[1000mp] Hum on phonepatch input-FT-1000MP

[Ronald Walters]

Thanks Jim, I have the same setup but without the 470 ohm resistor across
the input to the patch plug.  Will give that a try, thanks again

Ron - W4LDE

----- Original Message ----- 
From: "Jim W7RY" <w7ry at centurytel.net>
To: "Ronald Walters" <rwalters8 at cfl.rr.com>; "All about Yaesu 1000mp"
<1000mp at mailman.qth.net>; "Yaseu Users Group" <yaesu at mailman.qth.net>;
"Ft1000MP Users" <1000mp at qth.net>; "Ft1000MP" <1000mp at mailman.qth.net>
Sent: Monday, November 22, 2004 20:56
Subject: Re: [1000mp] Hum on phonepatch input-FT-1000MP


> I just hooked mine up for a contest voice recorder to use with my Writelog
> contest logging recorder.
>
> Here is what I ended up with.
>
> 100 ohm resistor across the output of the sound card. Then 10K ohm
resistor
> in each leg. Then a Radio Shack 1:1 transformer. Then a 470 ohm resistor
> accross the output of the transformer and onto the phone patch input of
the
> radio. Built it on a piece of Radio Shack perf board.
>
> No hum. I do have a little RF getting into things when I run 1500 watts.
> Have not trouble shot it yet though.
>
>
> I hope you can decipher that.
>
> 73
> Jim W7RY
>
>
> At 05:14 PM 11/22/2004, Ronald Walters wrote:
> >The soundcard software program that I occasional run needs USB,
> >it is MT63 by IZ8BLY, unfortunately my old MP does not have the CPU
upgrade
> >that allows for the packet mode USB but only LSB.
> >
> >For the record I use the packet input for all other soundcard modes and
they
> >work great without any hum, however if I use the phone patch input on the
> >back of the MP I can hear some hum.  I am using isolation transformers
for
> >all inputs to and from the MP to the computer.
> >
> >Question?  Does anyone know if there is a load requirement for the phone
> >patch input.
> >
> >I am using a Radio Shack 1:1 isolation transformers, any suggestions?
> >Should I isolate the transformer with a cap?  Any parallel resistor
network
> >required?
> >
> >Ron W4LDE
> >
> >
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