[NLRS] 432 sprint and antenna stacking question

[Lloyd - N9LB]

Hello Mary,

After running high power ( 100w + ) I have burned out multiple pre-amps and
front ends from cross-talk between different VHF and UHF antennas that share
the same mast pipe.
I did space each Yagi at least 1/2 boom length or 1 to 2 wavelengths.

For the 432 sprint, I suggest that you just disconnect the other bands.

I am still working on switching systems for the multi-band contests to
simultaneously protect all the pre-amps and front ends from burn-out.

73

Lloyd - N9LB

-----Original Message-----
From: nlrs-bounces at mailman.qth.net [mailto:nlrs-bounces at mailman.qth.net] On
Behalf Of Mary Brown
Sent: Friday, April 16, 2021 4:30 PM
To: 'NLRS' <nlrs at mailman.qth.net>
Subject: [NLRS] 432 sprint and antenna stacking question

I will be on for the sprint from en24gp.

And question on stacking. I need to put 222, 432, and 23cm on one tower.

Antenna and half stacking distance

222-10ez 3' 3" half stacking distance

432-9wl 3' half stacking distance

23cm35x4 on an H frame 1' 2 1/2" half stacking distance

Thoughts were 222 on the bottom 2' above the tower

Then 23cm35's 4'5" above that

Then the 432 antenna 4'2" above those

According to DX Engineering mast load this will survive 120mph. 

Thoughts? Going to be running power on 432 with 750 watts and 23cm with 550
watts,  so interactions? Preamp issues from the RF fields? Preamps will be
below tower top so it will just be whatever the antenna picks up from the
other bands.

Would love to space this more but this is going on a bracketed Rohn 25 on
the side of the house. right at max wind load. 

Mary
W0AAT

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