[Yaesu] Re: Problem with swr readings on FT-1000MP V

Mon, 11 Mar 2002 08:27:58 -0700

Gentlemen:
    I am test driving a new FT-1000MP V for a friend and found that the
digital swr meter is NOT working correctly showing swr  even when connected
to a perfect dummy load (Bird) as it will show at least 1.5 to 1.0 when in
fact the swr is 1.0 to 1.0!!!!!!!!! Since I do not have the service manual
for it, I have not been able to make sure that it is calibrated  properly.
Sounds like this is a common problem with that particular model of radio. I
also found that the PROCESSOR readings appear to be on the low side as I can
barely get 10 db of compression with the compressor control cranked all the
way up. I own a FT-1000D and have no problems with accurate readings with
it.
    Best of 73's from Fern

----- Original Message -----
From: Joe Subich, K4IK <[email protected]>
To: Pawel, SP7PS <[email protected]>; YAESU Reflector
<[email protected]>; FT-1000MP Reflector <[email protected]>
Sent: Monday, March 11, 2002 07:12
Subject: RE: [Yaesu] SWR Meter and FT-1000MP


>
>
> > ----- Original Message -----
> > From: "Pawel, SP7PS" <[email protected]>
> > To: "YAESU Reflector" <[email protected]>; "FT-1000MP Reflector"
> > <[email protected]>
> > Sent: Sunday, March 10, 2002 6:56 PM
> > Subject: [Yaesu] SWR Meter and FT-1000MP
> >
> >
> > I put 50 Ohm dummy load instead of antenna and made a test. And it was a
> > big  surprise for me to see difference between MP's SWR and external
YAESU
> > YS-60 SWR meter. First I tried with 50 Watts and external SWR meters
> > shows 1:1.  But MP shows 1:1.3. So I increase the power to 100 Watts and
> > external SWR meter still shows 1:1.0, but internal rised to 1:1.7. Is
> > that something wrong with my MP?
>
> Pawel,
>
> It is possible that the SWR bridge in your 'MP is not properly balanced
> (nulled).  Most of the Breune type circuits have a trimmer capacitor
> in a capacitive voltage divider connected from the center conductor of
> the line.  If the bridge is not properly balanced, some forward power
> will be interpreted as reflected power yielding an incorrect (and
> variable) SWR.
>
> 73,
>
>    ... Joe, K4IK
>
>
>
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