829B Dual Beam tube

[KB7HTV]

do the tube tables tell you the output for only one side of this little baby
of are the numbers assuming using both plates in parallel?

Does anybody know

[The Slab Bacon]

Most of the time the ratings are for both sections in parallel for RF ratings (Class C) or both sections in push-pull for audio ratings (Class A, B, AB1&2). look at the tube chart closely, sometimes they will have subnotes denoting the type of service and whether or not they are for both sections combined.

If there are no subnotes, it is most likely that the ratings are for both sections combined.


It would be pretty cool to see someone build something with some 829-Bs. They are still plentiful and absolutely give away dirt cheap at hamfests!! 1 in parallel modulated by one in push-pull would probably make for a pretty compact 100w carrier table top rig!!

[WU2D]

The 829B is capable of respectable power even though its combined plate dissipation is similar to an 807. You can run it at a full 100 Watts input power even up to 2 Meters. I used one in the final of a 10M AM homebrew at 60W input power and modulated it with a pair of 1625's but there is no reason why you could not use another 829B as the modulator. It does take a lot of grid drive (2 Watts) compared to most modern dual power tubes however and that is why the tube fell out of favor with the mobile radio people. You need something like a 5763 or 2E26 to drive it at VHF.

[W9GT]

Hey Slab,

I agree about the 829B.  I have a neat home brew transmitter that was given to me that I need to get on the air.  It was probably built in the late 40's and has an 829B in the final that is plate modulated by an 815.  It is quite large for a 75-100 watt rig (takes up a whole 4'  short rack cabinet).  

Very interesting combination using two dual beam power tubes.  The 829B is still very common/plentiful and is really often overlooked as a great choice for low/medium power.  The 815 is not so common, but makes a nice modulator in the 50 watt range.  

The transmitter uses the old B&W plug-in coils and is presently on 10 meters, but should be easy to get on all bands.  I just need to move it up in the pending projects queue.

73,  Jack, W9GT

[WQ9E]

Johnson built some of the Viking 1 transmitters with an 829B instead of a 4D32 because of a shortage during the early days of the Korean conflict.  One of my Viking 1 manuals has an errata note about this substitution and the AM input rating is slightly lower when using the 829B tube.

[The Slab Bacon]

Jack,
        just FWIW, the 815 is a pair of 2E26s in one bottle. With both sections on P-P,
500v on the plates and enough drive to push a little grid current (AB2) they will easily make 50w of audio.

IIRC, the 829B with 700 - 750v on the plates will get real close to 100w. Both are neat lookin, under utilized tubes! ! ! !

[KM1H]

The 832 (the first of the family), 829 and other versions were generally rated in the manuals for PP in audio and RF and a footnote indicated the numbers were for both sections. There was very little parallel operation except for the stop-gap Viking I fix and occassional ham use. There were Motorola 2 way FM rigs using the 5894 and others well into the 90's and then into ham repeater service. Those were all PP operation.

There were also several ham transmitters, TX converters, and transverters using a PP 5894. Its also a decent SSB linear tube.

Carl

[The Slab Bacon]

Carl,
       I have some older Motorola stuff (mostly low & high band) that used both 5894s and 8643s in parallel. (Mostly Motrac era) they had a big round slug of aluminum for a plate cap that had holes for both plate pins and small allen setscrews to clamp them down. Now, the UHF stuff was push pull.

[KM1H]

Yep, when the output C didnt kill you it saved a few pennies that way. Hallicrafters ran PP even on 6M and so did the Johnson 6n2. PP gets rid of that nasty 2nd harmonic better on 6M and plus a filter you dont take out part of the FMBCB or VHF highband with the 3rd harmonic.

The WW2 VHF ARC-5 also ran PP with the 832A's and the first thing hams did was stuff an 829B into the output stage.

[KB7HTV]

Thanks guys, I was thinking of using this tube modulated by a pair of 6146B's
but the suggestion to use another one as a modulator in push pull is outstanding

I want to use a line level input transformer to grids from a modern tube pre
(because I allready have the pre-amp) because it has phantom power
for the sennheiser

cool suggestion though on the modulator

HTV

[W2PFY]

My thought is to build a rig using 829B's in push pull parallel. You could get about 200 watts output. Maybe mod it with 4-809's in push pull parallel using zener diodes for bias on the 809's.  I have all the parts to build it for 80 through ten using a MB 40 in the osc stage and and MB 150 in the final. No band switches used in this circuit. Does anyone remember where to find that circuit? It may have been in an old QST?

[John K5PRO]

The first tube amplifier I played with was a Millen using 829B on 2 meters. It was wide open, RF leakage everywhere, but had that neat tube in it.

[KM1H]

I built a 6M AM rig with one in PP in 57, mod by 6L6G's. Whatever the power was it was enough to work all over the US and some Caribbean/SA during Cycle 19's peak years. Plus Ireland and some 10M crossband into other parts of Europe. Antenna was a HB Handbook 4el at about 20' high on a 2nd hand TV rotator. Those were fun days.

[W1ADR]

Appreciate seeing the continued interest in both the 829B and 832A tubes. My experience with both of these tubes goes back to WWII when I was a radio repairman in the Signal Corps. The 829B's were used in the transmitter units of Our AN/TRC 3 VHF (70-100 Mhz) ground telephone/teletype field communication link equipments with the 832A's used in the SCR-522 UHF (100-156 Mhz) aircraft communications set. The performance and suitability of both types were demonstated during the service usage of their respective equipments, particularly for the 832A's because of the wide range of altitudes  and temperatures encountered in it's flight aircraft application. For sheer simplicity, their commonality in basing allows for a basic test set-up with which one can evaluate the suitability of either type for his intended application.

[KB3DKS]

I built a 6M AM rig with one in PP in 57, mod by 6L6G's. Whatever the power was it was enough to work all over the US and some Caribbean/SA during Cycle 19's peak years. Plus Ireland and some 10M crossband into other parts of Europe. Antenna was a HB Handbook 4el at about 20' high on a 2nd hand TV rotator. Those were fun days.

Carl,
Do you have that 6m trans circuit or can you point me to a handbook with it?
Couple years ago picked up a rough homebrew 6M AM trans that used a PP 829B with a pair of 5881s mod and a 2? meg VFO doubled. The VFO was built nice, link coupled under chassis but basically unshielded. Common audio circuit with a pair of 12AX/AU7s and what looked like a rebuilt, gapped, stancor or thordar 2 tap secondary 50 watt mod tranny. Had a mixmosh of Iron and strapped on oil caps.
Sound like it?
Bill

[KM1H]

Mine was designed by a local engineer and I dont believe it was published. Several were built out on LI, NY using a lot of Radio Row and MARS surplus.

A 6AG7 was the 8.3 mc oscillator/tripler, a 1614 was a doubler which had more than enough drive so a pot was in the screen line.

Memory is a bit fuzzy but I believe the 6AG7 and 1614 both ran on around 275V and the 829B at 400V which was also on the 6L6's. Mod iron might have been from a TCS.

Carl

[W2PFY]

There's a lot to see when you Google the 829B

http://www.google.com/search?client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&channel=s&hl=en&source=hp&biw=1015&bih=562&q=829B+transmitter&btnG=Google+Search#q=829B+transmitter&hl=en&safe=off&client=firefox-a&rls=org.mozilla:en-US:official&channel=s&biw=1015&bih=562&prmd=ivnsb&ei=HH-HTfK-GYfkrAGC6u2zBg&start=0&sa=N&bav=on.2,or.r_gc.r_pw.&fp=ff3e2739446bc197

[ke5o]

Thanks to a repair job from my good friend Fred WA5QAQ, my SCR 522 is working great!
Pumping out 5 watts of VHF and the receiver detects below 1 microvolt.
I will be installing it in my '45 Willys AN/VRC-1 forward air control jeep.
73, Steve