[TenTec] Orion NB vs NR

[Gregory J. Knapp]

Thanks for the explanation of the difference between NR and NB, what they
do, and how they work, it has helped me better understand their function and
use. I wish Ten Tec would put more explanation of their use in their Orion
II manual. 
My experience from using the NB and NR parallels your descriptions. In the
mornings, I receive erratic local noise 20 over 9 from somewhere near here,
but the NB takes it completely out...absolutely incredible. And the other
night on 80 meters, a signal totally undecipherable, down in the noise,
"popped" out and was readable when I turned on the NR! The Orion II is
INCREDIBLE!
73, Greg, N6GK

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of John Buck
Sent: Thursday, October 05, 2006 11:44 AM
To: Zenvrim at aol.com
Cc: Orion at contesting.com; tentec at contesting.com
Subject: Re: [TenTec] Orion NB vs NR

It seems that a lot of people confuse noise Blanking and Noise Rejection.

NOISE BLANKER (NB)
My NB is extremely effective on ignition noise and my neighbor's weed 
eating electric fence.  The S9+ fence disappears and with not much 
distortion. 

I am not sure what the difference between the so called Hardware and the 
Software options are, but sometimes one seems to work better than the 
other.  NB is effective against very short impulse type noise that can 
be somewhat irregular.  NB does not work on band noise but does 
sometimes help static crashes. 

Usually older hardware implementations have a separate wide bandwidth 
detector near the front of the receiver and if an impulse is detected, a 
switch shuts off the signal path near the front end for a short period 
of time.  In effect, it puts a hole in the signal reception to prevent 
the pulse from getting spread by the narrow band filters and detectors.  
If a system has sufficient dynamic range to not be saturated by the 
impulse then the impulse can be identified in one signal path and used 
to blank a second delayed signal that you then use for detection.  This 
approach can completely remove the short impulse from the signal you hear.

It works very well.  Sometimes my electric fence is S9+.  The NB makes 
it disappear into the S1 to 3 background.  I often have to set it at 8  
or 9.  The Orion V2.059d is better than my K2 and that is pretty good.

NOISE REJECTION
The Noise Rejection is an attempt to remove background noise and 
everything else that is not signal.  There are many different algorithms 
for this.  It works better if the bandwidth is set larger than the 
signal bandwidth so the algorithm can get a grip on the noise in order 
to remove it. 

It is not just a BW reduction approach although sometimes it sounds that 
way.  TT has tried several different schemes.  I am not sure how the 
current approach works on cw.  It works quite well on weak SSB and often 
makes an unreadable signal pop out of the noise, although it sounds a 
bit distorted.  I am not sure that it works that much better than 
adjusting the threshold and Bandwidth just right but it is a lot quicker.

NR does not work on impulse noise and other stuff that may saturate the 
filters or detectors. 

I like the idea of identifying the noise and subtracting it from the 
signal.  I think it works and will work better in the future.  I thought 
it worked better on a earlier version but it worked poorly on some of 
the interim versions.   It is better now in V2.059d but more distortion 
than I like on SSB.

Aloha,
John KH7T

The

 Max wrote:
> /Just some thoughts....could not handle the clumsiness of the 
> 1.3..however  ext T/R delay is rite on.../
> /on the 2.059d if you set the T/R at max (100) and the QSK delay at 
> 100 the transmitter will switch over and u sit there and have to wait 
> for the qsk to switch...on the 1.xxx versions they were pretty much in 
> line./
> /Q: does the Digital NB do anything???I have been operating without it 
> and there is no difference. Should it work independently of the NR?/
> /This is hard to tell but I find the hardware NB to be less effective 
> in the 2.XXX version. ( am I dreaming?)./
> // 
> /Don't do SSB. so no feed back from me./
> /73/
> /Max/

_______________________________________________
TenTec mailing list
TenTec at contesting.com
http://lists.contesting.com/mailman/listinfo/tentec

-- 
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.407 / Virus Database: 268.12.13/463 - Release Date: 10/4/2006
 

-- 
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.407 / Virus Database: 268.12.13/463 - Release Date: 10/4/2006