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Re: [TenTec] notch filter for Eagle?

To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Subject: Re: [TenTec] notch filter for Eagle?
From: "rick@dj0ip.de" <Rick@DJ0IP.de>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 20 Jul 2017 17:05:30 +0200
List-post: <mailto:tentec@contesting.com>
Gary, you are covering your "assets", aren't you.
Once you say "to me", END of discussion - hi.

The notch filter outside of the AGC loop can be very affective as long as the 
disturbing carrier is weaker than the wanted signal.  That happens as often as 
not, but  Murphy tries to prevent that when you are trying to work that rare 
one.

Once the disturbance is stronger that the desired signal, game over.

I would not say Icom is the leader;  I would say it's the winner.
It found the winning combination of good enough new technology, while listening 
to what the majority of the users want (i.e. KNOBS).  FLEX's stubbornness in 
that respect will possibly lead to the downfall of the company.

Currently I would say ANAN is the technology leader but as you say, who wants a 
radio without knobs.  That's like having a good bottle of wine but no cork 
screw!

I'm no expert on SDR technology but they achieve the notch through a 
combination of phasing and time slices.  All I can say is that it certainly 
works!

For me the little SKY-SDR is finally a replacement for my Argonaut 509 radio.

73
Rick, 


-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Dukes HiFi
Sent: Thursday, July 20, 2017 4:21 PM
To: Discussion of Ten-Tec Equipment
Cc: Greg S
Subject: Re: [TenTec] notch filter for Eagle?

Rick:

Since your SDR has notch inside the AGC loop, it must not be all that difficult 
to accomplish. Of course, I do not have sufficient knowledge of SDR designs to 
know how they manage AGC or notch functions.

Too bad no one is writing software for the Orion anymore. It would be nice if 
that change could be done. I might even buy one then...

I should have added the caveat in my remark regarding the relative uselessness 
of a notch filter outside the AGC line by saying “useless to ME”. Others are 
certainly free to believe that an external notch filter (that is, external to 
the AGC loop)  is equally effective (manual or otherwise).

This topic was beaten to death maybe 30 to 40 years or so ago when relatively 
decent external filters, such as the Autek and later on when DSP devices were 
introduced. They were pitched as offering Collins or Drake-like performance in 
otherwise mediocre receivers. They didn’t, but they did make operation less 
annoying to some degree. They also worked pretty well if you turned off the AGC 
and used the RF gain pot to compensate for variations in signal strength.

Gary

PS: Icom is the leader here in direct SDR, FOR ME. The performance is not there 
yet but I have zero interest in needing to have my PC on to run my radio. The 
7300 does not need a PC to work, the others do. They are headed in the right 
direction. If Ten Sec ever introduces a new radio, likely it will head in that 
direction too.

> On Jul 20, 2017, at 7:08 AM, rick@dj0ip.de <Rick@DJ0IP.de> wrote:
> 
> notch

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