----- Original Message -----
From: rb <rbigg@pcola.gulf.net>
To: <amps@contesting.com>
Sent: 7. marts 2000 05:25
Subject: Fw: [AMPS] SSB interference
>
> Tom--there it is. I agree. I think the long and short of it is you have
to
> literally monitor your outgoing signal and tune off on either side to see
> how clean or dirty it is. I appreciate hearing the method of using a high
> attenuation bridging tap to get a small enough signal to avoid rcvr
> front-end overload. I have a trusty old wheezer of a BC-348 that I'll try
> to rig up to do that. Its IF is wide as a barn door, anyway, so should be
> ideal for hearing nasty things way off to either side without having to
tune
> any.
>
> When you do this, is there any problem avoiding mic feedback (the mic
> "hearing" back what is being said over it)? Any procedure or cautions
here?
> It would seem like an easy way to get feedback howl and/or rf feedback in
> the audio of the xctr/final combo.
Use a taperecorder with well adjusted output that matches your microphone.
That can talk for as long you wish. You can easily adjust the output to see
the effect. You can compare the LF-inp. to TX with output from RX on a
2-ch scope etc. The results are interresting but sometimes hard to accept.
73 de OZ5TG
> Thanks for the response.
>
> 73 de Ron, K5BDJ
>
> -----Original Message-----
> From: Tom Rauch <w8ji@contesting.com>
> To: amps@contesting.com <amps@contesting.com>; rb <rbigg@pcola.gulf.net>
To: <amps@contesting.com>
> Date: Monday, March 06, 2000 6:59 PM
> Subject: Re: [AMPS] SSB interference
>
>
> >.
> >>
> >> I don't want to ever put out a bad signal. I'm thankful that I have a
> >> means, through other hams on the net I check into, to give me a reading
> of
> >> relative signal quality. Is there a better way?
> >>
> >> 73 de Ron, K5BDJ
> >
> >Hi Ron,
> >
> >I listen to my signal on a separate receiver from time to time, that
> >is tapped off the main output line through a high attenuation
> >bridging tap.
> >
> >So far as I know, the only way to accurately measure BW is by
> >somehow looking at bandwidth.
> >
> >The problem with looking at only amplitude response is when non-
> >linearity is indicated, some shapes of non-linearity don't cause
> >IMD. To make matters worse if the distortion occurs before the
> >SSB filter, the filter will remove the IMD products! So things can be
> >a lot cleaner than an overall linearity test will indicate, if you look
> >only at amplitude linearity.
> >
> >The other problem is a signal that looks very linear can still be very
> >wide!
> >
> >The best test is to measure what you want to know as directly as
> >possible. If you want to measure bandwidth, then measure
> >bandwidth if you can.
> >
> >
> >73, Tom W8JI
> >w8ji@contesting.com
>
>
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>
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