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Re: Yaesu 847 Question



Dave Marthouse (N2AAM) wrote:
 
> Does the Yaesu 847 have transverter outputs?  Any information would
> be appreciated.  Thanks.

No, it doesn't have transverter connections.  However, it can be
done in a number of ways.

The Down East Microwave web site http://www.downeastmicrowave.com has
information on transverter interfacing, including several devices in
kit or assembled form.  There are two basic ways to do it that don't
involve any modification to the FT-847.

One method uses an interface that lets your radio transmit at full
output power, and most of the power is dissipated into a 50 ohm load
resistor, letting only an appropriate amount of transmit power reach
the transverter.

The other method uses an interface that sends a negative voltage to
the FT-847's ALC input jack, which causes the radio's transmitter to
be "throttled back" to a low output level suitable for the transverter.
This is the way my 222 transverter is connected to my Icom IC-706 MkII.

In both cases, there are connections to the FT-847's back panel to the
interface boxes to acquire a PTT signal, so that the interface box can
perform T/R switching.  (Most transverters want a separate TX input and
RX output between themselves and the "IF" radio.)

And of course, none of the above is specific to the FT-847, it applies
to most other radios that have the appropriate control lines available.

And finally, for the brave folks willing to hack up their ~$2k baby,
there are published mods that will tap into the Tx and Rx lines inside
the FT-847 and bring them out to the back panel for this purpose.  I'm
thinking about doing this.  At the moment, this is how my 902 and 1296
transverters are interfaced to an old Icom IC-251a -- the previous
owner disabled the final amplifier and split out the Rx input line to
the back panel.  So the IC-251a is now a dedicated IF radio, and no
longer immediately suitable for normal 2 meter operation.

And, since the FT-847 wasn't designed to support transverters
directly, it doesn't have the ability to, for example, select one
of several different transverters, or directly display the net
transverted frequencies, etc.  These would be nice to have, but are
not really necessary.

Good luck!
John (KB0ZEV)
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