Re: Question about KNB2 Noise Blanker (Gain reduction in NB2 posit...

[G3VVT]

Hi Ken,
 
This effect of gain reduction when NB2 is selected does not happen on  my K2.
 
A question is are you receiving large doses of noise that the  blanker is
removing as the operation of a noise blankers is to cut out the  affected section?
If the noise is severe enough this can result in distortion and  reduction of
signal.
 
You can check this by disconnecting the antenna and observing a signal from  
an RF generator under the same test.
 
Took quite a time before I could even say my NB was even working. Only  works
with the right kind of noise such as ignition interference. Shades of  
British Rail and their problems with the wrong kind of leaves on the railway  lines!
 
Regards,
Bob, G3VVT
K2 #4168
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Stewart Baker]

On Thu, 30 Dec 2004 05:46:52 EST, [hidden email] wrote:

> Hi Ken,
>
> This effect of gain reduction when NB2 is selected does not happen on  my K2.
>
> A question is are you receiving large doses of noise that the  blanker is
> removing as the operation of a noise blankers is to cut out the  affected
> section?
> If the noise is severe enough this can result in distortion and  reduction of
> signal.
>
> You can check this by disconnecting the antenna and observing a signal from
> an RF generator under the same test.
>
> Took quite a time before I could even say my NB was even working. Only  works
> with the right kind of noise such as ignition interference. Shades of
> British Rail and their problems with the wrong kind of leaves on the railway
> lines!
>
> Regards,
> Bob, G3VVT
> K2 #4168
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

Hi Ken,

No loss of signal when switching in my NB, but it is very selective
on what type of noise it blanks.

73
Stewart G3RXQ

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Ken G3WCS]

[hidden email] wrote:
>
> Hi Ken,
>  
> This effect of gain reduction when NB2 is selected does not happen on my K2.

Hi Chaps.


Thanks to all for the replies.

I have fixed the problem now. It was the 2N7000 FET (Q6) on the KNB2
board. I used an anti-static wrist strap and mat during construction so
thought ESD protection was OK. Maybe faulty from the start. Maybe me.
Who knows?

Anyway, working correctly on both NB1 and NB2 now with no reduction of
gain. Just need to find another 2N7000 for my XV60 board.

Thanks again and Happy New Year.

Ken.

--

Ken G3WCS <[hidden email]>
IO83rh : Cheshire : NW England
(+44) (0)870 765 1632 (home)
(+44) (0)7733 400 950 (mobile & sms)
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Mike Morrow-3]

Stewart wrote:

>No loss of signal when switching in my NB, but it is very selective
>on what type of noise it blanks.

The very simple noise blankers of the K1 and K2 seem to help only on ignition, motor commutator, and other such similar noise.  These blankers seem completely ineffective on all of the various types of power line noise I've encountered, unlike the more sophisticated blankers in most other rigs produced in the past 25 years.   The blankers in my ancient 22-year-old TS-430 and 11-year-old TS-50 work wonders in comparison.

Maybe it's time for a re-design of the Elecraft blanker system.

73,
Mike / KK5F


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[AC6JA]

I've had the opposite luck.  My K2 takes out local electrical noise  and
ignition noise where my TS-570S and IC-746 noise blankers didn't do a  thing.  
I've been very happy with the noise blanker in my K2 and think  that's been the
best option for the buck!
 
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[N2TK]

Are there different versions of the KNB2? I haven't been impressed with mine
compared to my 950.
N2TK, Tony



-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of [hidden email]
Sent: Thursday, December 30, 2004 11:52 AM
To: [hidden email]
Subject: Re: [Elecraft] Question about KNB2 Noise Blanker (Gain reduction
inNB2 posit...

I've had the opposite luck.  My K2 takes out local electrical noise  and
ignition noise where my TS-570S and IC-746 noise blankers didn't do a
thing.
I've been very happy with the noise blanker in my K2 and think  that's been
the
best option for the buck!

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Douglas Westover]

I find the KNB2 in my K2 to be very effective on the usual type
of powerline noise I encounter. However there is a variant,
which sounds the same to the ear, that the blanker won't
touch. I don't have a 'scope so can't look at what the
difference in waveform might be, but in general I am
quite pleased with the blanker. That, plus the NR mode
of the KDSP2 provides really good noise reduction.

Doug
W6JD
K2/100 #1626

----- Original Message -----
From: <[hidden email]>
To: <[hidden email]>
Sent: Thursday, December 30, 2004 8:52 AM
Subject: Re: [Elecraft] Question about KNB2 Noise Blanker (Gain reduction
inNB2 posit...


> I've had the opposite luck.  My K2 takes out local electrical noise  and
> ignition noise where my TS-570S and IC-746 noise blankers didn't do a
thing.
> I've been very happy with the noise blanker in my K2 and think  that's
been the

> best option for the buck!
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Bryce A. Carr]

Amen! The K2 NB is particularly poor when using low level rx only ants as
noise pulses are heard in audio, but are not adequate strength to trigger
the blanking mv.
  Aloha,
            Bryce, kh6at
----- Original Message -----
From: "Mike Morrow" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, December 30, 2004 6:43 AM
Subject: Re: [Elecraft] Question about KNB2 Noise Blanker (Gain reduction
inNB2 posit...


> Stewart wrote:
>
> >No loss of signal when switching in my NB, but it is very selective
> >on what type of noise it blanks.
>
> The very simple noise blankers of the K1 and K2 seem to help only on
ignition, motor commutator, and other such similar noise.  These blankers
seem completely ineffective on all of the various types of power line noise
I've encountered, unlike the more sophisticated blankers in most other rigs
produced in the past 25 years.   The blankers in my ancient 22-year-old
TS-430 and 11-year-old TS-50 work wonders in comparison.

>
> Maybe it's time for a re-design of the Elecraft blanker system.
>
> 73,
> Mike / KK5F
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-3]

Bryce,

Certainly, when the noise pulse is not strong enough to reach the gating
threshold, no blanking will occur.
The solution is to add a preamplifier.  In some cases it will be sufficient
to just turn on the preamplifier in the K2, it does depend on the Rx antenna
output level.

Any gated noise blanker will have similar behavior, it is not unique to the
K2 implementation.

73,
Don W3FPR

----- Original Message -----

> Amen! The K2 NB is particularly poor when using low level rx only ants as
> noise pulses are heard in audio, but are not adequate strength to trigger
> the blanking mv.
>  Aloha,
>            Bryce, kh6at


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Bryce A. Carr]

Hi Don,
I agree, but as Mike, KK5F,  pointed out, and I also noticed with my old
TS-830S and TS-140S, when using the same receive only phased loops both of
those rigs work fine at that low level and the K2, even with K2 preamp on,
doesn't.
 It would be a better idea to put more gain in series with the NB pulse amp
and put a nb level control on it so it will work as well as the antique
gear.
I have dxcc on 160m from a city lot and noise blankers are a big thing in my
life. Hi.
          Aloha,
               .Bryce, kh6at
----- Original Message -----
From: "W3FPR - Don Wilhelm" <[hidden email]>
To: "Bryce A. Carr" <[hidden email]>; "Mike Morrow" <[hidden email]>;
<[hidden email]>
Sent: Friday, December 31, 2004 1:14 AM
Subject: Re: [Elecraft] Question about KNB2 Noise Blanker (Gain
reductioninNB2 posit...


> Bryce,
>
> Certainly, when the noise pulse is not strong enough to reach the gating
> threshold, no blanking will occur.
> The solution is to add a preamplifier.  In some cases it will be
sufficient
> to just turn on the preamplifier in the K2, it does depend on the Rx
antenna
> output level.
>
> Any gated noise blanker will have similar behavior, it is not unique to
the
> K2 implementation.
>
> 73,
> Don W3FPR
>
> ----- Original Message -----
>
> > Amen! The K2 NB is particularly poor when using low level rx only ants
as
> > noise pulses are heard in audio, but are not adequate strength to
trigger
> > the blanking mv.
> >  Aloha,
> >            Bryce, kh6at
>
>
>


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com