http://elecraft.85.s1.nabble.com/Elecraft-XV144-and-XV50-TX-Noise-and-birdie-tp376803p376804.html
> Hello all,
>
> A few months back I put together the XV144 and XV50 transverters. Both
> work fine but following some comments from very local stations I decided
> to make one or two checks.
>
> I am comparing these tranverters with my own original 144Mhz transverter
> which I built about 15 years ago.
>
> With no input to either transverter but with the input terminated at 50
> ohm and with a resonant antenna connected, listening on another receiver
> with an antenna connected reveals quite a high hiss or mixing noise when
> the PTT line is operated. This happens on both the 50 and 144 Mhz
> transverters. If I operate the PTT line of my old home brew transverter
> there is no such noise or if any it is very much reduced. I am sure the
> hiss (phase/mixer noise) is many db down on the normal output level but
> it is nevertheless much greater than my original home made unit.
>
> Secondly, and somewhat more worrying is a drifting birdie that both the
> XV50 and the XV144 produce. Once again I know these are many db down on
> the normal output but the 144 Mhz birdie is of sufficient strength that
> a station 15 miles away heard it whilst trying to work an EME QSO. It
> drifted across the frequency he was using. On my particular transverters
> these birdies occur at about 50.130 Mhz on the XV50 and about 144.140
> Mhz. They seem to drift LF during TX and at a rate of about 10 Khz in 5
> minutes.
>
> I wonder if anyone else has made any observations and come up with a
> cure. I all other aspects the transverters are excellent and totally
> stable. Indeed, the 144 Mhz version is fitted with a crystal oven.
>
> I know there was a thread on here a month or two back regarding phase
> noise being heard by stations within a 20 Km radius during high levels
> of 144 Mhz activity.
>
> Has anyone else got any more comments or observations to make. I know
> that my observations are not exactly 'scientific' but there are made by
> comparison with a different transverter which does not exhibit these
> problems. During all these tests the transverters have had their inputs
> and outputs correctly terminated with no 28 Mhz drive source connected.
>
> Sorry for the long waffle. Any comments most welcome.
>
>
> Best 73,
>
>
> Ken G3WCS.
> --
>
> Ken G3WCS
> IO83rh : Cheshire : NW England
> (+44) (0)870 765 1632 (home)
> (+44) (0)7733 400 950 (mobile & sms)
>
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