[JMS] 90711 VFO questions

[W1LSB - George]

Hello all!

 

After a lengthy search, I finally acquired a 90711 VFO thanks to a tip from
Bob - W9RAN, who knew that I was on the hunt for one  Since acquiring it, a
few questions have come to mind that one of you may be able to answer.  

 

I've seen that two variants of the RF output connector have been noted on
the serial number page of the JMS web site; one with a 2 pin banana jack,
and one with a UHF connector, like mine has.  The serial number of my unit
is 309, however, I found a photo of the VFO with a two pin banana jack for
the RF output; it was serial number 287.   It sounds like they may have
changed connectors somewhere between the two units.  

 

Another question is whether the high impedance plug-in adapter was standard
or optional.  The manual seems to imply that it was standard, however I
gather that not everyone has one with their VFO; I do not.  The adapter was
used to provide a high impedance output versus the standard low impedance
output.   Apparently, the plug-in adapter was made in both banana plug and
UHF connector versions as well, again per info on the JMS serial number
page.  

 

Just curious as to whether anyone know more about these differences, and
whether the high impedance plug-in adapter actually provides a benefit.
Interestingly, the VFO could be used a vintage QRP rig all by itself, given
that manual claims the RF O/P is around 1.75W 

 

Once this VFO has been restored, I'm planning to use it with a 90801 exciter
and 90831 modulator, and eventually a 90881 RF amplifier with a high level
modulator. 

 

Thanks & 73,

George - W1LSB