Above Ground Pool Near Antenna...Performance?

Discussion in 'Ham Radio Discussions' started by KG0BA, Jun 30, 2020.

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  1. KG0BA

    KG0BA Ham Member QRZ Page

    I have a 24' round above ground pool within about 15 feet of my Hustler 6-BTV antenna. It has coil traps for 10 meters, 15 meters, 20 meters, 30 meters, a tube section (no trap) for 40 meters, there are varying lengths lengths of tube between the traps, and tip rod ends are at the top section of the antenna for 75/80 meters. I do have the antenna grounded to a copper ground rod driven several feet into the ground.

    Over the years, a 24' round above ground swimming pool was installed within about 15' of the antenna. I sometimes wonder whether this might have an effect upon my antenna's performance. Can anyone advise if the pool would be a detriment to decent performance being that close to the antenna? Should I move the antenna? If so, how far away from the pool?
  2. KA4DPO

    KA4DPO Platinum Subscriber Platinum Subscriber QRZ Page

    If you really want to improve the performance of the Hustler, put at least 8 to 12, 32 foot radials at the base of the antenna. Chances are the pool has little to no effect on the antenna.

    Even better performance can be had by raising the antenna 25 to 30 feet above ground, and making a ground plane.
    N1VAU, K4AGO, K0UO and 1 other person like this.
  3. AG6QR

    AG6QR Premium Subscriber QRZ Page

    Fill the pool with saltwater, and it may help!

    A typical chlorinated freshwater pool won't hurt performance, but probably isn't conductive enough to help very much.
    K4AGO, KA4DPO and K6CLS like this.
  4. N1YR

    N1YR Ham Member QRZ Page

    Is the pool liner supported by metal walls? The walls may have more effect on the antenna pattern than all the water.
    K0UO, KA4DPO, WA9SVD and 1 other person like this.
  5. KG0BA

    KG0BA Ham Member QRZ Page

    The Hustler Model 6-BTV I have, which I erected in 2001, initially made some contacts via HF on a Yaesu FT-847 Transceiver. The log book shows I made contacts on the 10 meter, 20 meter, and the 75/80 meter bands from my QTH near St. Louis , Missouri, all the way to contacts in Ireland on 20 meters, in Wales, England, and Hawaii, South Carolina, Maine, and even Russia and Italy on 20 meters.

    But, eventually, with other extensive travel obligations for business, family obligations, etc... the rig, antenna, etc,,,sat idle for almost 20 years. During that time, my wife had a 24'x 48" tall round above ground pool installed within about 10' of the 6-BTV antenna, and because we are in a rural area, we had a satellite internet dish from HughesNet installed, and it is installed within about three feet of the Hustler 6-BTV antenna, pointed away from the 6-BTV into the Southwestern sky. There is also a buried septic tank within about 10' of the 6-BTV.

    I tried getting on air yesterday,and really only received static. I'm thinking that with all these additions, plus the amount of time that's elapsed since I last used the antenna, that these things may have taken their toll on the antenna's performance, to the extent that there may have been degradation caused by the obstacles (pool, septic tank, and satellite dish), and just the potential physical deterioration of connection points, coils, etc...over twenty years.

    The sides of the pool are aluminum...Attached is a photo of the setup. In addition to the pool being close by, there is also a Hughsnet satellite dish within 3 feet of the Hustler 6-BTV antenna, which seems like it could be an issue. I plan to remove the satellite dish altogether, since we now have cable for internet. There is also a septic tank buried underground within about ten feet of the Hustler 6-BTV antenna.

    The coax is routed from the rig in my basement office through PVC to the 6-BTV antenna, through the same PVC that the internet satellite dish is also fed. I do have homemade baluns on the coax cable at the rig, and even one at the antenna. I'm not sure the baluns at each end of the coax was necessary, since the cables are all shielded for both the amateur radio, as well as the dish cables. But, I did it just in case having the two cables in the PVC would cause any kind of coupling effect. The dish cables are virtually dead now, totally unpowered, since we no longer use the satellite for the internet.

    I did not use ground plane wiring, but instead I drove a 1/2" round copper ground rod into the ground a few feet deep, and that's the extent of the ground plane that I was able to establish when I first installed the Hustler 6-BTV. It was making world-wide contacts back in 2001 using that ground plane installation method, and while I think I would have benefited greatly from a proper ground plane, with multiple ground wires emanating from the mount, I wasn't in a position to bury them sufficiently to achieve grounds maintenance around the antenna, so I opted for the copper ground rod instead.

    The Shack is in my basement office, ground level, about 40 feet from the rig to the Hustler 6-BTV antenna, and the cabling is running within PVC underground between the rig and the Hustler 6-BTV antenna. I have attached a photo of the antenna, it's proximity to the pool, the satellite dish, and the septic tank is off to the right and in front of the satellite dish.

    Yesterday afternoon, when I was testing the radio/antenna, the SWR was around 3:1 on 20 meters on the SWR meter, which suggested to me that there may be some integrity issues with respect to how the antenna is performing after all these years, or perhaps it's just the obstacles around the antenna, and/or perhaps there has been electrical degradation of the antenna components, as well as the effect of obstacles in close proximity to the antenna that's causing the 3:1 ratio on the SWR meter. I don't know, maybe 3:1 is ok? Please advise...

    I would like to be able to test the integrity of the antenna system using just a multimeter, just to ascertain if there are various parts on the antenna that require maintenance or replacement.

    1. Can I test the antenna just by using a multimeter on the connection points, at the feed point to the antenna, at the coils, etc...If so, can you advise which connection points, how to test the coils, which values I should see at these test points, and any other advice you can provide that will help me establish that at least the physical/electrical integrity of the 6-BTV is acceptable. I'm not sure how to proceed, or which values I should see at the connection points, and at each of the coils.

    2. Then, due to these other obstacles, the above ground pool, the septic tank, and the satellite internet dish, should I move the antenna, and if so, how far away from these obstacles for optimum performance. I intend to remove the Satellite dish, and the cabling to it altogether anyway, since we now have cable internet, and no longer use the internet satellite. The pool and septic tank though, are another matter. So, moving the antenna is my only recourse with respect to my needing to decouple the antenna from the pool and septic tank, if you think the pool and/or septic tank are degrading antenna performance.

    3. Do you think I even needed the baluns in the cable circuit at each end to isolate the cables running concurrently in the PVC from the shack to the antenna and satellite dish, since they both had braided shielding?

    4. Is there any other ground plane method I can use that will establish a superior, excellently performing ground plane for the antenna without having to run lengthy wires out away from the mount of the antenna? That method is a lot of work, and a nightmare for grounds maintenance around the antenna. Would a piece of buried steel grating be good and effective, and if so, how large a piece, etc...

    Attached Files:

    Last edited: Jun 30, 2020
  6. W4NNF

    W4NNF XML Subscriber QRZ Page

    I would move the antenna, but only in the interest of putting in more radials. As DPO says, it's unlikely the pool is affecting your performance per se. But if it is preventing you from laying out radials in that direction, you need to move it. 32 laid out radially around the antenna base is the way to go. :)
    WA8FOZ likes this.
  7. KP4SX

    KP4SX Premium Subscriber QRZ Page

    The antenna shouldn't bother the pool at all.
    WA1GXC and K0UO like this.
  8. W3WN

    W3WN Premium Subscriber QRZ Page

    Sounds more likely that over the years, something has happened to one or more of the traps in the vertical. I'd also check the feedline; again, after 20 years, it might be showing it's age.

    It certainly couldn't hurt, as well, to dismantle the antenna and clean all of the aluminum tubes, especially where the section meet up, to ensure that you've still got a good electrical connection. That's assuming that the aluminum hasn't 'welded' itself together over time.
    WN1MB, W4NNF and WZ7U like this.
  9. N1YR

    N1YR Ham Member QRZ Page

    Transmitting is hard, receiving is easy with regard to using an untuned antenna. If all you hear is static after years of disuse, I would first check for water in the transmission line or corroded connections, and work from there.

    If all you have is a multi-meter, and don't have or can't borrow an analyzer, I don't know if that model antenna should show open across the feed point (infinite ohms), or shorted (zero ohms) across a feed coil. But I would think that it should not measure anywhere in between.

    But you should show zero ohms, or close to it, section to section and connections from sections to the coils where there is no capacitor in series. Scratch the meter probes through the oxidation to get true readings from the metal underneath.

    If you can get an analyzer, check the antenna at the feed point, but know that standing next to the antenna will throw off the reading. Use a length of good coax to get away from the element.

    Looking at the photo, my educated guess is that the mast for the satellite dish will probably detune the antenna resonance by a certain percentage, but the pool would not be a major factor.

    I would take W3WN's suggestion, and take the antenna apart, clean it up, and reassemble. Measure and record the adjusted section lengths before taking it apart. Mark it, too, but cleaning up the aluminum may erase your marks, so have a back-up. Use No-ox aluminum wire treatment from the electrical section of your hardware store inside the joints when re-assembling it to prevent new corrosion.

    If you have to retune the antenna, the procedure is to tune the bottom section first for the highest frequency band and shortest wavelength. Then move up section by section one at a time, going down in frequency band and up in length as you tune the antenna. Tune the top section on the lowest frequency band last.

    Disclaimer: I have never owned an antenna with traps, but over the years have read many hams reporting servicing their traps every few years. I have led our group in tuning the three-band trapped vertical at the new county EOC to its new surroundings.
    WZ7U likes this.
  10. AE1N

    AE1N Ham Member QRZ Page

    Mount the vertical with the bottom just above the water level above the pool. Run radials across the pool and down to 8 round rods on the ground at radial ends. Drop two 50 pound bags of rock salt into the pool. Stir thoroughly. Feed with a good tuner ... VOILA you are on all 11 bands (6m-160m).
    P.S. Kids swim in bathtub upstairs!
    ---Layne AE1N

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