[NLRS] Wanted: Rover antennas and and tower

[Dr. Gerald N. Johnson]

I ran many days computer analysis of stacked 144 and 432 yagis a couple 
years ago. I found practically no loss of gain (around 1 dB) on the high 
band yagi when a 1/2 wave from the low band yagi, far closer than the 
1/2 boom length often suggested.

I also found that the rear 9 elements of the K1FO design in the ARRL 
handbook gives better gain per boom length than longer commercial yagis. 
10' for 2m, 1 meter for 432, computer says 11.8, CSVHF range says 12+ 
dBd gain, two years in a row. Beamwidth is about 75 degrees at 10 dB 
down, 42 degrees at 3 dB down which makes for easier aiming than much 
longer yagis. The Msquared 144SSB is nearly 15 feet long for the same 
performance.

Article was presented at Aurora 2 years ago and published in several 
proceedings including CSVHF last year.
www.geraldj.networkiowa.com/papers/2012/HowCloseBa.pdf

Watch out for bridge and tree clearance, most yagis don't stand up to 
either well when the rover pokes them up while in motion. And many 
residential streets and public parks don't have trees trimmed back to 
the 14+ feet of main highways.

73, Jerry, K0CQ

On 5/7/2013 11:05 PM, Matt Holden wrote:
>
>
> W0ZF and I are building a grid square roving machine.
> i put a beast of a cargo rack on top of my jeep, so, were thinking big.
> We're looking for a small glen martin roof top tower and beams for 50 MHz,
> 144 MHz and 432 MHz.  got any you want to part with?
> Dave and I will be at Aurora and look forward to receiving advice from you
> experienced rovers.
> The goal is to be running the beast through South Dakota in the June VHF
> contest.
> 73 Matt K0BBC
>