[TenTec] Corsair II noise blanker

Mon Mar 31 22:18:25 EDT 2014

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 at verizon.net>
To: "Discussion of Ten-Tec Equipment" <tentec at 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 at DJ0IP.de>
>> To: "'Discussion of Ten-Tec Equipment'" <tentec at 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 at 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 at DJ0IP.de>
>>> To: "'Discussion of Ten-Tec Equipment'" <tentec at 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 at 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 at 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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>>
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>
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