[NLRS] DEM 144-28 transverter with common IF - response

[jim.k0mhc]

Jon, I didn't see any response to your question so here's my 2 cents worth.

I converted my DEMI transceivers to a common IF (28 MHz) by using a DEMI 
provided mini PCB and RF relay. It allows you to use a single "common" IF 
input and switch it between the IF-TX and IF-RX inputs on the main 
transceiver PCB. It features a high isolation RF rated relay and impedance 
controlled land patterns on the PCB. The challenge is to then switch the 12 
VDC relay together with the PTT input of the transceiver with proper 
sequence protection. The regular TX and RX gain controls on the main 
transceiver PCB are still fully operational. I recommend using mini coax 
between the two PCB boards for proper impedance control. My 6, 2, 1.25 and 
0.7 meter DEMI transverters now work fine with both my SDR1K 28 MHz IF 
transceiver as long as the IF power levels are properly setup.

I'm not sure if this mini PCB and relay combination is still listed for sale 
on the DEMI website so maybe you'll have to inquire about it.

Regards, Jim
K0MHC/RV

----- Original Message ----- 
From: <W0ZQ at aol.com>
To: <nlrs at mailman.qth.net>
Sent: Monday, February 19, 2007 8:26 PM
Subject: [NLRS] DEM 144-28 transverter with common IF


>
>
> Hello NLRS land.   Question for all  those DEM 144-28 transverter users. 
> Is
> anyone using their  transverter in a common IF (28 MHz side) configuration 
> ?
> If so, how are  you doing the combining/splitting between your IF rig and 
> the
> transverter  ?
>
> 73, Jon
> W0ZQ
>
>
> Thanks for your participation in the 2007  MnQP !
>
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