[VHFcontesting] Keying Amplifier before the Transverter

Duane - N9DG n9dg at yahoo.com
Tue Dec 28 21:22:30 EST 2004

For the typical solid state brick and no tower mounted
preamp configuration I've had perfectly fine results
with the radio keying the transverter and then using
the AUX relay contacts of the DEMI transverter to key
the amplifiers. That way if the transverter does not
get keyed for some reason the amplifier won't either.
All of my amplifiers are hard keyed this way, I never
use the RF sensed TR switching that is typically
available with the SS brick amplifiers.

However if there are tower mounted preamps in the mix
then I would use the sequencer approach as already
suggested earlier.

I have also standardized all of my PTT keying for
everything to use closure to ground type configuration
and then add intermediate reed relays to the IF radio
connection as needed to make sure it works that way.
I'm also using these reed relays as a means to break
the DC ground path of the keying circuit between the
radio to the transverter. I do do this as insurance to
help avoid potential ground loop related RFI problems.


--- wa4kxy at bellsouth.net wrote:

> I would suggest using a sequencer.  You key the
> sequencer and then the sequencer keys the amplifier,
> transverter and finally the TS-850S in that order. 
> What you are proposing will probably work (I have
> done things like that in the past) but the sequencer
> is guaranteed to work.  DEMI sells one in a kit for
> $60 or $95 if you want it assembled.
> 73
> Jim W4KXY
> > 
> > From: "DUGAS, JASON A. (JSC-EP) (NASA)"
> <jason.a.dugas at nasa.gov>
> > Date: 2004/12/27 Mon AM 10:50:57 EST
> > To: "'vhfcontesting at contesting.com'"
> <vhfcontesting at contesting.com>
> > Subject: [VHFcontesting] Keying Amplifier before
> the Transverter
> > 
> > Hello All,
> > 
> > I am about to put my DEMI 144-28 transverter on
> the air along with a Mirage
> > 3016 amp.  The IF rig is a TS-850S.  I am using
> the 850S in a common IF
> > configuration.  I am using the relay contacts
> inside the TS-850 (pins 4 & 2
> > on the REMOTE connnector) to drive two BJT
> transistors that will in turn
> > energize relay coils for keying the transverter
> and the amplifier.  
> > 
> > My question is, if the amplifier somehow gets
> keyed somewhat before the
> > transverter or if the transverter gets keyed
> before the amplifier is there
> > any thing that can be damaged?  Are there any
> pitfalls here that I need to
> > watch out for?
> > 
> > Thanks,
> > 
> > Jason 
> > KB5URQ

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