Re: [IRCA] PL-606 odd behavior in Lakeside, CA recently

[Stephen Airy <pianoplayer88key@xxxxxxxxx>]

Responses inserted below...



________________________________
 From: Mark Durenberger <Mark4@xxxxxxxxxxxxxxx>
To: Mailing list for the International Radio Club of America <irca@xxxxxxxxxxxxxxxx> 
Sent: Wednesday, December 7, 2011 7:21 AM
Subject: Re: [IRCA] PL-606 odd behavior in Lakeside, CA recently
 
>>  Stephen, my two cents worth on a couple of things I noticed from your first video:

>>  ++ If your goal was KSL:

>>  1.  You probably could have favored KSL against KCBQ by dialing to 1158 or so...still within the KSL bandwidth but farther away from the 1170 sidebands.  I'm sure you've done that.

If I had done that, I would have been slightly outside KSL's bandwidth, distorting its audio somewhat.  I had the radio on its "1 kHz" bandwidth setting, which is really translated to +/- 1 kHz / audio frequency response (it actually is probably more like 1.5 or 1.8), which to traditional bandwidth police should probably read "2 khz" as they count the entire bandwidth, not the bandwidth from the carrier to one edge.

>>  2.  You can probably do better on KSL by getting the radio off the ground and orienting it toward Salt Lake...or away from KCBQ.

As for getting it off the ground, I know from experience that simultaneously holding and operating a radio AND a camera is NOT easy. :)

Reorienting - I chose KSL and that particular location for multiple reasons...  KSL was chosen because it doesn't have a day/night pattern change, being a 50kW clear channel.  (My other possible choices, 1150 KTLK, 1180 KERN, 1190 KGBN, which would have been about in the same azimuth as KCBQ from there which would have been preferred for the test, all do their pattern change at the same time as KCBQ at this time of the year.)  Also that location was chosen, in part, because KCBQ shares their transmitter site with 910 KECR (who was actually there first).  I wanted a location where KCBQ had a very strong daytime signal, but KECR's signal was relatively weak owing to different back nulls/lobes in their patterns, limiting the blocking/desense caused by KECR.  (I was southeast of them, and both stations' main lobes are aimed southwest.)  Also if I chose a location where KSL would have been on the same azimuth as KCBQ, KECR's signal wouldn't have been
 enough weaker than KCBQ to enable KCBQ to be very strong with KECR being relatively weak - KECR still would have been moderately strong.

>>  ++ If your goal was to observe comparative signal strengths...I wouldn't bother.  I never rely on signal readings on any radio, but instead just go for what's coming out of the speaker.  As you've noted, signal strengths can be so arbitrary and, depending on the radio, can actually be misleading.

>>  Finally...that close to a 50-kilowatt signal, some radios simply go into overload and all bets are off.  That didn't sound like the case with your PL-606 but it is a problem with some radios.

It may have gone into front end overload (blocking/desense, manifest by the 50/00 reading while KCBQ was at full power and KSL not being audible at all - it goes away when KCBQ's transmitter shuts off for several seconds starting around 0:53, revealing KSL and XEQIN), but it was nothing compared to what you would see in my other two videos linked in the message. ;)

>>  Please forgive, if I'm just re-stating the obvious <g>

You're forgiven, although I don't really know if all of what you stated was "obvious". :)

>>  Regards,

>>  Mark Durenberger

--------------------------------------------------
From: "Stephen Airy" <pianoplayer88key@xxxxxxxxx>
Sent: Tuesday, December 06, 2011 11:31 PM
To: <irca@xxxxxxxxxxxxxxxx>
Subject: [IRCA] PL-606 odd behavior in Lakeside, CA recently

> Hi all,
> 
> I was in Lakeside, CA, yesterday, and recorded a video clip of what happens when I try to receive 1160-KSL at around local sunset using my PL-606.  I did mention a few things in the video's description...
> 
> http://www.youtube.com/watch?v=7eQql8niXLE
> 
> Is there some internal modification I could try so that I have the same quality of reception as from 0:53 to about 1:00 or so as at other times (while realizing the variability of skywave)?  It'd be a bonus if reception would also be like that a couple miles to the northwest or so. ;)
> 
> 
> Also a month ago I recorded these two videos.
> 
> http://www.youtube.com/watch?v=fEMLcEqCu3E
> http://www.youtube.com/watch?v=kEIU3mP5f38
> 
> Anyone have any idea what's going on, specifically, especially when I put my radio & SAT up to the utility pole?  ("Overload" isn't descriptive enough - is it front-end, detector, audio rectifying signal bypassing RF/IF stages, etc - what (technically?) is happening?)
> 
> Thanks for any education that can be sent my way. :)
> 
> 73,
> Stephen
> 
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