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Thread: Weak Signal Due to Antenna Location?

  1. #1

    Default Weak Signal Due to Antenna Location?

    Hi all, hope this is the right spot for this.

    I live on the 10th floor of a 30 floor high-rise building which is all concrete and I'm sure lots of rebar in it. So a little more than 100 ft. up. I'm located in the center of the building which has three more units to each side of me. I have a monopole which I mount over the side like a fishing rod w/ a length of about 16'. Its made by Chameleon Antenna. I receive 80-10 just fine. Here's my configuration, all cable is RG-8X and gear is Elecraft.

    transceiver --> 3 ft. cable --> amp --> 1 ft. cable --> tuner --> 50 ft. cable --> antenna

    I think my problem is just the environment I'm in and probably nothing I can do about it but I wanted to confirm this with some of you guys. By environment, I mean the building, its materials (concrete and rebar), another high-rise directly in front of me, and the position of the antenna (horizontal) which is the best I've been able to do. I've tried many antennas in the past, dipoles and such, but it seems the further I "fish" out and away from the building, the better the signals.

    My real problem is that my signals are unreadable and very weak for anyone just a few hours or more driving distance from where I live, and thats using the amp. No one can make me out. They know someone is trying to contact, but the readability isn't there and the signal is too faint. I feel like my signal is either going straight down into the ground, or straight up into the sky. I did a scan using a RigExpert AA-54 and here are my SWR readings on the antenna.

    1.900 kHz SWR: 4.7
    3.900 kHz SWR: 2.9
    7.200 kHz SWR: 3.9
    14.300 kHz SWR: 1.40
    29.000 kHz SWR: 1.7

    UHF/VHF works fine as I can reach local repeaters, but HF … I feel like I'm just running out of options.

    Any help much appreciated.

  2. #2
    Super Moderator 5B4AJB's Avatar
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    First of all, your 16' antenna isn't going to do much below, say, 21MHz. 14MHz seems to be approaching it's useful limit.
    Second consideration is RG-8, not the best kind of coax, even for H.F. It may be worth investing in some RG213 (I know it's a pain to handle).
    Third thing to consider is background noise, even with the best equipment you may still be unable to operate from that location.

    Noise comes in many forms, flourescent lighting, switch-mode power supplies, even the mains Voltage may have noise on it.
    You can try a mains filter or an antenna noise bridge, but even together I think you'll still have problems.

  3. #3

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    Today I spent some risky time w/ the antenna during day-light hours (non-stealth mode), trying to tune the radial, and took some photos of the current setup. These might help in understanding what I've go so far.

    https://www.dropbox.com/sc/7z68rexs71twj2f/vsILGA8beJ

    I ended up removing the counterpoise from the base of the antenna which I had strung across the top of the railing. Turns out my SWR reading were better without having any radial at all. But the background noise greatly increased. These are mostly down from what I had before.

    1.900 kHz SWR: 4.8
    3.900 kHz SWR: 1.7
    7.200 kHz SWR: 2.7
    14.300 kHz SWR: 2.5
    29.000 kHz SWR: 1.7

    Well, at least its useful to listen to, but thats about it.

  4. #4
    Super Moderator 5B4AJB's Avatar
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    You could try to get the base of the whip away from the railings a bit. Use something non-conductive (black plastic pipe has carbon in it so it's partially conductive) a plastic pipe with wood inside should be strong enough.
    Also, your earthplane coming off to the left is very close to the railings, try letting it dangle, or if not possible, snake it around on the balcony floor.

    I've got a feeling your radiated R.F. is hitting the railings...

  5. #5

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    Quote Originally Posted by 5B4AJB View Post
    I've got a feeling your radiated R.F. is hitting the railings...
    Isn't that a good thing? I mean, isn't that the purpose of the radials, to make a plane so that the radiated RF would be a bit more directional and not come back into the units where and, if I didn't have ferrite beads on the cable, the RF would couple into the power lines and make certain sockets trip.

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