• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

Care and Feeding of new 'Longwire'

Steve Green NEPA

Steve Green NEPA

I'm considering the -- you should excuse the expression -- erection of a longwire antenna for AM and some SW reception here in a fixer-upper place I'll be occupying for a while. And since I never knew the basic principles in the first place, even before relocating to a region that's called The Land Time Forgot, any help would be welcomed. I estimate that there'd be room for something like 80 unfurled feet of stout wire, from a second-story window stretching somewhat uphill to the back of the property.

a) The wire would stretch just about due North-South. I should think that, at its 24.3 meters in length, it would that provide most excellent reception on the 49 meter band since it's double the wavelength and would be twice as potent. Yes/no?

2) Ceramic standoffs? At both ends, maybe? See, my naive non-tech tutelage suggests that an antenna is like a levitating, pristine gadget that has to be tapped so its basic efficiency isn't compromised by any unnecessary loss during siphoning. Am I way off here?

c) *If* that wavelength resonance stuff is an accepted 'given', my math suggests that 24.3 meters -- half of 160 feet wavelength -- would mean nice electromagnetic reinforcement mostly in synch with the top of the AM dial, with the X-banders and TIS stations. T/F?

d) Don't syh, please. I never figured out what Grounding was for or what it did. But it sounds important. Which end gets grounded? Both? Just the end that's in the upstairs window where the radio will be? I've seen a pal of mine's setup, long ago, where his longwire got fed into the radio room window with some sort of coax strap.....

5) Lightning arrestor? How, why, where, and at what $$$$? See, the planned radio is a refitted HQ-180 that set me back 5 pigs and it would be a nuisance if it became a $500 pile of solder after a storm. Do I disengage all antennae and unplug it when it's not in use?

Give me some homework here if'n when you find the time, oke? T.i.a. !
 
I don't have any experience with longwires, but the IRCA and NRC both have a lot of technical articles available on the website.
 
Radio needs to be grounded. Not the antenna. Either put a lightning arrrestor in or disconnect (what I do) when not in use. As long as you do not intend to transmit, use what ever length you can fit and get it as high as possible. I am told that a counterpoise would be useful for reducing RFI, but I have never done that. I had forgotten about the pulley and the brick. I do see there are a lot of YouTube videos for long wire antennas. You might want to start there and watch a few to get acquainted before going to more detailed instructions
 
I still remember back in the late 60's when my older brother had a long wire running out the window and along the roof for his shortwave radio and a lightning strike destroyed the wire.

The radio had to be repaired.
 
So I take it that a lightning arrester is a SEPARATE object that is not part of the antenna or hooked up to it, or to the radio?

I also interpret the words here as meaning a lightning arrestor should be placed higher up than the antenna and act as THE target. In what form does a lightning arrestor assume? Can I make one myself? How far or near is ideal for one to be proximate to the longwire to 'protect' it?

Again, tnx in advance!
 
The lightning arrester we had for our TV antenna years later was installed near the ground right where the antenna wire went into the den window.

It was 300 Ohm wire for TV in those days.

I don't know where it would be placed for a long wire antenna or even if there is such a thing specifically for that.
 
When I was in the Air Force I helped one of the MARS guys set up a sight for an open house at the former Carswell AFB. Right before the rig he had 3 three foot loops of the antenna cable in a row. He said it was giant inductor which he said lighting hated.

IMHO you can predict lightning's 99% of the time but that 1% happens too frequently.
 
Steve Green NEPA said:
So I take it that a lightning arrester is a SEPARATE object that is not part of the antenna or hooked up to it, or to the radio?

I also interpret the words here as meaning a lightning arrestor should be placed higher up than the antenna and act as THE target. In what form does a lightning arrestor assume? Can I make one myself? How far or near is ideal for one to be proximate to the longwire to 'protect' it?

Again, tnx in advance!
Click to expand...
The lightening arrestor generally is “in line” with the antenna lead in to the house or apartment, with a wire going to ground (water pipe or a ground rod, etc.). It is usually about the size of a wall wart with a lead in and lead out connector. There is also a connector to go to the ground I referred to.

Note: there are some antennas that do have a ground at one end, but these are wavelength Beverage antennas, which can be 1000 feet long or more.

As mentioned, both the NRC and IRCA both have papers about different kinds of antennas.
 


Back
Top Bottom