[ARC5] T-11 Crystals

[Tim]

Hi Bob -
I have a T-13A/R-19 going on 2 meters AM, by way of comparison...
http://www.n6cc.com/type-12-vhf-am-aircraft-system

Didn't have any crystals (or knowledge) specified by the original ARC
crystal specs....

So I used an FT-243 crystal on 8025 KC to try to put it on 144.450 MC.
(18X, with a DIY pin adapter). In the stock circuit, it transmitted at
144.437 MC.  So I brought the grounded pin of the crystal to ground via a
parallel combination of a 20 pf silver mica and a 2.5-23 pf ceramic
variable cap. I can tweak it right to 144.450 MC at the antenna and it has
been working fine.  We are using that freq in the San Fran bay area for
experiments. (The APRS digipeaters are killing us on 144.390 BTW)  These
receivers are pretty broad!

73, Tim
N6CC

On Sun, Feb 10, 2013 at 6:20 AM, Robert Eleazer <releazer at earthlink.net>wrote:

> I have a few ARC T-11 transmitters and in a moment of unusually intense
> insanity last night decided I should try to put one on the local Unicom
> frequency, 122.975 MHZ, and power it up in my hangar, so that I could ...
> well, just because.
>
> I dug out my TM 11-525-25, the US Army maintenance instructions for radio
> Set ARC Type 12, and tried to figure out what crystal I would need.
>
> It says that the crystals operate in a Pierce circuit at either 1/12 or
> 1/18 of the operating frequency and are ARC-14958 which supersedes
> ARC-10714.
>
> Okay, so do I find a crystal for 1/12 or 1/18 and what does that ARC part
> number translate in terms of CR or HC numbers?
>
> Thanks
>
> Wayne
>
>
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