811 home brew
 

I've been playing around with tube equipment since I was 17. I'm now
21 and building an old school transmitter. I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

I'm hoping to have it finished by the spring, I have the power supply
finished and I look forward to starting the transmitter

811 home brew
 

On Wed, 17 Oct 2007 23:05:12 -0700, pinball_wizzard_01
wrote:
I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

Congratulations on your project. If you need any help with parts or
whatever, just let us know, you never know what might be overflowing
out of some hams junkbox and just what you need.

Rick K2XT

811 home brew
 

On Wed, 17 Oct 2007, pinball_wizzard_01 wrote:

I've been playing around with tube equipment since I was 17. I'm now
21 and building an old school transmitter. I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

I'm hoping to have it finished by the spring, I have the power supply
finished and I look forward to starting the transmitter


You didn't tell us what bands this was going to be for. Higher frequency
might need neutralizations.

2x811 in push-pull? Probably grounded cathode, but you didn't mention that
either. It is possible to run grounded grid push pull, but it's rare.

811 home brew
 

pinball_wizzard_01 wrote:
I've been playing around with tube equipment since I was 17. I'm now
21 and building an old school transmitter. I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

I'm hoping to have it finished by the spring, I have the power supply
finished and I look forward to starting the transmitter

Pictures? If you have a web site, or if you can post to one of the
public picture sites, that would be very cool.

I'm twice your age and haven't gotten around to building a tube
transmitter yet, although I've rehabilitated some SSB tube gear and used
it on the air. I hope to make something from scratch before I keel
over, but it may have to wait for retirement, or at least for the kids
to get off to college.

Good luck to you!

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

811 home brew
 

Jimmie D wrote:

If you really want it to look impressive build it on some old telco open
frame racks.

That's too high tech. I built mine on plywood and Masonite.

There is a writeup of my 811 project at http://schmidling.com/radio.htm

I need to update it but you will get the idea.

It is a single 811A modulated by a pair of them using two separate power
supplies. Both supplies, RF Deck and Modulator are on wood. The only
aluminum chassis is the VFO Exciter.

Complete with CBS Audio Chain and EQ, it is the best sounding rig I have
ever owned.

js


--
PHOTO OF THE WEEK: http://schmidling.com/pow.htm
Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com

811 home brew
 

PB Wizz:

It's great that you're doing this!

Remember that 866s need heating time to vaporize the Mercury before
applying High Voltage.
When I built the HV power supply for my "big rig," I put in a
thermostatic time delay relay (which triggered a high current relay) to
disable the plate transformer primary for about a minute, after the
filaments went on.

Good Luck & 73

afcsman--W9NPI

811 home brew
 

With those glowing fire bottles I hope that you have/will design the
layout so that you can put a glass window in the front panel to let the
glow show through,

Good luck with project - Paul

pinball_wizzard_01 wrote:

I've been playing around with tube equipment since I was 17. I'm now
21 and building an old school transmitter. I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

I'm hoping to have it finished by the spring, I have the power supply
finished and I look forward to starting the transmitter




--
Paul S. Hinman - VE6LDS
long West 113 deg 27 min 20 sec
lat North 53 deg 27 min 3 sec
Maidenhead Locator DO33gk

811 home brew
 

pinball_wizzard_01 wrote:
I've been playing around with tube equipment since I was 17. I'm now
21 and building an old school transmitter. I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

I'm hoping to have it finished by the spring, I have the power supply
finished and I look forward to starting the transmitter

Just a query. Is there any particular reason why you are using the 866's
in parallel?
Remember a half wave rectifier puts a lot more strain on your HT
transformer. Perhaps though you don't have a centre
tap on your secondary winding! Also if you had 4x866's in a bridge
circuit you would need an awful lot of heater windings.
Many years ago I built a parallel 811A grounded grid linear amplifier
which worked quite well but of course with directly heated tubes you
need a really beefy filament choke!!!
Best of luck with the project and remember to always keep a hand in your
pocket while playing with 1500 to 2000 volts.
Regards Cliff Wright ZL1BDA ex G3NIA