Ham Radio Antenna?

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jahilliard

Senior Member
I have a customer that needed a circuit added for an Hf Power Amplifier fro his Ham radio equipment. Apparently he uses his pool cage as part of his antenna. He was told that his pool cage was probably not performing as well as it should because the poor continuity of the aluminum pieces of the cage, and to solve that problem as soon as possible. He asked us to help out with that and my first GUESS would be to bond the pieces of the cage where needed BUT I do not want to do something I have no clue about, therefore potentially creating a giant lightning attrator that will send a million volts to his expensive equipment...and I am not saying that's what I am creating but I just want to have some insight about how this works, can be resolved, etc.
 

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Registered Professional Engineer
Exactly what it sounds like:
https://duckduckgo.com/?q=pool+cage&t=opensuse&iax=1&ia=images

What part of the antenna? If he's using the pool cage for a ground plane, you can improve performance by installing an aluminum disc (radius similar to or greater than wavelength) under the antenna and ground straps extending outward from the center to a good Earth ground, but it'll look very hokey. If he's using it for the live part of his antenna, I would apologize, say that your expertise doesn't extend beyond 400 Hz, and back away.
 
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K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I have a customer that needed a circuit added for an Hf Power Amplifier fro his Ham radio equipment. Apparently he uses his pool cage as part of his antenna. He was told that his pool cage was probably not performing as well as it should because the poor continuity of the aluminum pieces of the cage, and to solve that problem as soon as possible. He asked us to help out with that and my first GUESS would be to bond the pieces of the cage where needed BUT I do not want to do something I have no clue about, therefore potentially creating a giant lightning attrator that will send a million volts to his expensive equipment...and I am not saying that's what I am creating but I just want to have some insight about how this works, can be resolved, etc.

Have your customer post his question on QRZ.COM. There are a couple ham radio antenna gurus that frequent that thread. FWIW, I have never heard of a 'pool cage' or anything of the sort. I wish I could be of more help, but that's a new one on me, and I have been licensed continuously since 1994.
 

mgookin

Senior Member
Location
Fort Myers, FL
A pool cage can not sustain a snow load.
That's why y'all yankees have never heard of one.
It's a southern thing y'all. :)

It's an aluminum framed structure, most commonly sharing a common wall with a building, often a single family home, with screening as the wall and roof panels.
They keep the bugs off the people and the leaves out of the pool.
When you see news video of storms ripping through south Florida and you see those piles of aluminum framing and screening, those piles used to be pool cages.
 

cpinetree

Senior Member
Location
SW Florida
A pool cage can not sustain a snow load.
That's why y'all yankees have never heard of one.
It's a southern thing y'all. :)

It's an aluminum framed structure, most commonly sharing a common wall with a building, often a single family home, with screening as the wall and roof panels.
They keep the bugs off the people and the leaves out of the pool.
When you see news video of storms ripping through south Florida and you see those piles of aluminum framing and screening, those piles used to be pool cages.

Yup a pool cage keeps the pool from getting out, never feed the pool when its in its cage :happyno:
E30.jpg
 

mtfallsmikey

Senior Member
Have your customer post his question on QRZ.COM. There are a couple ham radio antenna gurus that frequent that thread. FWIW, I have never heard of a 'pool cage' or anything of the sort. I wish I could be of more help, but that's a new one on me, and I have been licensed continuously since 1994.

Greenhorn!... I've been licensed since 1970! :p
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Clearly we need a radio and communications sub-forum :)

(newbie: licensed last September)

73
Jon
AF7TS

Congratulations! Tech to Extra in 3 months!

It took me over a decade!

But, I had a VERY hard time with the code (Morse, not the NEC) and it wasn't until my daughter helped me with it that I finally got the 'ear' for it. The written tests were way easier for me than the code test.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Hopefully the OP will return.

What I would like to know is how a pool cage is supposed to perform.

He was told that his pool cage was probably not performing as well as it should because the poor continuity of the aluminum pieces of the cage, and to solve that problem as soon as possible.

What kind of problem is he trying to solve?

SWR too high?

A sudden change in RX/TX quality?

RFI?

Not being able to break pileups during contests?

Eaton AFCI breakers tripping when he transmits on 17 meters?

What's supposed to happen if he doesn't 'solve the problem as soon as possible'? Damage to his radio or amplifier?
 

jahilliard

Senior Member
I apolgize for being gone so long...I'm still ot real clear on what the "problem" exactly is. Has something to do with too much current coming back onto his cable and destroying his amplifiers. I guess High Voltage goes out and High Current is received...or something like that. He had me place some #12 Cu Stranded out along the ground at 54' (length is determined by the frequency or maybe wavelegth I believe) and another in a differet direction at half that distance. I guess it helped a little...I did what the guy wanted simply out of curiosity. Like I said I'm still pretty lost as far as explaining wth I was actually doing for the antenna. He also asked me to test the resistence around the Aluminum Structure that prevents bugs and leaves from entering the Pool aka "Pool Cage"...it had great contunuity IMO at .1 Ohms from every location I checked.
 
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grich

Senior Member
Location
MP89.5, Mason City Subdivision
Occupation
Broadcast Engineer
... Has something to do with too much current coming back onto his cable and destroying his amplifiers...

Does sound like he's got too much reflected power coming back to his transmitter. If he has that bad of an impedance mismatch I don't think your bonding efforts will be of much help. He's got a bigger design problem.

Pictures would help. :) Turning it over to the QRZ forum would be good as K8MHZ suggested.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Edit to add: I see you are on the 'Zed, too. Good posts.

Thanks! I joined the Zed at your suggestion :)

The Extra thing just meant that I really should have started earlier. I had all of the theory from work and other hobbies; had been soldering circuits together since I was a kid, but just never got around to taking the tests. Also I was scared off by the code requirement, and didn't bother to start even when the code requirement was dropped.

By the time I got my act together to actually sit for the tests, I had to place catch-up with my mom.

Funny, I am officially a 3rd generation operator, but we are mostly disconnected. I remember my grandfather having a radio room, but don't think I ever saw it in use. The basement was plastered with QSL cards, and I thought it was CB. My mom got her ticket about 5 years ago, not when I was a kid. I am working on my son, but he doesn't want to read the book; so it will take a while :)

Back to the OP: if you want to bat around fun theory, learn about transmission lines and impedance matching. It will help understand the problems if you ever need to wire up motors on long feeds from VFDs. The problem that your customer is describing sounds like a transmission line impedance mismatch, though it could also be an antenna balance problem putting RF current on the outside of the feedline.

73
Jon
 

mike_kilroy

Senior Member
Location
United States
Ya'll are starting something here with all the greenhorn comments! Who will beat mine? 12yrs old, 1965, novice. 12.5 yrs old advanced (took extra and passed it and 20wpm at same time at Detroit FCC field office, but at the time you had to be a ham for 2 years before you could get extra - so that had to wait a bit)... Then First Class for commercial radio repair in 1972... The challenge is out!

On the OP, the answer is simple and I am wondering why no one gave it yet: Buy a Ham Radio Antenna Tuner for the guy and resell it to him for the slight profit you deserve for solving his problem once and for all! He will have NO significant reflected "current if you want to call the high SWR that."

And since he had you run 54' 1/4 wave radial(s?) he obviously is using 80 meters, so get a low band tuner; just ask him what max power he runs so you get one rated high enough....

I would be a bit concerned over shocking swimmers though if they touch the cage while he is transmitting. You can fully light a 4' florescent bulb just holding it near an antenna with 150 watts...
 
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