[TenTec] Argosy 1: birdy

[Dr. Gerald N. Johnson]

On Sun, 2006-06-18 at 16:26 -0700, D. Kemp wrote:
> Date: Sun, 18 Jun 2006 12:35:38 -0400
> From: "Mike Hyder  -N4NT-" <Mike_N4NT at charter.net>
> Subject: Re: [TenTec] Argosy I: birdy
> 
> Can you hear the birdy with a resonant antenna
> connected to the Argosy?  
> If 
> so, is it strong enough to override a very weak
> signal?
> 
> Mike N4NT
> 
> 
> 
> Date: Sun, 18 Jun 2006 12:40:27 -0400
> From: Ed <w3nr at comcast.net>
> 
> 
> As do all TT rigs thru the Corsair II. TT's advice,
> "don't operate on 
> 21.320".
> 
> Ed W3NR
> 
> 
> Mike and Ed.
> 
> On a tuned antenna it is not a strong birdy. The notch
> is effective for ssb and would work on cw if the cw
> tone is different. A weak cw sig right on the birdy
> freq may be rough to copy, but it would be easy to
> offset the receiver slightly and use the notch.
> 
> I learned something else about TT rigs. Thanks Ed for
> the info. I checked my C21 and it also has a birdy at
> the same freq but it's much louder than the Argosy.
> Is it the 9 MHz IF, or what causes it?
> 
> 73,
> 
> Don, nn8b

Its trivial. The PTO always tunes 5 to 5.5 MHz. Its mixed with 9 to get
14. Its mixed with appropriate crystals to convert 9 to other bands.
21.320 is four times 5.320 which is where the PTO sits to receive 21.320
though there maybe a 10 KHz offset in the PTO mixer crystal for 21 MHz
to move it a little. It should be present in the Orion too, unless the 5
MHz circuit is really well shielded.


-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer