Answering in line:
----- Original Message -----
From: "Mark Erbaugh" <mark@microenh.com>
To: <tentec@contesting.com>
Sent: Friday, September 17, 2004 2:11 PM
Subject: Re: [TenTec] jupiter tx / ft920 rx
> > Two questions: 1. Would I not have to put a spdt switch in that line to
> keep
> > from feeding the sig to both receivers at the same time?
>
> As I understand, you want to be able to transmit with the Jupiter and
> receive with both the Jupiter and the 920. In that situation, I don't
think
> you need an additional switch.
>
Not exactly, but it's an interesting idea... Yes: tx Jupe/rx 920 under noisy
condx. I would presume though, that feeding both receivers at the same time
would result in 3db loss as the signal would be divided in half if both
input impedances were the same value. This may be acceptable as the 920 has
abounds with RF/IF gain -- it's certainly simpler; I'll try it first. Under
normal conditions it would be Jupe/tx&rx -- in which case I could just
disconnect the line going to the 920's external rx input and avoid the
loss..
> Connect the antenna to the Jupiter SO239 input. After making the mod,
onnect
> a cable from the SPARE jack on the back of the Jupiter to the Rx antenna
> input on the 920. Just make sure that you never put an Tx RF on that
> signal, but I'm assuming that the Rx antenna input of the 920 won't let
you
> do that anyways. Under this scenario, you wouldn't have any antenna on
the
> main antenna connection of the 920 and you wouldn't be able to transmit
with
> the 920.
>
> Am I understanding your situation?
Yep... thanks
>
> > 2.) when you refer
> > to the 'gotcha', do you mean if the jupe and the 920 are on different
> bands?
> > If so, that wouldn't be a problem for me as I rarely have had occasion
to
> do
> > crossband work.
>
> Yes, that is the problem since the Jupiter's LPF is inline.
>
> One other thing you may want to do is to mute the 920 audio when
> transmitting on the Jupiter. While the Rx antenna is greatly attenuated
from
> the Jupiter's RF output, there will probably still be significant signal
> getting to the 920. Does the 920 have a mute input?
If the tx RF sig from the Jupe leaking into the 920 is not overwhelming, I
could use it to monitor my sending, negating the necessity to mute the
receiver. The 920 doesn't have a mute input.
Thanks for the help and I'll let you know how I make out in the next few
days.
Jerome -- VA7VV
>
>
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