Magnetic field of a relay

Yes that is the general idea. In case of an antenna feeding the DC could be made by using a twin wire for the antenna and the RX/TX coils and applying the DC between the 2 wires from the cold end with decoupling capacitors to ground. Thanks for the interesting links.

Little confused, but what I understood was, instead of a single antenna wire run a pair and use one as the DC return. If that's what you meant, I like that a lot. I am already using a pair of wires, it is army surplus phone wire WD-1, so it's easy. I've made a new drawing incorporating the idea, but now, I'm not sure where the RF chokes and the DC blocking caps need to be. If I have them wrong please comment. Here's the drawing.

Which of the article peaked your interest, I may have others.

Thanks, Mikek

Given that with this setup the radio signal is common-mode and the control signal is differential: my take is that the variable inductors should be wound with both wires in the same direction, as the RF inter-winding capacitance isn't a problem they can be wound bifilar for ease of construction

The magnetising windings could be wound with both wires in opposite directions, and a pair of bypass caps across the magnetising winding).

Or you could just use a single winding either shunt across the wires, or in series with a single wire.

. . ____mmmmmmm_____________||_______ ____mmmmmmm______________ . | || | . ____mmmmmmm______||___|____|_____ ____mmmmmmm______||______ _______| || | | | _______| || | (_ | | | (_ | (_ | | | (_ | (_ | | | (_ | (_o__________| | | (_o__________| ______________| | (_o | (_ | (_ | (___________________|

. ____mmmmmmm___________ . | ____mmmmmmm_______|___ _______| | (_ | (_ | (_ [R] ? (__________|

--
  When I tried casting out nines I made a hash of it.

Thanks for the nice ASCII art. Yes that's exactly what I had in mind. Both cables are shorted at the open end in case of serial wiring of the control current. The idea is not limited to 2 conductors. Just an even number for balance. Ethernet cable can be used for antenna if weather resistant.

[...]

It does cost efficiency though, depending on where the inductors are.

The All-American solution for this challenge: Buy a bigger property 8-)

JFTR I had a vertical for the 80m band with a substantial coil in there. When pumping a little over a kilowatt into it (legal in Germany back then) ... *PHUT* ... chingalingaling ... the upper rod rolled down the roof. Then I crammed an inverted vee onto the limited lot and its efficiency was a lot better.

[...]

--
Regards, Joerg 

http://www.analogconsultants.com/

I had a Hy-Gain 18AVT vertical with a matching coil at the bottom for

80m band, due to the limited space on an apartment house roof.

At about 200W into it, the top hat started to create corona, looking like a plasma sphere in the dark.

--

-TV (OH2UG)

That could happen with the Fritzel GPA5 as well. It had a short slide-in rod up top and you had to adjust that for your preferred section of the

80m band. The clamp to hold it in place had to be nicely rounded and sanded at the edges or you'd get corona.

--
Regards, Joerg 

http://www.analogconsultants.com/

I would still have the 3 to 1 frequency range of our AM band to tune for.

Power is not a problem, it's a receive only antenna. I'll give up efficiency for directionality. The going word is that BOGs are low level antennas, maybe, but it had a signals as high as my 150ft long wire at 30ft and an amplified miniwhip, as shown in my comparison video.

Mikek

Mike, a 150ft wire is not a long wire at MF. The wavelengths of MF broadcast band are 600 to 2000 ft. To be qualified as a long wire antenna the wire has to be several wavelengths long.

--

-TV

Exactly 85 out of a 100 people would call 150ft antenna a long wire antenna. I believe it is a convention. I have never heard of a shortwire antenna. But I do understand that AM has long wavelengths. I could call it a random wire antenna.

Mikek

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There are small magnetic loop antennas. They need to be 1/6th the waveleng th or so to work as a "small" loop which is not the same as a larger loop.

At least for transmitting loops seem to have a bunch of trade offs which ma ke the design a compromise. But I suppose that's true for all antennas.

I can't say I understand a Beverage antenna. A Beverage can be two wire or use ground as the return path. If using a two wire and the signal is comi ng from the resistor end, wouldn't the two wires pick up the same signal an d essentially cancel? The wikipedia page shows an animation of a one wire Beverage (BOG?) which makes more sense. I believe your antenna is grounded at the resistor end making it a BOG, no?

--

  Rick C. 

  -+ Get 1,000 miles of free Supercharging 
  -+ Tesla referral code - https://ts.la/richard11209

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ngth or so to work as a "small" loop which is not the same as a larger loop .

I have built a few loops, I have 2ft 14 turn loop with azimuth adjustment, but rarely use it. I also had a rotatable, variable termination Flag antenn a for many years.

make the design a compromise. But I suppose that's true for all antennas.

No, a Beverage is a single long(500 to 2000ft)wire 6 to 10ft off the groun d. They talk about wavelengths, so 1/2 to 2 wavelengths long. I suppose you could run a ground or counterpoise under it, but not many do. It can be terminated for a null off the opposite end (transformer end) or l eft open for to receive in both directions. They can also be setup so the direction is switchable, with the proper tr ansformers.

Since they don't get the same signal, and VF is different, the signals are not exactly the same. But, I have not read about anyone running a counterpoise under a beverage.

The wikipedia >page shows an animation of a one wire Beverage (BOG?) which makes more sense. >I believe your antenna is grounded at the resistor end making it a BOG, no?

I don't see any BOG on the Beverage Wiki. A BOG is on the ground, a Beverag e is in the air. The resistive termination makes the beverage and the BOG d irectional. Sorry about the Google post, I could not see text in your post, so went to google groups to see it. Mikek