Antenna

[gsh82962]

Has anybody ran a Maco 5/8 ground plane above a three or four element beam flat side both being aluminum I want to know if there is reflection problems and how high the Maco needs to be above the beam

[MDYoungblood]

You wouldn’t be able to use the 4 ground plane elements as it would detune the beam. You might be able to use the vertical but it will take some trail and error tuning as the beam wouldn’t be in the proximity of where the ground plane was. I have seen op’s use an Antron or Solarcon above a horizontal beam.

3’s

Greg

[The DB]

MDYoungblood is right. It would be best to choose an antenna that doesn't come with or require radials. If you want to use radials, you would need to get them out of the near field of the yagi, which would require about two wavelengths (or 72 or so feet) or more.

On the other hand, if you have a vertical that doesn't have any radials, you can get away with a few feet. Four or five would be enough.

If you want to run that Maco without the radials, you will need to do some major tuning, the radials are a significant part of the matching circuit, and the existing circuit simply won't work as it does without them.


The DB

[Eman]

Just mount the Maco right on the mast coming up through the beam mounting plate and above the beam about the same 4" or so it would be above it's own radials. It will see the beam as a counterpoise / ground plane.

[9RC69]

I have just set up my Sirio 4-element beam with a Sirio 827 5/8 wave vertical. I removed all radials except for two and bent them down slightly and attached them to the main boom with hose clamps. This gives the proper electrical characteristics and also gives extra support to the main boom of the beam. Both antennas tune perfectly.

[MDYoungblood]

Sounds like a good setup. I believe the 827 is capacitive tuned so it could be installed without the radials, the elements on the beam is a plus.

3’s

Greg