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75M Drifting Buzzy DF'ed to Maine




 
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Author Topic: 75M Drifting Buzzy DF'ed to Maine  (Read 4951 times)
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K1JJ
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"Let's go sailing, Tommy!" - Yaz


« on: February 22, 2005, 10:54:58 AM »

Hi All,

There's been a loud, 60hz type drifting buzzy on the 75M band for many months. Sounds like an industrial  lumber heater/dryer oscillator or something like that. Raw oscillator. It drifts up and down the band as as much as + - 200kc at times. It has a tendency to SLOWLY crawl its way across 3870-3890 and take out AM QSOs at times.

A few weeks ago, Pete,  W1VZR called the ARRL about it and got a call from Riley looking for more info. They were unable to hear it for some reason.

Well anyway, today I heard the guys complaining about it and I decided to do some DFing.  Sometimes conditions are perfect for DFing and I can zero in on the location quite effectively for distance and heading. Using the beverages, local dipole and directional arrays I found it to be in Maine near the Lewiston, Portland or Gray area.   This is about 300 miles away, so figure on some + - tolerance...  :grin:

Anyone who lives in that area might take some S meter readings. The best type are like:  Tron in Skowhegan Maine is S9+30 and the buzzy is S9+20.  Pete in Limerick Maine is S9+25.  W1XXX in Concord New Hampshire is S9.  This tells a lot for relativity.

Anyone having a portable radio with a loopstick can also help immensely since we have it pin pointed to a general area, but not cross triangulated yet.

Please post these readings here and we will forward them to the ARRL. This will help put it right on the mark and a knock on the door.

73,
Tom, K1JJ
Marlborough, CT - 20 miles SE of Hartford
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
K1JJ
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« Reply #1 on: February 22, 2005, 11:57:46 AM »

Quote from: K3MSB

Tom --
I'm curious as to exactly how you get the distance.  With any kind of DF system, you need at least 3 bearing cuts to determine any kind of accurate range to target.   2 Won't be very accurate and the 3rd is needed to bound the area of uncertainty.  So, assumming the antennas are all at your QTH, the measurement baseline is going to be pretty darn small.   You'd need pretty accurate bearings to get an accurate position fix.  I'm interested in how you get the accurate bearings.


Hi Mark,

Good questions...

Well, it turns out that much of the distance measurements are based upon a combination of things.... high angle/ low angle antenna choices, the time of day (11 AM signal attenuation), Maine's unique postion near the ocean (no population to the east of it, and my experience doing this over the years with these same antennas.

First of all, for the heading, the buzzy is LOUD to the NE on both the NE terminated beverage and the high 2el Quad to the NE. It is weak on all other beverages and directional arrays.  It is also louder on the NE quad than the lower single dipole at 80' (The dipole is broadside to Maine).  This tells me it must be in Maine or farther, cuz the high quads at 190' are low angle and unless you at in southern Maine or farther, the dipole is ALWAYS louder. I also know from experienece that central  Maine will start to drop out at around  11AM on 75M from listening to Tron. So it is not in northern Maine or Nova Scotia, etc.

The NE quad shows no gain into NH and VT most of the time and the dipole is always better there..   The angle to NH/VT is also very high and makes the NE quad weaker.

The high 2el SE quad shows a BIG side rejection to the buzzy which is another confirming fact that the signal is low angle, meaning at least as far north as Maine.  At this time of day it is much easier than at night since signals attenuate very quickly and you can cap the max distance. However at night, multiple skips can come in at low angles and give you a tougher time.

The next step is triangulation with the locals..

73,
T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
WA1GFZ
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« Reply #2 on: February 22, 2005, 01:20:39 PM »

Oh don't you use North Reference Pulse to return pulse? for range???
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K1JJ
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« Reply #3 on: February 22, 2005, 02:09:00 PM »

Quote from: WA1GFZ
Oh don't you use North Reference Pulse to return pulse? for range???


Yes, of course, Frank...

I used that setup to zero in on the intruders location. I selected a Time-Bandwidth Products model GE-100-VAN-HP neodymium-doped yttrium orthovanadate crystal (Nd: YVO4) laser as the illumination source. The laser is diode-pumped, passively mode-locked (using a saturable absorber), and produces 1.5 KW of output with a pulse width of 45 ps and a repetition rate of 40 MHz. The 1.06 μm wavelength of the Nd: YVO4 laser is not considered eye-safe, but who cares - But I will possibly replace it with an erbium-based laser operating at a wavelength of 1.5 μm.

The EO modulator used in this DFing JS is external to the laser cavity and controlled by an Agilent Technologies model 81104A pattern generator. I aimed for the targets downstream of the laser aperture where their surfaces will scatter the beam. The scattered return is detected by an amplified Newport Corporation indium gallium arsenide PIN detector. Using this very strapping but JS DFing setup with targets no more than  300 miles away, collection optics are not necessary, although they will be needed for studies over longer ranges.

T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
W8ER
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« Reply #4 on: February 22, 2005, 02:38:40 PM »

JJ said:
Quote
First of all, for the heading, the buzzy is LOUD to the NE on both the NE terminated beverage and the high 2el Quad to the NE. It is weak on all other beverages and directional arrays. It is also louder on the NE quad than the lower single dipole at 80' (The dipole is broadside to Maine). This tells me it must be in Maine or farther, cuz the high quads at 190' are low angle and unless you at in southern Maine or farther, the dipole is ALWAYS louder. I also know from experienece that central Maine will start to drop out at around 11AM on 75M from listening to Tron. So it is not in northern Maine or Nova Scotia, etc.


Damn if I'll play "Clue" with you!  :lol:

--Larry
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W1GFH
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« Reply #5 on: February 22, 2005, 04:01:16 PM »

Got a WAV file of this buzzy?
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W3SLK
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« Reply #6 on: February 22, 2005, 10:56:19 PM »

What's the possibility that it may be emanating from Belgrade Lakes??? :badgrin:
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Mike(y)/W3SLK
Invisble airwaves crackle with life, bright antenna bristle with the energy. Emotional feedback, on timeless wavelength, bearing a gift beyond lights, almost free.... Spirit of Radio/Rush
K1JJ
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« Reply #7 on: February 23, 2005, 01:04:03 AM »

Joe,

I don't have a .wav file of it at this point. Maybe someone is set up to do one and can post it. But, it sounds like an unstable and raspy 60 hz parasitic drifting across the band.

Mikey,
 Yes, Belgrade Lakes in in that area....  :grin:   But, I'd put my money on some industrial complex with a Boss Hogg looking owner who acts stunned when he's told his arc gap transmitter is being heard 300++ miles away...

T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
W1GFH
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« Reply #8 on: February 23, 2005, 01:53:01 AM »

Quote from: K1JJ
Joe, I don't have a .wav file of it at this point. Maybe someone is set up to do one and can post it. But, it sounds like an unstable and raspy 60 hz parasitic drifting across the band


Reason I ask is, it may be the same thing I use to have RFI from (and it sounds like it could be, which is why I wanted a WAV file), i.e. a battery charging system that is part of a large solar array w/ power and control lines in the air, resonant length same as 75M.
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WA1GFZ
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« Reply #9 on: February 23, 2005, 08:06:01 AM »

Tom,
I was throwing ARN84 TACAN crap at you. Remember that system
we worked on at the sweat shop?
GFH So. Ca. is one big buzzie.  Stay dry!
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KB1KFI
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« Reply #10 on: March 01, 2005, 09:28:50 PM »


Rumor has it, it is a halliburton(sp) project...
Very hush hush(ha-ha)!
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KB2WIG
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« Reply #11 on: March 03, 2005, 07:08:36 PM »

... didnt know they made a Super Pro
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