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Re: Topband: Rig Question

To: Barry N1EU <barry.n1eu@gmail.com>
Subject: Re: Topband: Rig Question
From: Guy Olinger K2AV <k2av.guy@gmail.com>
Date: Tue, 17 Jun 2014 13:45:59 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
It is interesting to see so many come down to three main players, the K3,
the Orion/RX366, the TS590S.

When I was getting ready to move off my MP, I listened to some number of
Orions before the K3's were out. I always liked what I heard. What swayed
me to K3 was W4ZV exchanging his Orion for a K3, the rather large size of
Orion (bigger than MP) vs. K3, and the K3's true diversity with identical
RX, though there was a wait for the sub RX to get in production.

Some people at the time complained about the button/menu system of the K3.
I had owned a K2 for a while, so I already had the mind set, and found
learning the K3's set easier than learning the Orion. I have used the Orion
in a Multi-X contest environment, and after I learned controls found it
quite satisfactory. However, it could not match a couple of tricks I
learned with the K3. And even now, the Orion RX366 diversity, though
considerably improved, does not quite rise to the level of the phase-locked
equal circuitry diversity system in the K3.

With continuing K3 CW use, I discovered that with the "400" and "250" eight
pole roofing filters I could do a couple very useful things for CW. I set
those up in the L3 filter configuration as 450 and 350 hz respectively and
then carefully adjusted the offsets to align skirts with the DSP skirts at
450 and 350, which maximizes the overall skirt steepness.

This created selectivity the equal of the dual Inrad filters in the MP for
"500" and "250". So far K3 is the only radio I've listened to that can dupe
the MP's super-steep skirt selectivity way down past 100 dB with dual
Inrads. That is really hard to measure down there. My fuzzy perception is
that the MP still has the K3 in this regard by just a fingernail or two.
The K3's "400" and "250" filters are electrically identical to the "500"
and "250" Inrad 8 poles used in the 8 MHz IFs in the MP. They differ only
in the housing and physical connection configuration.

For contesting, the 450 filter as one hears it is an ideal bandwidth for
running. Particularly with the steep skirts, if you don't hear up and down
with that, you are a polite distance from your adjacent neighbors. Someone,
even *very* loud up 500 Hz, just isn't there. If you get squeezed, drop
down to 350 width and use the shift a little to preserve your slot. The 350
with DSP narrowed to 200 or 150, has been able to dig out everything I've
been after in contests search and pounce. But the standard understanding of
very steep skirts is only one benefit.

The very steep skirts sharpen up key clicks to spikes. The K3's AGC with
current firmware is immune to spikes. Using NB (noise BLANKER) with "IF
OFF" and dSP t1-7, t2-7, or t3-7, the combination pretty much kills key
clicks. The effect of the three NB settings is an increasing softness to
the CW signal. Not something I like to listen to casually, but I easily
tolerate soft CW in the context of that vs loud key clicks driving down
signals with AGC, particularly given the nasty signals that can slide up
close to you in a contest. Soft CW does not seem to reduce intelligibility
any, just has all the audiophile appeal of cold mush to the palate.

The various K3 advantages listed throughout this thread are enormous
advantages in a serious contest. Outside of serious DX and contesting?
Probably overkill for a great many, and the far less expensive TS590S can
carry the freight.

I have one frequently travelling acquaintance that had owned both K3 and
TS590S and who finally settled on an Elecraft KX3 with the companion 100
watt amp which is easily remoted. There is this temptation to not consider
the KX3 a serious radio due to the size, but he says the only thing that
gets him sometimes is hearing extremely strong signals low pitched on
opposite sideband. He says his mind objects to that but it's never kept him
from copying anyone.

Should note that he uses others' K3's brought to the scene of Multi-X
contesting. Since these days it's easy to come by
just-in-case-left-in-the-car spare K3's brought by the operator mob, he
doesn't have to support the party with a major rig.

73, Guy.


On Tue, Jun 17, 2014 at 11:08 AM, Barry N1EU <barry.n1eu@gmail.com> wrote:

> I was an early adopter of the K3 and installed all the hardware audio
> updates as they were released.  I'm picky about audio and the K3 ssb rx
> audio was quite good.  At http://n1eu.com/K3/K3_notes.htm you can see
> before/after audio spectral plots showing the differences the hardware
> updates and rx equalization made.  Please ignore much of the other outdated
> info on that Web page.
>
> As others have indicated, K3 tx audio needs more careful setup (as compared
> to other radios) in terms of sufficient audio drive and compression in
> order to maintain consistent output power level.
>
> The K3 with subrx does quite a good job of pulling out the weak ones from
> the noise on topband, as does the Ten-Tec Orion/RX366.  I'd rate these two
> as top of the heap.  The new DDC/DUC SDRs are promising (Flex 6700,
> ANAN-100D) but are not quite ready for prime time in terms of diversity
> reception and full feature set, GUI, etc.
>
> 73, Barry N1EU
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