The AM Forum

I have recently obtained a couple of the above transmitters which use a P 290A tube in the final driven by a couple of 4CX350A which in turn was driven by a single 4CX350A. The driver was all solid state but has been butchered beyond repair. The rig has two separate PA compartments which are switchable from the front panel but which use the same PA tube. All tuning capacitors are vacuum fixed types and tuning adjustments are done with the aid of two rotary inductors (heavy) in each compartment. I believe these were used for MARS purposes on Kwajalein Atoll here in the Marshall Islands but cannot find any info at all about them. All anyone has been able to say is that they were de commissioned in about 1985. As the TX was meant to operate as a linear amplifier and the range covers from 2 to 25 MHz I am looking at the possibility of using one of them on AM and keeping the other for spares. I have learned that the rig is intended to have an output of 5 KW and at the rear has a directional coupler with Bird inserts with the forward slug calibarated for 5 KW max and the reflected for 1 KW max. Has anyone got any info about this rig please? I would really appreciate any information whatsoever as I do not have any manuals or schematics. All of you ex MARS types out there, one of you at least must have met this rig, how about the guys who used to work on Kwaj or ex military types? 73 and thanks in advance. Rev Dr Bill Burton V73WJ.

I have two of the bigger Granger transmitters, the Model 272-6, uses a 100 w solid state driver into an 8794 (Burle) tube.
Similar construction, so was probably constructed the same period (mid-1970's).

Granger was an export of Bauer/Sparta div. of Cetec group.

73DG

More info at:
https://sites.google.com/view/ww2secretradiostation/introduction

I thought that looked like it had a family resemblance to a Bauer 707!