60v p-p rf
60v p-p rf
I put a scope on my long antenna and it reads 60 volts peak to peak RF from local AM stations.
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Tony
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Re: 60v p-p rf
In the old days, people living near strong medium wave transmitters used to light their gardens with lightbulbs and later fluorescent tubes connected to wire antennas although it was officially a crime. We still have a law against "theft of electrical energy".
Ralf
Ralf
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Re: 60v p-p rf
In the other thread (longwave sensitivity) you mentioned 6 volts P-P and possible damage to your RSP. I posted the safe levels for the RSP there.arcosine wrote:I put a scope on my long antenna and it reads 60 volts peak to peak RF from local AM stations.
Roger
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Re: 60v p-p rf
60Vpp = 10Wpeak!!
That is a lot, how close are the AM-stations? You must be about right under their antenna.
Are you sure this is all coming from the antenna? And not between antenna and grounding or such.
That is a lot, how close are the AM-stations? You must be about right under their antenna.
Are you sure this is all coming from the antenna? And not between antenna and grounding or such.
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Re: 60v p-p rf
He wrote in the initial post that he gets 60 Vpp at his scope's input, so presumably with a very high load impedance. I suppose that with a load impedance of 50 ohms the voltage would be far lower.
Ralf
Ralf
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Re: 60v p-p rf
I found that my scope 10v/div setting is not right,oxidized contacts. Its only about 6 v p-p, unloaded, hi Z. Antenna is about 3k ohm impedance.
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Tony
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AA9CC
Re: 60v p-p rf
As a new oscilloscope owner, I'm curious about the details of how you hooked this up. I know my scope has 1-megohm inputs, so for most RF devices including my antennas it's necessary to add a 50-ohm feed-through terminator. Did this also apply in your case? Also, I'm not sure if I recall the details of your antenna -- is this a longwire, with the measurement between its feed point and ground? Or a dipole?arcosine wrote:I put a scope on my long antenna and it reads 60 volts peak to peak RF from local AM stations.
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Re: 60v p-p rf
I used the scope input and the antenna is a 900 ft wire grounded far end at lake, between 5 and 20 feet high, running approximately northwest. Like any loop its directional. About 3k ohm at MF/LF. DC loop resistance s about 50 ohm, mostly from wire, .03 aluminum welding wire. I have ground stakes at both ends and 75 ft of 300 ohm lead into the shack. The matching transformer is 8 turns primary one turn secondary on ft-87A-F core, Also have 30 turns to a 500 pf variable for tuning.
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Tony
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Re: 60v p-p rf
Thanks for the info. I was curious specifically how you connect the antenna to the scope input. (I.e. what cable and/or connector are you using between the scope and antenna.) Also, which scope are you using?arcosine wrote:I used the scope input and the antenna is a 900 ft wire grounded far end at lake, between 5 and 20 feet high, running approximately northwest. Like any loop its directional. About 3k ohm at MF/LF. DC loop resistance s about 50 ohm, mostly from wire, .03 aluminum welding wire. I have ground stakes at both ends and 75 ft of 300 ohm lead into the shack. The matching transformer is 8 turns primary one turn secondary on ft-87A-F core, Also have 30 turns to a 500 pf variable for tuning.
Reason: No reason