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Re: Topband: Receivers

To: <jt@w6cfo.net>, <topband@contesting.com>,"Earl W Cunningham" <k6se@juno.com>
Subject: Re: Topband: Receivers
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Sat, 13 Nov 2004 08:16:10 -0500
List-post: <mailto:topband@contesting.com>
> They squelched my feeling that I had a lemon when they
bench tested my
> Orion for a week with the conclusion that "there's nothing
wrong with
> it".

I actually have Earl's old radio here, so all my comments
are based on the very same radio Earl had.

I initially didn't like the radio at all. It had relay
timing problems that faulted my amplifier into standby (it
has 100% fault detection for relays and such) and some other
issues. Ten Tec corrected all of that with a firmware
upgrade as soon as they became fully aware of the problem
cause. I think it took less than two or three weeks to have
a good reliable fix. There were a few other issues that only
show up in specific situations, and TT fixed them all within
weeks of learning of the bugs.

Try to get something like that done with Yaesu or Icom!!

Right now the Orion is one of the cleanest CW transmitters
on the market. It's a far cry better than Yaesu and other
rigs, and has a cleaner SSB transmitter than the $10,000
7800. It sounds exceptionally good on SSB and AM, both
receive and transmit.

Like all radios, it isn't perfect. I dislike the menus, but
I dislike going into menus in normal operation in any radio.
I'd like some functions to be more the same as my other
radios.

The only major dislike I have is the AGC. I won't know for
sure until the AGC changes (hopefully it will someday), but
my opinion is the AGC is what causes some people to strongly
dislike the Orion. The AGC comes in quickly at a threshold
and clamps weak and strong signals to the same audio level.
IMO this is what causes weak CW signals to "blend" with the
noise. I lose the lowest layer of signals unless I have the
AGC (and RF gain) set closely for the noise power at that
moment. That adjustment is also in a menu.

Now many people have no problem doing that (case in point
Bill, W4ZV), but I have over 20 antenna combinations that I
might "pick through". Despite having my antennas normalized
to the same approximate sensitivities they are still
different arrays pointed in different directions. That means
background levels are almost always different, sometimes by
several dB. If I am trying to dig an ESP signal out of noise
I not only have to switch through and find the best antenna
combination, I have to fiddle with attenuators, RF gain, or
AGC settings to adjust background noise at or just below AGC
threshold. If I don't do that, I have the opinion Earl had.

I'd say this effect amounts to only a dB or two effective
difference in signal-to-mush, but that often is the
difference between reading and not reading an ESP signal. It
also means how our ears and mind processes weak signals has
a large effect on how we like the Orion. The bottom line is
some people are just not going to like the AGC system. I
would describe it as very "mushy" sounding when looking for
weak tones in the presence of noise, unless you get the
settings correct. Some operators will be able to find a spot
they like and love it, some are going to hate it.

It's my opinion if slope was added to the AGC to make it
more like analog AGC, people who dislike the weak signal CW
operation would have an entirely different opinion.
Sometimes engineers have a tendency to make things "too
perfect", and not consider the advantages of dynamics. I
learned this with my R4C's. When I built AGC systems with
high gain (they held the audio level perfectly flat with any
signal level change on the input) it made the receiver
"mushy" on weak CW.

This is as accurately and honestly as I can describe the
Orion. Some people are going to love it and some will hate
it. It will depend on how they "hear" signals and how
objectionable they find it to have to work the AGC as
background noise levels change. At least, unlike some other
radios, the Orion is "fixable" and TT appears to correct
things when they understand there is a problem. You can
always get your money back if you can't live with the AGC.

73 Tom


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