)! (The 50C5 generally gets quite hot... and I don't think I have any that the plate (normally) gets red hot too...)
 
Last edited:
Joined
Jun 13, 2018
Messages
335
Location
Colorado, New Mexico- and now in Washington DC
#23
The 50C5 generally gets quite hot... and I don't think I have any that the plate (normally) gets red hot too...

.

Smiles- that's one thing you don't want to see -- a red (or orange- or yellow) Plate !.. Something is definitely wrong then ! :)

Old timers have told me of how they adjusted the Plate current resonance dip by watching the colour of those plates.

"..........Can't trust the meters"

______________________________________________________________________

We had (my father) an ancient WW2 real boat anchor- a BC 610E. When we moved from one station (Air Force family) to another my mother would always groan that we were overweight on our household goods (translate that as $'s)- but the 610 usually went with us.

To my point- that transmitter had a 250TH final- about the size and appearance of a very! big light bulb-- glass envelope and a filament that glowed white (as many high power'd tubes do.)

When it was run 'full out" (Hi-Pwr) my father would watch its plate's colour- a nice mild cherry glow on AM.
Seeing it glow like that always made me nervous (glowing plates still do :)) But he would shrugged it off.....
.
.

Lauri :sneaky:


(the Beast- note the glowing pair of 100TH's- the plate modulator's- the 610 had beautiful AM !)

(Also note all that open wiring- over 2.5KV in there-- it had safety interlocks, but one nibble from that plate cap and it was "goodnight ladies!":oops: )
 

Attachments

Last edited:
Joined
Apr 9, 2018
Messages
241
Location
CO, USA
#24
Weird, thought that it was "normal" for 50C5's to get slightly red when warmed up, at least that's what it seemed to look like when I had my radio on for a while. Last I checked with an IR thermometer, that tube by far gets hottest of them all. I'll have to take a picture of that tube after it's been on a while with the camera on highest sensitivity...
 
Joined
Jun 13, 2018
Messages
335
Location
Colorado, New Mexico- and now in Washington DC
#25
My fascination with old tube technology extends to this little gem.

Its an Eimac 15E - something I found in my New Mexico lab's 'junk room' -- where in we have stuff that probably dates to the Manhattan Project. :)

Its a cute little high frequency tube that I have no idea what it went in-
But you can plainly see its plate and grid ; strange it looks, for the grid comes off the top.

It graces my little 'museum'- and if anyone knows about a 15E I'd love to hear it.

Lauri :sneaky:
 

Attachments

Joined
Dec 22, 2013
Messages
2,824
#26
My fascination with old tube technology extends to this little gem.

Its an Eimac 15E - something I found in my New Mexico lab's 'junk room' -- where in we have stuff that probably dates to the Manhattan Project. :)

Its a cute little high frequency tube that I have no idea what it went in-
But you can plainly see its plate and grid ; strange it looks, for the grid comes off the top.

It graces my little 'museum'- and if anyone knows about a 15E I'd love to hear it.

Lauri :sneaky:
Designed for 515 mc Radar!

15E @ The Valve Museum

Sent from my SM-T350 using Tapatalk
 
Joined
Feb 6, 2007
Messages
5,880
Location
175 DME, HEC 358° Radial
#29
Are there any hams still using tube equipment?
Probably people with PLL radios with TCXOs frown at all those tube users for being 5Hz off center, forcing them to upgrade...?
Yes, lots. I mean, LOTS.

There are still people building tube equipment, although now it's intentionally done as an anachronistic exercise. Premium tube gear (Collins, for example) still commands high prices,and has performance to justify it. It can have audio characteristics that are very pleasing to the ear that can't be duplicated with modern equipment.
 
Joined
Apr 9, 2018
Messages
241
Location
CO, USA
#30
Oof, forgot to qualify: all tube units, transmit and receive, not just power amplifier RF or AF stages. Semiconductor diodes are okay but no transistors or ICs - was wondering about complete transceiving (like using 12BE6 and the like for heterodyning). Are there that many people still even using Collins gear or are they mostly just benchwarmers (well, that would be a misnomer, if they were warming the bench, they're being used!!!)

Definitely a lot of people still using them for hifi audio, but I kind doubt that the "tube effect" gets much notice when amplifying audio that just came out of an SSB decoder with 4KHz LPF... Then again, tube audio gets lost from me as I have not heard much tube output from anything other than from a class A 50C5 or 12V6 (with 12AV6/14GT8 preamp).
 
Joined
Feb 6, 2007
Messages
5,880
Location
175 DME, HEC 358° Radial
#31
A lot of guys have a boat anchor station, along with their more modern station. I know as guy with separate Collins A line, S line, and an old AM broadcast transmitter, as well as Elecraft K3 stations, each occupying separate rooms.

So, yeah, people like their tube gear.
 
#33
Anyone looking for an in-depth view at the history of vacuum tubes, here is a reference;

Full text of "70 Years Of Radio Tubes And Valves"

I have this book and often cite it in my talks- I just found out that's its online......

"70 Years of Tubes and Valves" by John W. Stokes (1982)

Its not a short book to read- but it is entertaining as well as informative- So unlike almost all technical stuff.
He explains not only the history of tubes, but little asides; things like why diodes are called diodes... (there is a definite value to a classical education :) )

Something to pull out online on a cold, snowy evening beside a fire



Lauri :sneaky:
 
Joined
Dec 22, 2013
Messages
2,824
#35
Some decade ago, the US Navy realized that microwave vacuum tubes were not going away soon and invested heavily in support of academia and R&D. There was a solid state microwave oven designed a while back, but I have not seen any advertised. The simplicity of an oven magnetron cannot be beat. Even the specialized tubes are pretty simple in construction.

Lori's post #23 TX Picture has a sort of Caveman/Cavewoman "Ogg make fire" warmth to it. I am sure there was a sort of primal satisfaction when it was first turned on. Try that with those boring solid state PA's that either work first time, coolely and silently, or burn a huge hole in your wallet when they don't.
 
Joined
Apr 9, 2018
Messages
241
Location
CO, USA
#36
Yeah, the solid state microwave oven is still not cost effective, magnetrons still got it beat. If it were cost effective, hooray, need a new transmitter final? Just buy a microwave and harvest :D Would be a lot of happy hams if there were cheap SS microwave ovens :)

I was also wondering about those cold snowy evenings, forget the fire, just get someone to start calling CQ on a legal limit tube RF PA.
 

VK3RX

Member
Premium Subscriber
Joined
Feb 24, 2013
Messages
159
Location
Australia
#37
Speaking of tube radios, I recall reading with the first Gulf War that the U.S. had to send over some Collins R390A receivers, because the front end and microprocessor circuits of some of the modern solid state gear didn't take kindly to all the high static electricity in the desert environment.

Many references via Google to this, but I've not seen anything official.
 
Joined
Dec 22, 2013
Messages
2,824
#38
Speaking of tube radios, I recall reading with the first Gulf War that the U.S. had to send over some Collins R390A receivers, because the front end and microprocessor circuits of some of the modern solid state gear didn't take kindly to all the high static electricity in the desert environment.

Many references via Google to this, but I've not seen anything official.
I worked with a Ham who was previously an employee of Saudi Aramco. He said the dust storms were heavily charged and also disrupted microwave paths.

Sent from my SM-T350 using Tapatalk
 
Top