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Re: [TenTec] New Jupiter on its Way _ A Few Questions

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] New Jupiter on its Way _ A Few Questions
From: K8JHR <jrichards@k8jhr.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sun, 27 Apr 2014 21:32:06 -0400
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Maybe... I have found that not all switches are created equal. The less expensive ones lack sufficient isolation. You want one with at least 60 and maybe 70 dB isolation - better, if possible, but I am hard pressed to say what model that would be.

I do know some guys use a time sequencer and/or an automatic receive antenna switch to kill the receiver preamp or isolate the receiver antenna when transmitting, but I would have to research them for this particular application. DX-Engineering sells one:

http://www.dxengineering.com/parts/dxe-rtr-1a

The time sequencer can be seen here:

http://www.dxengineering.com/parts/dxe-tvsu-1b


A quick email to DX-Engineering should answer whether or not it would work with your rig and transmit antenna arrangement - it would be the same answer for the Wellbrook loop as for their own active receive antenna like I have.

Also they sell KD9SV Products SV-FESSS Front End Savers are designed to eliminate the possibility of blowing out your receiver's or transceiver's front end.

Front End Savers interrupt the receive antenna to receive antenna input connection when the QSK-capable T/R line is keyed by the transceiver's amplifier keying line. See it here:

http://www.dxengineering.com/parts/svp-sv-fesss

================= JHR  ========================




On 4/27/2014 8:39 PM, ny6p01@gmail.com wrote:
On Sun, Apr 27, 2014 at 08:29:25PM -0400, K8JHR wrote:

        

On 4/27/2014 5:05 PM, ny6p01@gmail.com wrote:
    Only
problem is that I plan on employing it on the same mast with the
transmitting antenna. Is that bad practice? The reason is that I am not
allowed an outdoor antenna, and I live in a small flat.



        ER... um... maybe.   Even Wellbrook says one should
        locate it away from strong transmit antennas to
        avoid overloading the receiver input.

        I think the correct answer is that it all depends
        on how well you isolate the receiver input from
        the transmit antenna and whether or not you use
        a separate receiver from the transmit radio, and
        similar considerations.  SO2R installations have
        similar issues - sometimes guys use a "front end
        protector" as is reviewed in QST this month, and
        other guys use a "time sequencer" to kill the \
        antenna when transmitting, tied to the PTT line
        and still others use a separate receive-only
        antenna input on the rig, as is available on the
        Omni VII, but not the Eagle.

        Yep... This COULD be a serious concern if not
        fully thought out.
        

        BUT YOU COULD TRY IT AND SEE HOW YOU LIKE IT
        AS A RECEIVE ONLY ANTENNA AND DEAL WITH THE
        TRANSMIT LOGISTICS LATER...

Would a dual position coax switch take care of all this?

Lee
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