[RFI] RFI / Band Monitor

[Jim Smith]

One could use the 24/7 NCDXF beacons.  BeaconSee does a very nice job of 
displaying the beacon signals on the computer screen and will 
automatically write the image to a file at intervals you specify.  If 
you display the beacons on all 5 bands from 20 to 10, it takes 2 hours 
to fill the display with, I think, 8 measurements at 15 minute intervals 
for each beacon on each band.  The result is qualitative, rather than 
quantitative, no numbers, but high noise levels show up quite dramatically.

This doesn't help, of course, for bands below 20m.  It does have the 
advantage of being really cheap and easy to implement, provided your rig 
can be interfaced to a computer.  How cheap?  Free if you don't want to 
automatically file the images.  Paying a registration fee ($30?) allows 
auto save.  http:\\www.ip.pt/coaa

Given that you'll be receiving from beacons all over the world on many 
bands, an all-band vertical is probably the best antenna to use.  I use 
a CC R-5.  Works great.

The usual disclaimer applies.

73 de Jim Smith   VE7FO

Jim wrote:

>Martin, 
>
>It would seem to me that some 'standard' QSO
>contacts need to be run (scheduled) and the 
>S/N ratio measured and 'recorded', maybe on a 
>daily or weekly basis, demonstrating a negative
>slope, to fit in with Ed's comment and philosoply 
>I think. 
>
>'Harmful Interference' could then be seen numerically
>how it impacts actual QSOs via 'degraded S/N ratios'. 
>By contrasting 'normal' signal levels and 'noise' signal 
>levels in the bands as opposed to absolute signal 
>strengths of 'noise' alone the 'harmful'  aspect could 
>be emphasized (however, absolute signal levels 
>are/would always be useful for engineering purposes).
>
>Using a slightly different methology, perhaps some 
>statistics of 'average' received signal strengths from 
>various stations on various bands could be 'established'
>as 'figures' for comparison against measured, 'absolute' 
>noise levels later on, and from which a determination, 
>after examination of the recorded data, one could deem 
>that certain noise 'levels' are indeed deemed to be
>'harmful'.
>
>One could record the activity on a couple of the more
>popular HF nets, including the county hunters net, and
>this collected data could be used as a baseline figure 
>as the resident, normal, expected in-band amateur 
>activity against which 'absolute' noise figures could be 
>compared. And the 'noise' need not be active at the 
>same time as the nets are; the two can be compared
>at any convenient time, one against the other.
>
>Just my two cents this evening ...
>
>Jim  de WB5WPA
>
>
>
>----- Original Message ----- 
>From: "Martin Ewing" <martin at aa6e.net>
>To: <rfi at contesting.com>
>Sent: Friday, November 05, 2004 2:44 PM
>Subject: [RFI] RFI / Band Monitor
>
>
>  
>
>>Folks,
>>
>>I have been working on a semi-realtime band monitor
>>system, and there are some early results at
>>www.aa6e.net/aa6e/rfi/monitor.html.  I am recording
>>what happens on 40 & 20 M in 2 kHz channels in my
>>particular environment.
>>
>>Why would we want to do this?
>>
>>-Learn a little about propagation conditions vs solar
>>activity, etc.
>>-Pick up (and record) RFI problems
>>-Get a baseline, pre-BPL deployment
>>-Too much hardware, software, and time available ;-)
>>
>>Ed Hare actually suggests it's a bad idea to make
>>baseline recordings if you want to proceed against the
>>power companies with a BPL complaint.  The logic is 
>>perverse, but he may be right.  See Ed's famous URL:
>>http://www.arrl.org/~ehare/bpl/measurements.html .
>>
>>But as a frustrated radio astronomer and programmer, I
>>couldn't resist.  Already, I see some interesting
>>"UFOs", but they're probably somewhere in my house.
>>
>>The process needs to be automated more, and I will
>>have to decide if it's worth trying to make a
>>long-term record (months/years).  
>>
>>How could this stuff be made more useful?
>>
>>73, Martin, AA6E
>>
>>    
>>
>
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