[amsat-bb] Re: Which Mobile Mag Mount?

Clint Bradford clintbradford at mac.com
Wed Sep 14 22:29:17 PDT 2011

First, almost every mag mount will scratch your car - something never printed on the packaging.

Second, any "vertical" antenna for the V/U FM sats will have a transmission (and generally receive pattern) 
that is perpendicular to its mast. So, think about it: A GREAT pass of 90 degrees goes overhead - your 
vertical is valueless during the middle of that great pass.

SO ... Some are "compensating" by purchasing better antennas (i.e., more gain) and pumping out 20 or 
50 or 100W. Awful wasteful, IMHO - since we both know we're workin' these birds with a Watt or two.

Ideally - in a car - I would think that stopping and parking and getting a vertical perpendicular to the 
orbit of the satellite would give best results. I have a Larsen KG-2/70-CX-PL whose whip I can adjust about 
20 degrees off normal, and hopefully be travelling in the correct direction to work a bird or two.

But if you're going to stop and park - then just whip out your homebrew Tape Measure Beam from the trunk, 
and REALLY make some contacts!

BUT - You told me you wanted to keep moving with the familt in the car. So ...

Then maybe a Larsen mag mount - which you can purchase an extra whip. And bend - er, I mean, 
"re-form" that whip right at the base so that it is about 20" bent.

Keep extra allen keys in the glove compartment - to loosen and re-position the whip. You might look a little 
funny driving down the road with a "bent whip." But you'll be more successful with the FM birds!

Got kids who are on the 'Net already? Plan your rest stops/meal stops/bathroom breaks around the satellite 
passes! Give 'em maps ... sat pass times ... have 'em figure out approximately where they'll be at what time ... 
Sure beats having them play video games or watch TV in the back ... (grin)

Suggested items:

Larsen NMO-MM-R-BNC - a solid, round mag mount with NMO connector for an antenna. This particular 
one terminates in a BNC-MALE. They have other models terminating in other connectors. Or get one that 
terminates in the FME system, and you can then purchase adapters for SMA, BNC, PL - whatever.

Larsen NMO-2/70 BLACK - very good dual-band NMO base whip.

Larsen W270B - just the replacement whip.

HRO carries all this. Snag the Larsen Amateur Products .pdf catalog at ...


Clint, K6LCS

More information about the AMSAT-BB mailing list