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Author Topic: Power Line Noise problem: K9AY Loop vs 500 ft Beverage- is one less susceptible?  (Read 22860 times)

Posts: 2218


« Reply #15 on: February 11, 2013, 09:06:22 AM »

You can design or build and adjust a short beverage for a cleaner pattern than a long one.  There are preferred lengths for getting a good pattern--so I tweaked my half wavelength beverage for a good front/back--it dropped 6Y5WJ from loud to in the noise on 80M.   Grin

I'd like to model your short Beverage antenna sometime, Zack. Exactly how long (and high) is it?


Posts: 2667

« Reply #16 on: February 11, 2013, 10:40:11 AM »

According to EZNEC models I made, I discovered you could compensate for the length of the wire by adding some reactance in series with the termination resistor.

My Beverage is a half wave on 80--about 5 feet high, running over a hedge, rose bushes, then more rose bushes/forsythia next to a chain link fence.  Hardly ideal, but I tossed it up and it seems to work quite well.  Actual length turned out to be 132 feet of #28 polyethylene covered wire--measured by pacing it off.  It has a 430 ohm termination and 4 ft ground rods at either end.  I thought I had more wire, but I've learned that you should try it out and see if it works.  I didn't do any actual adjustment--there was and still is still snow on the ground--right now either end is buried deeply in snow--we just got 28 inches Cheesy

« Last Edit: February 11, 2013, 10:49:37 AM by W1VT » Logged

Posts: 5

« Reply #17 on: February 13, 2013, 12:17:05 PM »

Power Line Noise resolved.  The local utility came by and we tracked down the  source....a continually arcing lightning arrestor with the rubber boot around the spark gap blown in half.  Noise has now dropped to a much more manageable S-5.  but it uncovered a whole family of pops,  crackles and  tick tick ticking sounds I never heard before. Smiley  But at least 160-80 and 40m are now fn to operate again.

Utility linemen were great to work with and did everything I asked.  Actually finding a source     ( that was also costing them money)  didnt hurt either.  IE do your homework first and just guide them to the pole or poles in question.  Make sure they go up top and inspect adn ticghten ALL the hardware.  In our case I could see they  gave some  loose through-bolts  some extra cranks.  BTW  The line carried 3 phases of 7200v on steel poles.  They also voluntarily  changed to  phase  in question's  top insulator.  And the guys  advised  anytime a tree has branches or twigs  touching their lines it will usually result in substantal RFI.  So if you see lines running through trees, report it and action will be taken.  They will first ask the homeowner IF they can cut back the tree.  In our case, they were denied,  and backed off, instead reporting the problem to HQ for legal action.

Good luck with  your PLN. Utilities are cooperating!

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