[NLRS] Question -- 2m transverter (30w) driving higher band transverters

[Jim Froemke]

Ray, both of my DEMI 222 Xverters sometimes go into self oscillation when
the PTT is active (even with everything terminated in 50 ohm). The first
time it took out my 222 amplifier finals. Steve spent some time looking at
the Xverter but couldn't recreate the problem. The fix I use is to run a
wire from TXON bus to the NC position of the K1 relay (assuming the Common
connection of the relay is grounded). This keeps the TXON bus voltage from
building up while you're receiving do to leakage of some yet undefined
component. You can do this test: monitor the TXON voltage while you're in
receive mode and check to see if it's increasing over time.

73, Jim
K0MHC
EM00

-----Original Message-----
From: nlrs-bounces at mailman.qth.net [mailto:nlrs-bounces at mailman.qth.net] On
Behalf Of Ray J
Sent: Friday, November 06, 2009 9:54 PM
To: NLRS at mailman.qth.net
Subject: Re: [NLRS] Question -- 2m transverter (30w) driving higher band
transverters



Hope the PA never decides to oscillate

My dem 222 transverter would put out full power at times with no drive 
at all.. I had no idea what frequency that it was transmitting.. think 
it must have been a bypassing problem..

Ray J


Bill Davis Jr wrote:
> 
> 
>   A question out there for you rover builders, I would guess. I have done
a major rebuild here and "AFTER THE FACT" have a question. I am using a 35w
DEM 2m transverter to drive my 902, 1296 and 10Ghz transverters. This is a
new configuration here. In the past these were driven at different times a
Kenwood TS700, a Yaesu 290R II and a 28Mhz Softrock/DEM transverter
combination. With the new setup I have been successful with obtaining good
drive levels using the power settings on the IF rig as well as pads and DEM
drive adjustments.
> 
>   The question is ... I am running the 35W DEM transverter at a watt or 2.
This is VERY low in it's dynamic range. Will I have degraded linearity or
some other "sleeping dog"  issues due to this? So far not any Qs other than
on "non-transverter" bands. Oh a Q with KB0CIM on 2m, but I am fighting an
issue with that TX chain at the moment.
> 
>   For almost 10yrs I  used my Icom 735 (100w HF rig) at reduced power
control settings to drive my 6m and 222 transverters with good sig reports
and no know issues. I was running at a VERY LOW power setting. I would think
even lower percentage wise than the DEM transverter.
> 
> Thanks .... 73  Bill   K0AWU  EN37ed
> 
> 
>  		 	   		  
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