petitnjbuild a 1/4 wave vertical out of a SO-239 panel mount connector and 5 pieces of welding rod or metal clothes hanger...
Simple, it works, and yes, elevation is everything.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
build a 1/4 wave vertical out of a SO-239 panel mount connector and 5 pieces of welding rod or metal clothes hanger each 18.5 inches long. One goes in the center vertically and the other 4 on each of the screw holes out at about a 30 degree angle down. See https://www.youtube.com/watch?v=Vxft-rYHGDw&list=RDCMUCC2RJ3tINAiKEH9X_ijo1Yg&index=1
And remember that elevation is everything. Get it as high as possible; elevation overcomes the coax loss and grows your range.
IbanezGuiness Please post your results.
Please post your results.
It'll be next week, anyhow. I have a fire department event this weekend that will keep me busy.
IbanezGuiness Do you have an antenna analyzer to test yours when you get it finished? I'm curious to see how it resonates at the railband.
Do you have an antenna analyzer to test yours when you get it finished? I'm curious to see how it resonates at the railband.
I do - I'll have to get it finished and on the air.
wkrass tree68, Thank you for the dimensions. This should be a fun project in the near future. Wayne Krass
tree68, Thank you for the dimensions. This should be a fun project in the near future. Wayne Krass
My pleasure.
As is pointed out in some articles about this antenna, you can easily hide it, even under a dishpan, in one example.
I've wondered about obtaining a glass ball (not mirrored) to fit in the middle, making the this slot cube antenna into an objet d'art - again potentially useful if you have HOA restrictions on antennas.
For the adventurous, information is available on-line for turning satellite dishes into slot antennas. Most HOA's don't object to them.
If anyone builds either a slot cube or a J-pole, please be sure to come back and share how it works out for you.
blue streak 1 Tree any chance any of these antennas are fractal antennas ?
Tree any chance any of these antennas are fractal antennas ?
To be perfectly honest, I had to look fractal antennas up. Neither the slot cube nor the J-pole would qualify, I don't think, but if someone has the wherewithall to design a fractal antenna that would also serve as wall art in their living room, more power to them.
Here's the basic cuts for a two meter slot cube:
4 Each 8.5"2 Each 8"2 Each 7"2 Each 6"2 Each 3.5"2 Each 1"Gap in CPVC connector is 1/8"10 Each 90* Elbow2 Each "T" Fittings
For receive only, those dimensions will probably work fine. I haven't tested mine to see where it resonates yet.
There are on-line calculators for building J-poles. Just plug in the desired frequency and it will give you the lengths for the pipe and the feedpoint location.
I do recommend that you use electronics solder to assember either one, as opposed to pipe solder. I had much better results with some 63-37 solder.
Some guestimate calculations suggest that if you multiply each of the dimensions for the slot cube by .9184, that should bring the frequency up to the 160 MHz range. Bear in mind that's just my guess. The only way to find out if it resonates at 160 MHz would be to build it and put an antenna analyzer on it.
The next question with those revised dimensions would be whether the parts would actually still all fit.
If you're going to build the slot cube for receive only, just go with the original dimensions.
tree68,
The article does not give the dimensions for rr frequencies without joining the ham group. Can you provide the materials list with those dimensions? Thank you, Wayne Krass
Another copper pipe possibility, a little fussier to construct than the J-pole, is the slot cube: http://www.w6nbc.com/articles/2019-01QSTcubeslot.pdf This one will also tune up for VHF-Hi and UHF. And you can always pass it off as copper pipe sculpture... I've got one almost put together, but not quite ready for the air yet. I should mention that I'm an amateur radio operator.
This one will also tune up for VHF-Hi and UHF. And you can always pass it off as copper pipe sculpture...
I've got one almost put together, but not quite ready for the air yet.
I should mention that I'm an amateur radio operator.
Regards - Steve
How handy are you with plumbing skills?
For $10-15 in materials, plus coax, you can build yourself a "j-pole." You can find the instructions on the web. Half inch copper pipe (10' piece), a tee, an elbow, and three caps and you're on your way.
And you'll find variations as well.
I know of one fellow who turned J-poles into lamps - handy if you live in a complex with restrictions. You can put it on your balcony and no one is the wiser...
If you build/tune it for the railroad band it will give respectable performance on VHF-high and UHF.
Once you get it built (or otherwise acquire an antenna) your goal will be as much height as you can get.
What kind of budget are you working with?
What is the terrain like where you live?
Are you on a hill or in a valley?
Do you signals you want to receive come from all directions or one?
Going to put a base antenna up so I can listen to train traffic,What is a good one to buy?
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