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LDG RT-100 Tuner in Phoenix Heat

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KJ7CWQ, May 30, 2020.

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  1. KJ7CWQ

    KJ7CWQ Ham Member QRZ Page

    I am setting up my first HF rig in a HOA community and have decided to install a flagpole antenna. With that I have to install a antenna tuner at the base of the pole. Being in the Phoenix area we see around 100 days annually with temps over 100 degrees (and many over 110 degrees). In the sun temps can easily hit 140 degrees.

    The RT-100 antenna tuner I am looking at has an operating max temp of 110 degrees. I contacted LDG and they said they never thought much about extreme heat environments and they don’t recommend their product. I looked at SGC tuners as well and they specifically state not to install in direct sunlight. Plus their tuner is much larger.

    I like the LGD tuner due to its small size and can easily hide it with a few cactus.

    What do other HAMs do with their antenna tuners in extreme temperatures. I have to think there are others who have worked around this situation.

    Thanks for your input.

    Roy
     
  2. KJ7CWQ

    KJ7CWQ Ham Member QRZ Page

    Oops, just saw I posted this in the wrong forum. Would the moderator please move this to the Antenna Forum.

    Thanks,

    Roy
     
  3. KJ7CWQ

    KJ7CWQ Ham Member QRZ Page

    I am setting up my first HF rig in a HOA community and have decided to install a flagpole antenna. With that I have to install a antenna tuner at the base of the pole. Being in the Phoenix area we see around 100 days annually with temps over 100 degrees (and many over 110 degrees). In the sun temps can easily hit 140 degrees.

    The RT-100 antenna tuner I am looking at has an operating max temp of 110 degrees. I contacted LDG and they said they never thought much about extreme heat environments and they don’t recommend their product. I looked at SGC tuners as well and they specifically state not to install in direct sunlight. Plus their tuner is much larger.

    I like the LGD tuner due to its small size and can easily hide it with a few cactus.

    What do other HAMs do with their antenna tuners in extreme temperatures. I have to think there are others who have worked around this situation.

    Thanks for your input.

    Roy
     
  4. KJ7CWQ

    KJ7CWQ Ham Member QRZ Page

    This thread can be deleted as I recreated it in the antenna forum.
    Roy
     
  5. WA7ARK

    WA7ARK Ham Member QRZ Page

    I live near Prescott, AZ. Being at 4200ft msl, our summer temperatures are a bit more moderate than PHX.

    I am using the MFJ-998RT. It is mounted directly below the steel roof of a metal building, so it sees ~100deg F (heat rises) on the hottest days. No problems...

    I would bury the tuner in a sprinkler box with an insulated lid. The earth temperatures at 1 to 1.5ft deep are likely to be much lower than the air temperature....

    Do an experiment. Find an existing sprinkler box with irrigation valves in it. Stick a remote-reading electronic thermometer into the box, replace the lid, and watch the temperature for a day or two... Cut a piece of foam building insulation (~R3 to R5) and set it over the irrigation box lid, and measure again. I'm guessing that the temp in the box will be closer to 80deg F than 100degF...

    A lid-less inverted plastic picnic cooler with the open end facing down, sitting on the dirt surface may do it. The cooler insulation in all directions toward the air, with no insulation downward toward the earth means that the air inside of the cooler will assume the earth temperature; not the outside air temperature...
     
    Last edited: May 30, 2020
    AF7IN, WB5YUZ, AK5B and 2 others like this.
  6. KQ0J

    KQ0J XML Subscriber QRZ Page

    I had a RT-600 in Nebraska in temps up to 105 in the sun and here in Florida, but here we don't get much above 94-95. No problems but I like the underground suggestion by WA7ARK. Here I would worry
    about water underground. I switched to the MFJ-998rt and I have it in the shade up under the roof overhang now. I wonder if being in the shade and
    a small 12V fan powered by the Bias-T would help
     
  7. WA7ARK

    WA7ARK Ham Member QRZ Page

    The fan would help if the source of the heat was inside the tuner, but here it is Phoenix heating the tuner instead of the other way around...;)
     
    WB5YUZ likes this.
  8. KJ7CWQ

    KJ7CWQ Ham Member QRZ Page

    Thanks for the suggestions. I did try building a box insulated with 1” of styrofoam. Outside the box the surface temp was 145 degrees and inside it was the same after 45 minutes. The AZ sun is pretty powerful in the afternoon.

    I like the idea of putting it underground, and that might work. Keep in mind our ground temps are pretty high too. In the summer our city water supply comes out of the tap at 90 degrees.

    With all that said, I may ditch the flagpole antenna plan. I found a lot of disturbing information about Greyline Performance who makes the antenna.

    Roy

    Roy
     
  9. AF7ON

    AF7ON Ham Member QRZ Page

    I'm in Tucson and use an Icom AH-4 tuner with a vertical. It's a light shade of grey and has never malfunctioned in the heat here (106 the other day!) I think the secret is to keep it shaded - boxes in the sun can rise to much higher temperatures, particularly if they are darker colors. I also like the idea of burying it - soil temperatures are typically more moderate than air temperatures.

    My 43' vertical is supported by a fiberglass Spiderpole and works well. A flagpole or multiband vertical is not a bad compromise. Greyline Performance have reportedly built quite decent antennas but have an abysmal recent record of not delivering. Check out Zerofive antennas - just as good as Greyline but they actually deliver!

    Mike
    AF7ON
     
    AK5B likes this.
  10. N5YPJ

    N5YPJ QRZ Moderator QRZ Page

    Del Rio, TX tap water temps go up in the summer also but it is due to the sun heating the above ground storage tanks not so much the ground temperature though the ground does get warm.
     
    WB5YUZ and AK5B like this.

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