[BC] RCA BTA5L

[Peter]

On Apr 29, 2008, at 8:07 AM, Ron Nott wrote:

> In the early 60s I worked at a station that had an RCA BTA-5F.  It  
> used 892R tubes for both PA and modulators. Plate voltage was 9  
> kV.  At the Bolack Electromechanical Museum in Farmington, NM there  
> is the RCA 50 kW transmitter that was in use at KOB in Albuquerque.

The F series was immediately post-WW-II and used 892Rs at the 5 and  
10 kW levels.

Always two 892Rs for modulators. One 892R for the final in a 5 kW box  
and two 892Rs for a 10 kW box.

A lot of these transmitters were ordered as 10 kW boxes, but with a 5  
kW final.

These could do 125 percent modulation with great ease, and were quite  
popular with the R-'n'-R stations.

The 50 kW boxes from the F series were stand-alone 50s, not linears  
with 5 kW stand alone drivers.

The 50s with the stand alone drivers were the E series.

The original writer asked about an L series, which is a much later box.

By this time, RCA was using tetrodes, not triodes like the 892R and  
that induction welder tube which RCA used in the 50s, and which had a  
three-phase filament.

The same tetrode as used in the VHF transmitters, as I recall.

Gates would use a 3-3000 series from Eimac in its 5s and 10s, but RCA  
would always use an RCA tube, if possible, and that meant one of the  
VHF tetrodes.