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[GM1ZVJ]

HI THERE,
         anyone help me with the following questions ,to help me with my new antenna systmn.
         
          1/whats the minimum distance i should mount my 10 ele 2mtr beam above my 5ele 6mtr beam ?.
           2/ any ideas on how to keep birds from perching on the antennas ?    ( have tried using a plastic owl with no success !!.
            3/ have heard of stations coatting there antennas with a varnish ? for extra weatherproofing.
 any ideas??.
                                   thank you.
                                             JOHN GM1ZVJ.

[K5MA]

I have an M-Squared 6M7 (7-el 6M yagi - approx 28' boom) mounted approximately 2 1/2 feet below the bottom of two stacked M-Squared 5 wavelength yagi's.  The 6M7 is at 82 feet above ground on a Rohn 25G tower.  The mast protrudes about 17 1/2 feet from the top of the tower, and the 6M7 is mounted just above the top thrust bearing.

I have observed a noticeable decrease in performance of the 6M beam since I moved it to the new tower configuration.  Previously, it was on another tower at about 90 feet elevation, and about 10 feet above a 5-el Hy-Gain 20 meter monobander.  The major difference between these situations is that the 6M beam is very close to the long boom 2M beam.  I 'feel' that it just doesn't get out like it used to when it was mounted much further away from a large antenna.  This is only a feeling, not confirmed by A-B comparison testing.  I have run SWR curves on the 6M7 in its present configuration with an MFJ-259B, and I find it has many peaks and valleys in the 50-54 Mhz range, although its pretty flat around 50.1-50.2 Mhz.

I can't tell any difference in the performance of the 2M stack with the 6M beam in close proximity to the bottom 2M yagi.  I had the 2M system up for a few months before putting the 6M beam up, and didn't observe any 2M performance changes after the 6M beam was in position.  The 2M stack has a vertical separation of 14' 3".  

I would be interested in hearing from others that may have close mounted 6M/2M yagi combinations.

Jan, K5MA
West Falmouth, MA

[WA0TML]

I had my 6 meter antenna (5 element) at approximately 6 meters up on a mast with rotator and mounted the 11 element 2 meter antenna approximately 2 meters above the 6 meter antenna.  I did not experence any problems and was able to work stations all over the East Coast and into the Caribbean Ocean regularily from Colorado.  On 2 meters I worked the neighboring states regularly.

A rule of thumb I have used successfully is 1) as far apart as possible 2) 1/2 the boom length of the antennas - usually the shortest boom.  Hope this helps.