[ARC5] Why "Noodling" About Sweep Tubes

[Scott Johnson]

The ultimate version of this family is the 8643, more dissipation than the
5894, designed to be conduction cooled.  Used in the high power versions of
the Motorola Motrac VHF mobile..  Neither the 5894 or 8643 could be used at
UHF with full ratings, so most UHF applications used the 8072 cermet tube.
I have seen all of these tubes last 20 years in repeater service.  BTW, the
5894 was used in the Collins 17L3 and 17L4 aircraft transmitters.

Scott W7SVJ

-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of Jim Wiley
Sent: Wednesday, October 23, 2013 7:55 PM
To: Ken Gordon; Dennis Monticelli
Cc: Arc5 at mailman.qth.net
Subject: Re: [ARC5] Why "Noodling" About Sweep Tubes

The much better version of the venerable 829A, that fits the same socket and
runs from the same voltages, is the 5894A (also known as the QQV06-40A and
AX9003A).

Also inexpensive, because not many people know what they are, particularly
when labeled using the European numbering system. Puts out more power than
the 829B, mostly because it was designed from the ground up as a VHF dual
power tetrode,  so it is a bit more efficient.

  I built a HF rig using one and got around 150 watts output, 160 thru
10 meters.  Used another in a Johnson-Viking 6N2 and got an easy 110 watts
AM, 140 watts CW output. The 5894A works at full power up thru 180 MHz and
at reduced ratings thru 450 MHz.


- Jim, KL7CC


On 10/23/2013 6:21 PM, Kenneth G. Gordon wrote:
> On 23 Oct 2013 at 18:36, Dennis Monticelli wrote:
>> I just remembered another tube. The 829B was very expensive in the
>> WW2 era but it's practically free at the hamfests now. You find them 
>> mil grade NIB. I don't think I paid more than $2 for mine. You can 
>> parallel the two tetrode sections or use them push-pull. I think 
>> they're good for 40W plate per section. 12V heaters and a 7 pin 
>> socket (Septar?) that is worth more than the tube.
> The 829B is one of my favorite tubes. The pulse version is the 3E29. I 
> buy them as often as I see them for under $5 each. They will output 
> something like 100 watts at 2 meters. They are, essentially, a pair of 
> 807s in one envelope with far shorter interconnecting leads, and 
> reduced plate dissipation rating since you can't really have 70 watts 
> PD in that small an envelope. They make a magnificent push-pull 
> oscillator in addition to being an excellent push-pull amp. Ken W7EKB

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