[Swan] 250C

[Greg]

Maybe it's time you looked at the AVC circuit for the receiver section. 
Malfunctioning AVC circuits can make an otherwise sensitive receiver seem 
flat.
If you're unsure about how to do that there are plenty of people here 
willing to help you.
If you are detecting .5 uv from the URM 25, the receiver is probably ok in 
the sensitivity department. Suggest you map out the AVC circuit and start 
disconnecting it stage by stage and look for sudden changes in RX 
performance.
What's the S meter doing as you go from a weak to really loud signal?
Greg
WA7LYO
Kinston NC
----- Original Message ----- 
From: <n4tua at aol.com>
To: <swan at mailman.qth.net>
Sent: Friday, July 27, 2007 3:24 PM
Subject: Re: [Swan] 250C


> Glen,
> I do have a signal generator. URM-25? and the 250C does not hear the 
> signal very well. I am using about .5uV with 30% modulation and can just 
> make out the signal as audible. Maybe I am not using enough signal. When I 
> go up to say 5uV there seems to be little change in audio output. The 250C 
> sure hears that whatever it is signal from my TS-140S receiver. I think I 
> will take the frequency counter and sniff around the Kenwood and fine out 
> what frequency that is and about how strong it is. I am stumped this time.
> Thanks, Collin
>
>
> -----Original Message-----
> From: Glen Zook <gzook at yahoo.com>
> To: Discussion of equipment manufactured by Swan <swan at mailman.qth.net>
> Sent: Fri, 27 Jul 2007 11:19 am
> Subject: Re: [Swan] 250C
>
>
>
> You really need to get a signal generator with a
> calibrated output. There are quite a few older
> tube-type generators that can be obtained for under
> $100 that work quite well (some "well under").
> Generators like the Measurements Model 80, the HP 606
> and 608, military URM-25, URM-26, TS-497 series, and
> so forth can be found fairly easily.
>
> You are going to just "chase your tail" trying to
> determine the sensitivity of any receiver without
> having the proper test equipment.
>
> Glen, K9STH
>
>
> --- n4tua at aol.com wrote:
>
> I still continue with the 250C. It seems deaf but is
> it really? I have been doing some A/B testing using
> the Swan 250C as (B), and the Kenwood TS-140S with a
> homebrew 6 meter converter as (A). The Kenwood hears
> very well I think but the 250C does not seem to hear
> any signals yet. I have check about everything I know
> to check and the receiver seems to be correct. Still
> no signals OTA. I did notice that while A/B testing
> that the 250C picks up a signal +10db over from the
> Kenwood. When the Kenwood is at about 10.239mhz the
> 250C hears a loud signal at about 50.045mhz. Not sure
> what this is but it is coming in through the antenna
> on the 250C. With the coax disconnected and a wire on
> the antenna connector the signal increases. Any
> ideas?
>
>
>
>
>
>
>
>
>
> Glen, K9STH
>
> Website: http://k9sth.com
>
>
>
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