[TenTec] Advice on my Omni VI

[Jim Brown]

On 4/13/2013 12:35 AM, Rick - DJ0IP / NJ0IP wrote:
>
> When I read all of the bitching here about bandscopes, I get the 
> impression many people believe "if you can't 'SEE' them, you can't 
> work them."  They value that even more than a manufacturer's support 
> for older kit.
>

I find the P3 VERY useful.  It's great for finding a frequency when you 
want to run and to recognize and chase down electronically generated 
noise, and well enough calibrated to document the excessive bandwidth of 
lousy (or badly adjusted) rigs and amps.

> Jim, I'm anxious to see the KX3's matching amp.
>
> I really love the looks and features of Ten-Tec's Model 418.
>
> I think that would make a great combination.
>
> BTW, did you say you have a KPA-500.
>

Yes, and i use it a lot when I don't need the extra 4dB of the Titans.

> How smooth does it run QSK?
>

VERY smoothly.

> It doesn't seem to use a keying loop.
>

As I understand it, FCC rules REQUIRE that a "keying line" be used to 
put it in TX mode. It operates with "make to ground" to TX.

> ·What is the T/R method?  Pin-Diodes, vacuum relay, ?
>

Pin Diodes.

> ·At what SWR level does it switch to FAULT?
>

I don't know the detail, but from watching it operate, it seems to be on 
the basis of excessive reflected power or excessive current. There are 
(at least) two levels of protection. First, a stepped attenuator is 
switched into the input to back off drive a dB or two at a time, and it 
will be switched back out if you reduce drive or fix the event that 
caused it to operate. All of that is seamless, and you don't fall out of 
TX.  A much more severe mismatch will drop it into standby, and requires 
a manual reset of the "standby/operate button.

> Amps switching to fault are a huge problem in contesting.
>
> I had only one, used it for two years, then dumped it for that single 
> reason.
>
> Seems every time I looked at it, the red fault light was on, due to 
> the long dipole blowing in the snowy wind.
>

My amps are all on the operating desk alongside the rigs, with power 
supplies for the Titans under the desk.  Logging computer in the center, 
then the rigs either side, then the amps. The Titans, of course, need to 
be tuned.  The KPA does automatic bandswitching (it samples RF, and 
needs only a dit or a tap of the mic).

Except for my 80/40 dipoles, all of my antennas are well matched, but 
the SteppIR is manually tuned, because I switch it between the two 
rigs.  I've recently replaced my 229s and 238s with the new Elecraft 
tuner, which is good for legal limit power with SWR under about 3:1.  
Very nice.  I was a beta tester.  It also auto-switches. Integrates 
perfectly with the KPA, but it's tricky to use with the Titans because 
of how their logic prevents hot-switching. I'm using them successfully 
with the Titans, but you've got to keep your wits about you. :)

BTW -- the Titans are VERY tolerant of moderate faults -- as long as you 
don't draw excessive grid current long enough to wipe the tubes.  I once 
operated through a big storm that was causing my 160M vertical to 
intermittently short at the radial plate. When I saw it happening, I'd 
interrupt the CQ, then start all over again. The tubes are still in the 
amp five years later. :)

73, Jim K9YC