[TenTec] Auto tuner in Orion

[Carter Grabarczyk]

Gee, Steve...sorry I hit such a raw nerve and generated all that
sarcasm. As you have chosen to reply in a public forum, I will do the
same.

Steve Ellington wrote:
> 
> > I vote "no" for a built in tuner (really a "trimmer"). In addition to
> > the cost and space, two problems come to mind with internal tuners:
> >
> > 1) Limited matching range. Most internal "tuners" can match from
> > (nominally) 25 to 150 ohms, not a very great range. Remember that 150
> > ohms (3:1 SWR) gives the Yaecomwood fits and they NEED the trimmer for
> > even a relatively minor mismatch to keep from powering down, not a
> > problem with TT.
> >
> Yes it's a problem with TT. It just APPEARS to not be a problem. TT doesn't
> use ay "fold back" protection circuit on their finals. Instead, they use a
> fuse. 

Been using an Omni 6 since 1994 and have never blown a fuse, operating
CW and RTTY on all bands from 160 to 10 with various antennas.


> Instead of gradually reducing power as the mismatch increases, they
> allow a certain amount of collector current until the fuse blows. So the
> Yaecomwoods not only provide a sophisticated protection system, they also
> provide a cooling fan 

Never had any luck with fans-they either start life noisy or all of them
ultimately end up noisy. I do a lot of RTTY operating with the Omni at
100 watts, full bore output with NO external fan and still have the
original 1994 finals.


> plus a tuner to keep the finals happy. Even a triband
> beam can yield 3:1 SWRs. That "trimmer" comes in handy for this. 
> But then of
> course, FUSES are cheaper.
> 


> > 2) If you get a tuner with a wider matching range, you need larger
> > components--- which don't tend to fit inside the radio. To explain
> > further, Ohm's Law is the culprit. E=IR or E=IZ. The good news is, you
> > want a tuner with a wide matching range, say 1000 or 2000 ohms. The bad
> > news is you have Mr. Ohm causing mischief due to the high Z. For
> > example, one amp of current at 1000 ohms gives 1000 volts. This high
> > voltage is why you need large (wide spaced) components and why you hear
> > people complain that their (so-called) 300 watt tuner arcs over with
> > "only" a  100 watt transceiver.

 
> Yes if you're going to use Mr. open wire 
> fed dipole where the tuner might
> see 2000 Mr. Ohms then certainly you need a beefy tuner but the purpose of
> an internal tuner is to help the fellow who makes some attempt to provide a
> 50 ohm impedance to his rig but didn't quite make it. Antennas such as
> loops, multiband verticals, tri band beams etc. all need a little help. The
> internal tuner allows Mr. contester to band hop instantly and provide an
> exact match to his finals. They do work!
 

Not sure where all the sarcasm and bitterness is coming from here. My
"Mr. Ohm" is Georg (not George) Simon Ohm, a real person who discovered
the law that bears his name. I don't think "Mr. open wire", "Mr. Ohms"
and "Mr. Contester" are real people. I was not intending sarcasm but for
some unknown reason, you obviously are.

 
> > Keep it a real tuner and keep it separate where the radio gods intended
> > it to be...

OK, so that was a feeble attempt at humor, but the point was, it's
difficult to stick a "real" tuner in a radio without using a lot of real
estate, thus the need for keeping it separate.


> Ok...Keep the final amp seperate too. Gee, those hot transistors and high
> currents can ruin the rest of the radio. 

Never said, suggested or implied that. You did. 


> Besides, doesn't TT trust us to
> provide our own amplifiers? And those discusting low pass
> filters....shouldn't they be left out too? We could all use external tuners
> to make up for those...


Totally losing you here- I never talked about amps nor low pass filters
(disgusting or otherwise), and also not sure why "TT wouldn't trust us".


> The "radio gods" didn't intend anything. They have
> allowed free enterprise to run amok.

Again, you're losing me. I'm not sure why, how or if "free enterprise is
running amok" or what that has to do with a discussion on internal vs.
external tuners.

I am not a rabid member of the TT cult. I offer criticism (hopefully
constructive) when I feel the situation warrants (see my recent posts on
RFI susceptibility and the gold/black debate). I DO however like the
fact that TT supports radios for YEARS, and at least for the Omni VI,
the rig I am most familiar with, provided on-going software upgrades and
hardware support; e.g., the "option 1-2-3" upgrade to a "Plus"-do it
yourself at home, have the factory do it, whatever you like! As far as I
know, this is virtually unheard of in the Japanese radio industry. Also,
let me mention the time I called TT about getting my Heil Proset to work
with the Omni 6. They said an engineer would call me back within the
hour with the mod-AND THEY DID! Again, virtually unheard of with the
Japanese service centers located here. And finally (excuse my veering
towards jingoism), with the whole TV, VCR, DVD and most of the computer
manufacturers having gone to the Orient, it's sort of nice to deal with
a very accessible and generally helpful American company.

The one thing that I do like about free enterprise is that it allows
anyone bitter, sarcastic and apparently unhappy about a brand of radio
to freely be able to join the Japanese "Radio of the Month" Club.

73/Carter/K8VT