[amsat-bb] Re: AO-51 V/S

Auke de Jong, VE6PWN sparkycivic at shaw.ca
Tue Apr 20 12:34:28 PDT 2010

In my sub-urban QTH, I can hear nothing EXCEPT wifi noise starting right at 
2401.025MHz in all directions.  I'm planning to optimise my BBQ grill/3733 
antenna in order to improve off-axis rejection, and hopefully the noise - 
without having too sharp of pattern for manual tracking of AO-51.  I'm also 
contemplating ditching the BBQ grill reflector in favor or a small dish to 
get better f/b and cut the noise.  It makes me wish that satellites would 
stick closer to 2400MHz such as AO-40- it's less noisy there.


----- Original Message ----- 
From: "Luc Leblanc" <lucleblanc6 at videotron.ca>
To: <amsat-bb at amsat.org>
Cc: <eu-amsat at yahoogroups.com>
Sent: Tuesday, April 20, 2010 7:14 AM
Subject: [amsat-bb] Re: AO-51 V/S

On 20 Apr 2010 at 2:24, Bob- W7LRD wrote:

Date sent:      Tue, 20 Apr 2010 02:24:55 +0000 (UTC)
From:           Bob- W7LRD <w7lrd at comcast.net>
Subject:        [amsat-bb]  AO-51 V/S
To:             amsat-bb at amsat.org

> This last pass worked W6YX and heard Kerry, WC7V. Noticed some very deep 
> fades.
> 73 Bob W7LRD

Did anyone ever tested their downconverter who is basically a receiver to 
measure the amouint of desense the WI-FI , spread spectrum and
frequency hopper device and so on produce on 2.4Ghz?

Desense is very noticeable on VHF and UHF when a transmitter is transmitting 
near a receiver as per i can see on a PCR-1000 scope screen
there is always a 10db noise floor but i'm not sure if this level is not 
really much higher as the scope seems to not be fast enough to
display the real peak level of all the signal on 2.4Ghz.

If a fairly high amount of desense is always present this could explain why 
the downconverter is lacking sensitivity and why some normal
fades appears deeper than they really are. And what is worse is the WI-FI 
QRM is also right on the received 2.4Ghz amateur band.

Here i have to switch off my WI-FI router and my 2.4Ghz camera when i want 
to listen on 2.4Ghz and the camera is the worse as she give 30
over 9 very wide  spread signal.

Opinions are welcome.


Luc Leblanc VE2DWE
Skype VE2DWE

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