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[TenTec] K2 rcvr versus Omni VI rcvr... can anyone else duplicate my res

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Subject: [TenTec] K2 rcvr versus Omni VI rcvr... can anyone else duplicate my results?
From: johnclif@ix.netcom.com (John Clifford)
Date: Mon, 27 Aug 2001 00:10:19 -0700

I have just purchased a Ten-Tec Omni VI/Option 1 from another ham... I
bought it because I got a fantastic price for this rig (less than half of
what a new VI+ goes for, shipping and a 705 mic were included) and I have
always wanted one.  I've been using it last week while waiting for my PA
transistor repair kit to arrive from Elecraft, and have generally been
pretty happy.  It fixes the major shortfall of my KPA2-less K2... I've been
able to work pretty much every signal I can hear even with my crummy
cloudwarmer antenna, and I've put a bunch of new DX countries in the log.

Once I finished ripping out and replacing the bad parts on my K2, I set it
back up on the bench for a little informal "A/B" testing using the waterfall
spectrum analyzer in WinPSKse.  I figured that tuning both radios to the
same frequency and then examining identical signals through the identical
antenna and path would be enlightening.  Given that the background was
adjusted to the same intensity (via the volume controls on each rig), the
difference in signal strength, as well as the ability to handle weak signals
in the presence of strong signals, should be immediately observable.

To make a long story short... the K2 seems to as sensitive, with a little
better ability to handle strong adjacent signals (selectivity).  Perhaps the
K2 is a teeny tiny bit more sensitive, as it seems to be able to pull a
faint PSK31 trace out of the background a hair better.  The S-meters seem to
compare favorably with the same readings on both for identical signals.
Note that with the pre-amp in on the K2, it really grabs weak signals out of
the noise better than the VI.  (If there is a pre-amp on the VI I can't find
it, and I have the RF control turned all the way up.)

Now... I still have to align the K2 on transmit(getting ready to do it, but
just thought I'd try this for grins and didn't think I'd get the results I
am), and I don't know the status of alignment on the Ten-Tec (and I'm sure
it needs an alignment since it's 7 years old and has been subjected to the
tender mercies of United Parcel Stompers), so this observation is worth what
it is worth.  I am going to align both rigs carefully this week, and then
try the same test again.

If anyone else out there has both the K2 and Omni VI or VI+ (the VI/Opt1 is
a VI upgraded to a VI+ without the VI+'s 9Mhz IF/mixer board and its extra
9Mhz filter slot), please try this and post what results YOU get.  I
expected there to be some difference, but very little... and quite frankly I
expected the difference to FAVOR the Omni VI just slightly.

What this tells me is that the only difference between the K2 and the Omni
VI+ is the additional features like passband tuning, the notch filter, and
DSP.  I'm not yet experienced enough as an operator to fully understand how
to get the most out of these features.  The notch filter is a pretty neat
gizmo and makes dropping out a loud signal easy... I wish the K2 had one.  I
dunno how the KAF2 will compare to DSP filtering (the Omni VI's DSP works
VERY well, IMO, far better than the MFJ-784B and FAR better than I thought
it would), but it would be interesting to compare a perfectly-aligned Omni
VI+ to a loaded K2 (I don't have the test gear to do any such comparison

As an aside, I opened up the VI when I received it (heard something rattling
around inside) and re-installed the plastic cover for the crystal oven.  Of
course, being a proud home-builder I had to check out the quality of
construction.  The two things I noticed right off the bat were 1) there's a
heck of a lot of wiring in the Omni VI that you don't see in the K2, and 2)
the K2's PC boards look a lot nicer (probably because Elecraft knows that
manufacturing will be done by the purchaser, and clearly-marked PC boards
are a must).  One thing they both share... no SMD parts (I believe newer
Ten-Tec rigs use SMDs)!  And Ten-Tec, like Elecraft, encourages owners to
mess with 'em (to a point).

On a related note, how many K2'ers out there have heard of N4PY's "ultimate"
setup which consists of a Ten-Tec RX340 receiver and a Pegasus transceiver,
along with custom software that turns both radios into a dual-receiver rig
with the RX340 being the primary VFO and the Pegasus being the sub-VFO and
transmitter.  These radios were chosen for the receive performance of the
RX340 (at $4200 a pop) and the fact that both radios can be completely
(volume, RIT/XIT, filters, etc) via software.  Seems to me the same thing
could be done with a pair of K2s (control the volume via the sound card),
and with two 100w amps you really would have the ultimate station... if the
K2's receiver compares to the RX340 as favorably as it SEEMS to the VI+.

 - jgc

John Clifford KD7KGX

Heathkit HW-9 WARC/HFT-9/HM-9
Elecraft K2 #1678 /KSB2/KIO2/KBT2/KAT2/KNB2
                  ...waiting for KPA2 & KAF2!
Ten-Tec Omni VI/Opt1

(listed in order of acquisition, not performance!)

email: kd7kgx@arrl.net

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