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

[K8JHR]

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 at gmail.com wrote:
> On Sun, Apr 27, 2014 at 08:29:25PM -0400, K8JHR wrote:
>>
>> 	
>>
>> On 4/27/2014 5:05 PM, ny6p01 at 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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