[RFI] RFI / Band Monitor

[Jim]

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
>