[ARC5] Command Sets Manuals

[Brian Clarke]

Hello Rich,

 

Even though you say you'll only use one receiver at a time, how do you
intend getting the 28 Vdc fed to it and audio out? If you solder wires into
the sockets on the rear panel, you'll reduce the resale value immensely. It
would be better for you to find a single-stall receiver rack.

 

Rather than seek the correctly nomenclatured transmitters (T-19 / ARC-5,
T-22 / ARC-5, BC-696, BC-459), if you get a BC-457 (4.0 to 5.3 MHz)and a
BC-458 (5.3 to 7.0 MHz), you can adjust them internally to work on the bands
you want. You need to adjust the padder capacitors and slugs associated with
the VFO and output sections. A more thorough-going modification would be to
change the VFO and RF PA coils as well, though for restricted frequency
range use, this isn't strictly necessary. The frequency dials won't read
correctly, but there are solutions - ask here for the correct dials, or draw
up a look-up table or graph showing what frequency you get for each
frequency setting. For instance, on the BC-457, you might set the dial at
4.0 MHz and adjust the padders to give you 3.0 MHz output, and then wander
up the frequency band noting what markings correspond to specific
frequencies. To do this properly, you set the VFO first and then dip the
output section. To meet the FCC's (and other jurisdiction's) regulations,
you can't rely on dial settings; you will need some means of independent
verification of your output frequency, such as a counter.

 

Going down this path of modifying the BC-457 and BC-458, will cost you much,
much less $$ than seeking the BC-696 and BC-459. The BC-numbered
transmitters were designed for screen modulation. Maximum RF power output
about 12 W. Initially, during WWII there was no call for 3 to 4 MHz by the
army; that demand came in later. Consequently, the BC-696 (note the
out-of-sequence numbering) is less frequently found, and when found, is much
more expensive than the BC-457 and BC-458. This price differential is driven
further by lack of demand from radio amateurs for the non-ham-band
transmitters.

 

The ARC-5 transmitters are even rarer and more expensive. And the two-stall
ARC-5 transmitter racks are expensive - I've seen eBay vendors asking US$250
recently.

 

The BC-456 modulator for the BC-series transmitters is less expensive and
more readily available than the MD-7 / ARC-5 modulator; the MD-7 is designed
for plate modulation of the T-19 through T-22 transmitters. The connectors
on the racks, modulators and remote controls don't cross-match; the only
connector matches are for the 28 Vdc power input, the intercom and the
antenna changeover relay. To mix transmitters and modulators will cost you
hours in modification time, if you can find the connectors.

 

These are beautifully-designed sets that are easy to repair, and will give
you hours of fun.

 

73 de Brian, VK2GCE

 

On Saturday, 22 June 2019 1:58 PM, Rich said:

 

<snip>

 

Several list members had counseled me to keep the triple rack that the
receivers are currently occupying. My main problem with the rack is the lack
of space in/around the new shack. As it is I will probably use only one of
the receivers at a time. I figure that I can hook the radio(s) up toe 24VDC
and run them (one at a time) off of the dynamotors. 

 

Anyone have a SWAG as to what a T-19/T-22 (BC-696/459) currently cost
(preferably without me giving up a kidney or part of my liver!!)

 

Again, thanks to all who offered me info and comments. This is a GREAT
group.

 

 

Vy 73 es gud DX!


Rich Arland   K7SZ   WPE7BYR

Bent Dipole Ranch, Dacula, GA

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