Barker & Williamson Input Inductor Asssembly

[W7SOE]

I am working on a schematic of the RF deck of the "new" transmitter.

The RF input tuning circuit includes a beautiful air-wound inductor/switch assembly made by Barker & Williamson.  It consists of five air-wound coils mounted on a wafer switch.  The front plate has markings for five bands/frequencies.

The unit is marked:  BTCL 3817 10-80  (10m-80m I assume)

Does anyone have any documentation on this?  It would help me draw the schematic without having to take it too far apart.

73

Rich

[W7SOE]

Thanks Mack, perfect!

I still think it is beauuuutiful.  ;-)

Rich

[The Slab Bacon]

I gave one of those to the Vortex a few years ago.

IIRC they made several styles of those turret coil assemblies. the choice was center link, or the coupling link at the "high" or "low" side of the main coils. They could be used for link coupled plate coils or turned around backwards for link coupled grid input coilz.

                                                   The Slab Bacon

[Carl WA1KPD]

I gave one of those to the Vortex a few years ago.

IIRC they made several styles of those turret coil assemblies. the choice was center link, or the coupling link at the "high" or "low" side of the main coils. They could be used for link coupled plate coils or turned around backwards for link coupled grid input coilz.

                                                   The Slab Bacon

Frank,
Having visited the Vortex museum last week I seem to recall that hanging right at the stairs as you head out of level 1.It caught my eye because I have 3 sets of em. Two are in one HB 6l6/807 transmitter. One for the "driver" and one for the "PA"

[W3SLK]

Yeah, I got two of them still in the neat little red boxes

[k4kyv]

Yeah, I got two of them still in the neat little red boxes

Have you checked them lately to see if the air-core coils have self-destructed yet?  The plastic insulation over time will shrink and then turn to dust, leaving the coils all distorted out of shape and eventually with the turns loose and dangling unsupported.  Sometimes the shrinkage is enough to actually break the ceramic bars on plug-in coils.  It could possibly damage the switch wafers on the turret assemblies.  I have seen the disintegrated insulation actually break into flames when rf is applied to the coil.