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Re: AM Band during eclipse
To: CRTech <crtech@crtech.org>
Subject: Re: AM Band during eclipse
From: Willie Barnett <wbradiolists@gmail.com>
Date: Mon, 21 Aug 2017 10:27:16 -0400
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Suggestion: Narrow the bandwidth to just the actual AM allocation, 530 to 1710. While that's not much, it will at least knock a few percent off the size of those files. :)

I'm not sure what other steps could be done to reduce the size of the files, as I have never actually experimented with anything like that, directly. My ONLY experience with SDR has been via those kind souls that have hooked theirs up to the Internet, allowing others to "poke around" in them. :) It's truly fascinating to see a whole swath of spectrum, and just click on a trace to listen! :)

Try tweaking the sample rate, bit depth, etc. while comparing the results to find the best compromise between getting usable signals vs reasonable file size.

Notching-out a strong local signal is fairly easy with a tuned resonant circuit in the right place. :) YEARS ago, now, I used a car radio (well shielded) to monitor a local AM station for EAS compliance. Trouble was, we were at 1500Khz, and that station was on 600! Yep, nice STRONG heterodyne from the image of our signal! A simple series resonant ckt across the antenna terminals, carefully tuned to 1500, fixed it right up! :)

If you're using a loop antenna, try placing a cheap transistor radio near (or within, you'll have to try it) and tune the radio carefully until you see the 650 signal notch out. You don't even need a battery in the radio! Just resonating the internal loopstick antenna in close proximity (and properly oriented) to your receiver loop, should give you a 20+ dB notch.

Willie...


On Fri, Aug 18, 2017 at 8:05 PM, Kevin Kidd <kkbroadcastengineering@gmail.com> wrote:

Willie,

I am unsure how to best present the wide band IQ files as they will be enormous.  It looks like about 26gb per hour for 400khz thru 1800khz IQ recording.  I may try to break them into 15min segments or something but still mighty big files.

A YouTube video may be best if I hear something interesting in post processing.

I think it will be pretty darned interesting in a radio geek kinda way...

My NRSC shielded loop that will be in the totality is fairly deaf but the receiver at my shop (70 miles SW of totality) is connected to a OCF 80m "dipole" at 80ft and hears the regions MW pretty well. 

Now if I can just get that pesky 650khz station in Nashville to go off for a couple of hours...

Regards,
Follow-Ups: Re: AM Band during eclipse
(Kevin Kidd <kkbroadcastengineering@gmail.com>, 22 Aug 2017 17:27:19 -0000)
References: AM Band during eclipse
(Willie Barnett <wbradiolists@gmail.com>, 18 Aug 2017 16:46:40 -0000)
Re: AM Band during eclipse
(Kevin Kidd <kkbroadcastengineering@gmail.com>, 19 Aug 2017 00:05:34 -0000)
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