[TenTec] transverters on 6m

Duane Grotophorst n9dg@yahoo.com
Sat, 7 Sep 2002 08:56:49 -0700 (PDT)

--- Paul DeWitte K9OT <k9ot@mhtc.net> wrote:
> I know that there several on this reflector that use
> transverters for vhf. I
> am wondering how they would compare to  the 6n2 rig.

If you are going to be using a Jupiter as an IF radio
it would be reasonable to expect similar overall
performance to the 526 since they share a certain
amount of similarity. The main difference between the
526 and the transverter route is dynamic range
performance. The Down East Microwave and SSB
Electronic transverters have 3rd order intercept
points in the mid to high 20's (though actual
performance is ultimately dependent on the IF radio).
I believe that 526 is somewhat less than that that. If
the IF radio is an Omni V or VI you should then expect
to see its performance traits on 6M as well, as long
as the transverter in front of it is up to the task.

> Using a transverter how
> much power out will you have?

I believe that the Ten Tec 1208 will do about 8W with
3-5W of 20M drive. The Down East Microwave 50-28 will
do around 15-20 W out; I seem to be getting about 16W
out of mine. In its basic configuration it will accept
a max of 200mw of 10M drive so it requires a low level
drive signal, or the “common IF” option. There are
also transverters from SSB Electronic that will also
do about 20W out and have drive requirements similar
to the DEM units. The SSB electronic transverters do
perform somewhat better than the DEM units and are
much more polished cosmetically. The DEM 50 - 432 MHz
transverters are in plain (unpainted) die-cast Bud
boxes and are nothing special to look at. The big down
side of the SSB Electronic transverters though is that
they are very pricey.

> Are they 10w and then
> you have to use an amp
> or what?

10W will work a lot of stuff when the band is wide
open, ... and you have good feedline plus a modest
beam. Where the extra power comes into play is
extending the no propagation range of your 6M station.
If you have to choose where to put the money, put it
in the feedline and antenna first before the amp. That
way you'll hear more stuff that you can't work which
will then in turn drive you into buying the amp

> Are the filters better in an Omni V or VI
> better than most 6m rigs?

Definitely, especially if you are referring to the
common 70's and 80's vintage all mode mono-band
radios. For the 526 I would expect to have very
similar filtering characteristics to the
Pegasus/Jupiter series radios. So it should handily
outperform the all mode mono-band radios from the past
as well.

> I guess I am wondering what the advantage of using a
> transverter is.

I started out with the various mono-band and dual band
all-mode import rigs for VHF/UHF. Then I bought a DEM
transverter to get onto 222MHz with (580 Delta for the
IF). I was instantly converted to the transverter
concept; I was amazed at how the signals would just
stand out from the background noise. I’ve since gone
to a DEM transverter for 6M, again it is the way that
signals stand out from the noise that I find so
impressive. One of the key parameters to look at if
going the transverter route is its noise figure, the
Ten Tec 1208 came in at 7.3dB in the ARRL test DEM
claims 1dB or better for the 50-28, the SSB Electronic
LT6S is also 1dB. When I set up the my transverters I
set their IF output gain so they add a just
perceptable increase in RX noise when turned on (done
with a 50 ohm load on the transverter antenna

Also as a side note, the ARRL has not done any reviews
of the current DEM offerings so none of the ARRL
reviews actually reflect the performance of the newer
DEM units after mid 1997 or so. In the case of 6M what
was reviewed in Feb 1997 QST is not what is currently
shipping and is a different animal despite having the
same model number.


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