[ARC5] Command Set Field Day

[Tim]

Hi Ken - Agreed on the Command Set receiver performance aspects.  That
Range Filter works quite well and is more-or-less reasonable in a setup
like mine although certainly not intended for use as a CW filter in an
aircraft..  It's 1020 cps filter peak is too high (I prefer about 800 cps
for CW), but it is "stock".  I kinda chose to keep this set fairly "stock"
except of course for the power supply and the construction but that was
mainly driven by parts availability.....  So I decide keep it that way to
"experience the original designed performance - as is".... Yep - some
simple modern circuits could be added to make it perform "better" but I've
avoided that in this case.  On the other hand:

I have done some prototyping of solid state power supplies for my ARC Type
12 VHF transmitter/receiver sets before I found the correct Dyno.  That
prototype also works well on the ARC-5/'274 receivers.  See
http://www.n6cc.com/solid-state-dynamotor
It is a mechanical/packaging kluge but it was really intended just to test
the circuitry.

But that prototype design was based upon my Junk Box inventory and may not
be easily replicated primarily because of the transformer magnetics
design.  I am also working on a 12 VDC power supply for the GRC-109
transmitter which will also incorporate the SS power supply I have already
built for the GRC-109 (and GRC-9) receivers.  Again, would not be practical
to replicate for the same reasons.  See
http://www.n6cc.com/grc-9-grc-109-receiver-battery-power-supply     No
Rocket Science here - just basic power supply design - the mating
connectors are the bigger problem!

I just received a cast metal box from a GRC-109 transmitter from Fair Radio
and intend to build the combined GRC-109 TX/RX SS power supply inside that,
instead of my usual "ammo box" packaging.  The breadboard is working,
packaging remains to be done as I find time.

I could probably lash up a solid state dyno for the SCR-274 transmitter but
will ultimately go the dyno route - I like the sound of them!

Fun stuff....
73, Tim
N6CC

On Tue, Jan 1, 2013 at 2:02 PM, Kenneth G. Gordon
<kgordon2006 at frontier.com>wrote:

> On 1 Jan 2013 at 13:29, Tim wrote:
>
> > Hi - Thanks - Yes, Amen to all of that!  A bit dicey to operate during
> > crowded conditions but perfect for casual Camp Ops...and Vintage Field
> > Day (different weekend!).  Best of all, no synthesizer, digital phase
> > noise in the sidebands and NO MENU's!  Ha..  But the Fun Meter is
> > pegged....
>
> Yes! Indeed! I'm with Mike on this one: show the ignorant how to do it.
>
> Actually, I have found the selectivity of the 80 meter receiver to be quite
> adequate under most conditions, especially if you modify the first IF for
> adjustable regeneration. This requires two pieces of #12 THHN at the tube
> socket, and a pot in the cathode circuit.
>
> A nice audio filter of some type also helps a lot. The various "Range"
> filters
> provide a pitch that is much too high (1020 Hz) for me, though. I use
> either
> the old CWF-2 filter, or the modern equivalent by Vectronics. Those are set
> to about 750 Hz.
>
> The selectivity of the 40 meter receiver is much too broad (purposely) and
> really can't be much improved on, although it is certainly fun to use.
>
> Using one or more of David's converters with a BC-453 or R-23/ARC-5 will
> work very well indeed, with plenty of adequate selectivity.
>
> BTW, Tim, I also own and operate an AN/GRC-109. I am extremely
> interested in your various home-brew inverter power supplies for both the
> ARC-5 and the '109.
>
> Are you going to be able to finish those any time in the near future?
>
> You have an excellent website, by the way.
>
> vy 73,
>
> Ken W7EKB
>