Some of the older radios used a circuit best described as a noise limiter.
In effect it was a diode clipping system and yes it did add a good bit of
distortion to the signal.
I find that with today's radios being much quieter electronically, one
should use a lot less RF Gain than imagined. I recall Rob Sherwood
describing the correct value of RF gain as being that value that allows the
AF output to rise 3 dB or 6 dB from no antenna connected to having the
antenna connected. Once this level is obtained, I was amazed at how low the
noise appeared as compared to signals on the band.
73
Bob, K4TAX
----- Original Message -----
From: "Bwana Bob" <wb2vuf@verizon.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Monday, March 31, 2014 9:08 PM
Subject: Re: [TenTec] Corsair II noise blanker
I've noticed that, too. The simple audio filter in my Century 22 does an
amazing job of filtering out noise (mainly a buzz from switching power
supplies and plasma TVs in the neighborhood). Also, it does not introduce
distortion like the blanker in My Paragon.
I wonder if just keeping the RF gain low so the noise doesn't capture the
AGC and using an outboard SCAF audio filter would be effective against
impulse noise.
73,
Bob WB2VUF
On 3/29/2014 11:37 PM, paulpolace wrote:
Rick,
Actually was only a variable 8 pole "audio" bandpass filter, but somehow
produces some fantastic results in relation to noise as well.
There was always talk that the C-22 incorporated the "Jones Filter" but
the patent on it was filed in 1989 and the C-22 made in early mid 80's 84
ETC.
The early Argonauts were produced prior to the Century-22 so not sure if
the C-22 inherited any circuitry from them?
If you ever come across one Rick, you must give it a spin, kind of hard
to explain the experience!
Yes I remember the outboard filters, in the day manufactured for the
Woodpecker...Now we have neighbors electric fences and grow lamps to deal
with!
Kind Regards... -GL- -DX-
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
----- Original Message ----- From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Saturday, March 29, 2014 7:21 PM
Subject: Re: [TenTec] Corsair II noise blanker
Are you referring to the LC BPF's in the front end?
I never saw a Century but if it has the elevator like the Argonauts and
Tritons had in those days, then yes, in general it did help reduce
overall
noise, but it will not help on things like the pop of an electric fence.
In fact, back in the days of the Woodpecker, whose signal was wide but
its
signal strength was frequency dependent, I could slightly de-tune the
preselector on my Omni and then hear signals better than I could on JA
rigs
with no tunable preselector... as long as I wasn't trying to listen to a
signal near the Woodpecker's frequency.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of
paulpolace
Sent: Saturday, March 29, 2014 11:35 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Corsair II noise blanker
Correct Rick!
The topic is NB... NOT... NR.
Hard to believe or understand... yet my Century-22 actually handles
noise
better than the Omni VII, and were going way back.
Could the variable 8-pole bandpass filter been designed so well that it
accounted for such noise as well? or possibly just my experiences.
The Eagle here also does a better job than the Omni VII.
Interesting the NB in My Kenwood TS-590 works unbelievably well, yet the
design on that one allows a variable user interface to set accordingly.
Also Good Info there N6KB
-73- -DX-
+++++++++++++++++++++++++++++++++++++++++++++++++++
----- Original Message -----
From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Saturday, March 29, 2014 3:02 PM
Subject: Re: [TenTec] Corsair II noise blanker
Correct, but the topic was NB, not NR.
The Eagle's NB is better than the OM7's.
The reverse is true for NR.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of R.
Eric
Sluder - W9WLW
Sent: Saturday, March 29, 2014 5:16 PM
To: Discussion of Ten-Tec Equipment; K8JHR
Subject: Re: [TenTec] Corsair II noise blanker
I like the NR in the Omni VII much better than the one in the Eagle.
The
audio characteristics in the Eagle change dramatically in SSB and AM
modes.
On March 29, 2014 12:22:06 AM EDT, K8JHR <jrichards@k8jhr.com> wrote:
|Ken and Bob -
|
|Man... thanks - exactly the sort of explanation I wish they would put
|in user manuals for guys like me who are not radio engineers.
|
|Sidebar --
|
|There is an on-going debate on a Brand X radio forum, whether one NB
|(and/or NR) circuit is better than another. The answer seems to be:
|"it depends" on the type of noise, and how it interacts with the
|desired signal.
|
|My Take --
|
|Satisfaction with NR and NB is entirely dependent on one's
|expectations, generally, and one's tolerance of the necessary tradeoff
|between
|intelligibility and audio quality. I am a fan of both internal and
|outboard DSP noise filters, but I know greater intelligibility comes
|with a price in lower audio quality.
|
|On the Brand X forum, some operators expect clean, pure, audiophile
|results after scrubbing and scouring with NR, NB, and related tools.
|Unfortunately, there just ain't no free lunches these days.
|
|Wish List Item --
|
|I like the NR on my Omni VII, although I preferred how it worked in
|earlier firmware. (I am less enamored with the NR on my Orion II.)
|
|Too bad we cannot select feature updates from a smorgasbord of
firmware
|
|versions, sort of a mix-n-match thing. Now, THAT would be cool. (I
|can, however, just imagine the programming nightmare THAT might
entail!
|
| We would be visiting John Henry in the looney bin sooner than later!)
| ;-)
|
|Just My take.
|
|------------------------ K8JHR ------------------
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