I bought a used C 22 some years ago and really like it. Being direct
conversion, it does not have single-signal reception, so you hear a
signal on both sides of zero beat. If you hear QRM, just offset the RIT
to the other side of zero beat. However, it's not going to be good for
contesting on a crowded band. I use it mainly for traffic handling on
80 meters
On the other hand, the PTO is very stable and the receiver is very quiet
and with no filter ringing. CW sounds really nice on it and the audio
filter is quite good. Unlike the ARGO, the C 22 has an RF gain control.
One interesting thing: I am plagued with neighbor noise on occasion.
It is broadband modulated white noise with an S9+ buzz every 30 kHz. it
is probably a plasma TV or switching power supply or battery charger.
Amazingly, the audio filter in the C22 takes out most of this noise but
the crystal filters and noise blankers in my Corsair and Paragon do not.
A word of caution: Early models had problems with blowing finals and
drivers until Ten Tec replaced them with 2SC1969s, which are still
available fro RF Parts Co. Even with the better final, there is no high
SWR protection and unless you have a 5 A fast circuit breaker or the
matching Ten Tec power supply ( properly adjusted), a few dits into a
mistuned or wrong antenna with blow the finals.
73,
Bob WB2VUF
On 12/30/2017 3:14 PM, Dukes HiFi wrote:
I myself could have been a bit more tactful as well.
However, direct conversion has so many adverse artifacts that it makes me cringe to think of
using it. The C21 is quite a lot better, IMHO than is a true “direct
conversion” design.
The new SDR direct conversion process is a different matter with different issues,
some good, some not good. But at least they don’t suffer from arbitrary
sideband, hum and adjacent frequency overload (unless you send the A to D into
overflow).
73
Gary
On Dec 30, 2017, at 1:24 PM, Lee <lee@wa3fiy.com> wrote:
Yes, both Century 21 and 22 hear both sidebands all the time.....just LIKE a
simple direct conversion receiver. Granted, the conversion details of both
radios differ from a simple direct conversion receiver.
I may have started this discussion when I said "...It tunes just like a direct conversion
receiver where you hear both sidebands as you tune thru the signal...." in response to the
original question. Emphasis maybe should have been put on the words "TUNES JUST LIKE".
Sorry, I should have been more clear I guess. :-)
HNY everyone,
73,
-Lee-
WA3FIY
------ Original Message ------
From: "w0ep" <w0ep@w0ep.us>
To: tentec@contesting.com
Sent: 12/30/2017 1:56:17 PM
Subject: Re: [TenTec] C22
I must be misunderstanding..
My C21 hears both sidebands all the time.
On 12/29/2017 10:47 PM, Dukes HiFi wrote:
Its advantage over direct conversion is freedom from hum and images (wrong
sideband).
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