[Lowfer] HiFER AZ at 13.554415 (plus KFI & friends...)

[Clint Turner]

Hi,

>I've looked for AZ a number of times, but haven'tt caught it. But I've been
>looking at 13554.5, though that shouldn't make much difference for CW. Will
>have to try again.
>
>  
>
Maybe lucky, I guess.  I was surprised to hear something on such a short 
path - but then again...  I'd almost missed it, because I wasn't looking 
for it and finally it occurred to me that the beeping noise I was 
hearing was, in fact, AZ.  (I didn't have my grey-matter RX tuned in at 
first...)

>There's a LOT going on in those 640 kHz screen shots. Wow. Would be
>interesting to ID some of the other players. I think the sawtooth just comes
>from thermal control, either of a crystal oven or of a building's
>ventilation.
>
>  
>
I'll have to try another receiver.  I tend to use my FT-817, as that's 
the most stable DDS-controlled RX that I have (I have a DDS VFO for my 
TR-7, but that entire thing takes a few hours to stabilize.)  There is 
be some audio IMD appearing:  If the Noise Blanker is on, it appears (of 
course...) but another thing that makes audio IMD pop up is AGC action - 
which makes sense, actually.  Although it's hard to gage, the IMD is 
actually 40+ db down according to Spectran and is generally identifyable 
by it's behavior.

I looked to see what else is on 640 that could account for the other 
"activity" in the plot.  Go to:

http://www.fcc.gov/mb/audio/amq.html

and select 640 KHz for both the upper and lower frequency:

And I was surprised as to the possibilities.

- A 10/1 kW in MT
- A 10 kW in AK
- A 25 kW in FL
- A 10 kW in NF (CA)
- A 50 kW in ON (CA)
(Anyway, you can see...  there are a grundle more than these - a lot of 
them being in Mexico and lower power.)


>Will have to check for KSL. They are on the 2nd harmonic of the station I
>used to work for, so I remember the fun in monitoring that frequency. They
>are the biggest thing on the channel, though.
>
>John Andrews
>
>
>  
>
It (KSL) is, of course, one of the strongest things here:  Their main TX 
ant is a single 5/8 wave vertical with a massive buried groundplane 
system in extremely salty soil (they are almost next to the Great Salt 
Lake.)  Supposedly, their radiation efficiency/launch angle is about as 
close to theoretical as one could hope for!  At night they actually run 
suppressed-sidedband AM (they attenuate the LSB, I think...) and because 
of this their PEP is actually a bit over 200 kW owing to this 
asymmetry.  (It's called "PowerSide" I believe...)

Their frequency control is a homebrew synthesizer (built by WB7CAK, 20+ 
years ago) that uses some HP ovenized reference (in a bell jar, I 
understand) and they've used this on every transmitter since.  I was 
told that they constructed this when they were involved with some sort 
of (then) NBS program (from the late 70's or early 80's) to use AM 
stations as frequency references and this system is a remnant of that.  
I guess that in the intervening decades the reference has been drifting 
down in frequency a bit...

***

>KSL appears to be about 30 mHz lower than seen by Clint, probably daytime temps.
>
>Dale Rice


I haven't measured it in the daytime myself - but it could be that a 
measurement uncertainty could account for this.  As for my 
frequency-measuring technique, it's two-step:

- I generate a signal on a known frequency.  I use a GPS-referenced 
service monitor for this (a Schlumberger 4031.)  Over periods of 
measurement this long, it's stability is that of the GPS receiver (an 
HP-3801A.)
- I measure the difference between the unknown and known (by measuring 
the audio frequencies in Spectran) and do the math.

At least with Spectran (this version) my resolution is only 0.021 Hz, so 
I could have at least that much error on the two different points.  
Perhaps I need to run ARGO for more resolution:-)

Clint