Larsen 2m 1/4 wave roof antenna

Just finished cutting and tuning the Larsen 1/4 wave VHF antenna. I did roof mount it. Some have asked about these antennas. For roof mounts I like commercial products as they usually have a secondary seal. This uses their "Super Seal" gasket in addition to the standard O-ring under the NMO mount itself.

 

...^^^... nice setup and good info on "seals"

 

Same antenna and mount I used on my 05 AC, good choice

Had a Wilson 1000 whip hard mounted as well.

 

For general repeater use, in town driving, and mountainous terrain, it is hard to beat a good old fashion 1/4 wave. So many of these companies advertise their "Super Gainer" etc. and have a bazillion coils and whirly twirlys to make the antenna look awesome, but on an analyzer and working tests they really are not good for general use. The more gain the further the signal, sure, but it goes straight out vs. up and out which kills you for hills, mountains and repeaters etc. AND they don't break off!

 

Nice, I have 2 on mine. The original one I did back in 2009 and never had any issues or water intrusion. I installed the other one just a few weeks ago. I originally had a 5/8 wave that I was trying out with a Wouxun hand held that I have setup for a dedicated APRS radio. But I switched out that antenna for a 1/4 wave.

 

? You kinda lost me on that. You're wanting a higher angle of radiation as opposed to a lower angle? Did I misread that?

 

the way I see it, 1/4 wave is better for canyons and rolling terrain as far as how the signal propagates from the antenna. And 5/8 wave for flat terrain like a desert region

 

Correct. For repeater use a higher takeoff angle is preferred which you get with 1/4 wave. I own three ham repeaters in Oregon.

 

Nice job! This is on my to do list.

K7NI

 

Thanks for the info. I haven't had a need for the higher radiation takeoff angles before, but nice to know if I do.

 

Sure. If you do mainly simplex work and need the signal to go low and long then you want more gain. So a 5/8 wave with 3db or multi wave for 5db or more.