Crossband Repeater in a Box

A cross band repeater unit I built for motorcycle rally and Jeep event use.
This is the basic setup before I installed the wiring. Radio on the left (KGUV8D) Low cost UPS battery in the middle. This is an 8AH battery. Right is a charge controller 20 amp unit which is way overkill for this build as the radio draws very little power.



Setup in my front yard with camo netting installed


Broken down in "travel" configuration. You can easily cut the tripod, NMO magnet mount and 1/2 wave antenna out of the pack up and use a roll up j-pole antenna then you'd just have to carry the box and solar panel.



Time lapse of setup and tear down

[ame="http://www.youtube.com/watch?v=pxOE4Vj6aKk&nohtml5=False"]Mobile Crossband Repeater setup. - YouTube[/ame]

[ame="http://www.youtube.com/watch?v=sTkYFqixwPo&nohtml5=False"]Repeater tear down. - YouTube[/ame]


This unit will be in operation at WARPED in Kernville, Ca this year.

And how is txcvr mounted to bike?

[ame="http://www.youtube.com/watch?v=yeb1PjllFAQ"]Motorcycle Ham Radio Setup on my VStrom - YouTube[/ame]

Oh yes, I saw that one a couple of weeks ago and was going to mount the same way.

I was going to mount a small whip on the end of the tail rack.

Very nicely done. Your antenna issues are likely ground plane related; every thread I've read says it's impossible to get a decent ground plane for a higher gain antenna on a M/C chassis.

I'm sure you saw this guy's page... http://www.wd6cmu.antennalaunchers.com/mm_radio.html

The antennas are spaced far enough apart that they will just clear the top box when it is installed, but they only add about an inch to the width of the bike. They are Diamond NR770HBs, 1/2-wave on 2M and 2x 5/8-wave on 440. You want a 1/2-wave design on motorcycles because they don't have enough ground plane to support other vertical configurations.

Click to expand...

cheez said:

Very nicely done. Your antenna issues are likely ground plane related; every thread I've read says it's impossible to get a decent ground plane for a higher gain antenna on a M/C chassis.

I'm sure you saw this guy's page... http://www.wd6cmu.antennalaunchers.com/mm_radio.html

Click to expand...

I don't remember seeing that before.
Thank you very much for that link info.

cheez said:

Very nicely done. Your antenna issues are likely ground plane related; every thread I've read says it's impossible to get a decent ground plane for a higher gain antenna on a M/C chassis.

I'm sure you saw this guy's page... http://www.wd6cmu.antennalaunchers.com/mm_radio.html

Click to expand...

The one that has the issues is a half wave. SSB5. Some electrical component on the bike must be emitting just the right frequency for that 1/2 to effectively jam my signal out or in. I mostly run with a 1/4 wave now which is interference free and gets me a bit better performance than the HT mounted antenna.

There's plenty of metal on a bike for a ground plane the problem is it's creates a weird radiation pattern because it's not a large flat metal surface like a car's roof would be.

Even multiple ferrite chokes couldn't solve the issue. Neither did changing out HTs to multiple different units.

Downs said:

The one that has the issues is a half wave. SSB5. Some electrical component on the bike must be emitting just the right frequency for that 1/2 to effectively jam my signal out or in. I mostly run with a 1/4 wave now which is interference free and gets me a bit better performance than the HT mounted antenna.

There's plenty of metal on a bike for a ground plane the problem is it's creates a weird radiation pattern because it's not a large flat metal surface like a car's roof would be.

Even multiple ferrite chokes couldn't solve the issue. Neither did changing out HTs to multiple different units.

Click to expand...

What kind of range are you getting.
I am not wanting a whole lot....

Not trying to hit a repeater somewhere in the distance.

The repeater I usually use is about 24 miles away from the house but I've hit it from over 50 with the HT.

Your biggest enemies are terrain and antenna height. I've made simplex contacts from a ridge line 98 miles away and on the same day had a 1 mile range tops with my riding buddy.


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