The amateur radio club to which I belong provides communications for a marathon that is run every year here in town.  As a relatively new ham, this was my first public service event.  I rode a bicycle--bicycle riders were assigned to follow the lead runners so that the race directors could keep track of the race progress.  All of the cyclists used handheld radios, including me (Yaesu VX-6r).  I was the only one using the stock rubber duck, everyone else appeared to have aftermarket whip-type antennas (~16" long).  However, there were points along the course that all of us had trouble getting into either of the two linked repeaters.  I am interested in better antenna solutions for a bicycle.  I will continue to use the handheld, probably clipped to my belt or in a handlebar bag.

The problem, as I understand it, is that bicycles do not provide a good ground plane.  Hence, I've been looking into antennas that do not require a ground plane.  

I first considered a 2 meter j-pole.  There are examples of folks online building j-poles by taping wire to fiberglass bicycle flag masts (http://www.bikexprt.com/bicycle/antennae.htm).  While this would work (or I could probably just zip tie my N9TAX j-pole to such a mast), it is really quite long--it would be nicer if it wasn't so tall (~60" total height).

The next thing I stumbled upon was a half-wave end-fed antenna, such as described here: http://www.qsl.net/n1lo/2mbike.pdf  This is more compact than the j-pole at only ~40" total height.

Any other ideas?  I think either of the ones listed above would be fun/easy to build.

You could take a BNC/SMA/PL259 connector and add a ground plane to it. But antenna height will probably help as much as adding the ground plane. Put it on the top (or build as part of) of a fiberglass whip attached to the bike.

Or add a GP-1 base station antenna to your bike
http://www.cometantenna.com/amateur-radio/base-antennas/ba-dual-band/

http://www.hamuniverse.com/w6jmf2mhtgroundplane.html

Usually 1/2 wavelength antennas work well without radials or counterpoise. Google: "2m antenna for bicycle" and you'll get a lot of information regarding this subject.
Here is a good article on Bicycle Mobile Operation with pictures.

This is actually a good subject for me as well since I plan on doing some amateur radio on horseback. I have my APRS symbol set to "horse" and I don't want to be called a liar

I can't see why the bicycle frame wouldn't provide a good ground plane for 2 meters.

A quarter wave on 2 meters is about 19".

How about a vertical dipole on one of those fiberglass flags ?  19" vertical section connected to the center conductor, 19" vertical section connected to the braid ? You could also have the bottom section that is connected to the braid just blowing in the wind if you wanted to.
A slight variation of this would be to mount a 2 meter mobile antenna on something and then have a 1/4 wave wire connected to the base. If you had one of those racks that sits horizontally over the rear tire, you could mount it there and use the rack itself as a ground plane.

^^^ This. You can even elevate it a bit with a PVC mast if you want.

Actually, pretty much any good quality mobile antenna can be run that way with excellent results, better than any rubber duckie no matter how long. But the math works out best with the 1/2 wave

I'm in for the 1/2 wave.  Back in the 90's, I had installed a short (2') CB antenna on my bike, on the aluminum rack.  Mounted a Uniden Pro510XL to the handlebars, and had a 12v 10Ah battery on the rack.  It worked fairly well, for a CB, and that was with a really odd shaped ground radial... that was shaped like a Schwinn Moab.  



I'd Just mount a 1/2 wave to a rack, run some coax where you need it, and go with that.  The 1/2 wave antenna will be miles better than anything mounted to the radio itself.  



That has given me an idea... I should mount a small mobile 2m rig to my bike.  Or maybe one of those new Jetstream 10W dual banders!



Brilliant!

Larsen 1/2 wave NMO should work well, if a bit pricey.  Google "Flower Pot Antenna" for a cheap antenna that should work well on a bike.

Hamsexy approved!

Haven't been on the computer since this morning. Gamma762 sent me a message about this thread.  I have done a lot of bike mobile.  Both HF and VHF.  I have worked bike mobile SAG at numerous events including multiple times at the Hilly Hundred.  These pictures are the system that I currently use and is the one that has worked best for me.  In the pictures I was using a VX5.  I now use a VX8GR so I can combine the VHF phone and APRS into one radio.  The radio is mounted on a RAM mount on the handlebars.  The antenna is a Larsen 1/2 wave NMO on the rack.  Half wave antennas work best because of the limited ground plane area.  I seldom use UHF on the bike. I do have a dual band antenna and can do it but I find that since I seldom use 70cm on the bike I would rather have the more flexible Larson antenna instead of one with a coil in the middle.  

I have had many of my different rigs at the BMHA forum in Dayton.  I had this setup there last year when I was speaking about working bike mobile SAG at the Hilly Hundred.  As I said above it had the VX8GR instead of the 5 in this older picture.









Antenna is mounted on an aluminum base that I made with 2 short pieces of angle.  The antenna in the picture has worked the best of the many I have tried on that NMO mount.

He asked for something that works not something to show how stupid he could be.  



 

I think I will have my bike set up as pictured again this year at Dayton.  

If you will be at Hamvention I would like to invite you to ride with the BMHA group on Saturday afternoon and attend the forum on Sunday.

And you have no sense of humor.

+1 for a half wave vertical dipole design - maybe built from coax & ziptied to a 1/4"  fiberglass rod for support. To build,  remove outer jacket for 1/4 wave distance down from the end then pull sheath down/inside out for lower element - center conductor is upper element. Go a little long on initial dimension & trim for desired sweet spot.

ETA  look up vertical bazooka for better description & formulae

Nick

Sorry,  I was just giving you shit.  I guess it didn't come out the way I meant it.





 

Back in the old days, like 1980, my friend Dave and I would ride around town on our 10-speed bikes talking with our IC-2AT handhelds.  Sometimes the factory rubber duck wasn't enough to get across our small town and I'd use my VoCom 5/8 wave telescopic antenna.  Looked just like this (not mine, but shown with the same handheld even), it's a wonder that I didn't die riding a bike and holding this in one hand while talking on it.

http://forums.qrz.com/showthread.php?368276-5-8-wavelength-2M-Whip-Antenna-for-HT-with-BNC-Base

Local guy.

Personal preference, I'd go with the half wave mobile antenna. A quarter wave would probably work as well…but if you can deal with the adde length might as well not chance the GP not being present in the bike (it should be but we all know about assuming). If you're confident it is there you may even try a 5/8 wave antenna.

I've never done bike installs. But I have done a quad install or two for some SAR friends up in Colorado. After installing the mounting brackets and NMO mounts, we ended up throwing a 1/4 wave on there to test with an antenna analyzer to see if the ground plane offered by the quad was sufficient. Saw that it was (may vary with the quad as more and more are going to hybrid, plastic utility racks) and ended up throwing 5/8 wave antennas on there.tuall

I'm actually beginning two finally get around to my own quads…but if I run anything more than UFH 1/4 wave antennas it will be UHF 5/8 wave antennas.

Couple of extra comments on KM's setup.  Antenna pictured is Larsen's wideband 1/2 wave base... a standard bandwidth model can cover the amateur band, but with the rider on the bike it moves the resonance around so the wideband coil gives you more cushion.  Second, Larsen (and some others) use tapered whips... the tapered whips are thinner at the top and will sway less than a straight whip.  The straight whips are more likely to sway enough to hit the rider.

You sure know a lot about that antenna.  Is that because you sold it to me?  I have tried other antennas but this one has been the best by far on a bike.  I have had excellent results with the HT at the Hilly Hundred.  Most say a HT won't work on that route.  They claim you need a high power rig.



 

Dude -- put that on a bike and you're going to put someone's eye out with it as you cruise along!









 

Wow, thanks to everyone for the replies, it is a lot of information.  Very helpful!

Since I am cheap, I will try building something first.  It looks like an end-fed half-wave is the general consensus.  I hadn't heard of the vertical bazooka or flower pot antennas before, maybe I'll try one of those.  I don't have anything to tune it with, but I am sure someone in my club can help me out.

If I do wind up buying something, I really like km's setup.  My rear rack is a bit different (it is all steel tubing, no flat section in the middle), but I am sure I could figure something out.  Since it was mentioned that the antenna is Larsen's wideband half-wave base, is that this one?  
NMOWB150B, Wideband, 1/2 wave, 135-174 MHz, 0/2 dBd/dBi, 51.75" 100 power rating (Watts), Black
Since it was mentioned that a rider sitting on the bike will shift the resonance, did it require tuning?

Also, if I get the inclination to have a dual-band antenna, would this Larsen antenna be a good choice?  (Or is the widebandedness of the above antenna necessary?)
NMO2/70B VHF: Center Loaded, 1/2 wave, 144-148 MHz, 3.8 dBi, 34.5", 100 power rating (Watts), Black
                 UHF: Collinear, 440-450 MHz, 5.2 dBi

that is the antenna.  The rack is a very cheap rack.  About $25.  Antenna can be found for 39 to 49.  It still isn't a real expensive setup with the mount and all if you are going to do much bike mobile.  If you are going to be at Dayton you can see my bike.  It will be at the BMHA ride and forum.  It has been there for about 5 years now.  I would stay away from a dual band antenna unless you will be using the 70cm side of the radio.  My dual band antenna is a Tram that I bought for $12 at Dayton.



 

A quick preview of a presentation I will be giving at Hamvention.  (You are special.  You get to see this first. I show it to the short bus crowd first. )

Bike mobile for events.  Ie. distance rides, races, or parades.

Equipment on bike.

>Yaesu VX-8GR.  I use this radio bacause of the built-in APRS. We use APRS tracking for many events.



>LiFePO4 battery in bag on rack. More battery life than internal radio battery.



>small first aid kit. Not for major injuries but can be helpful



>Bike tools.  Can keep your bike or others on the road.  What you carry will depend on the type of event.



>spare tube and tube patches.



>tire pump



>snacks and water. What and how much you carry will depend on the event and the availability of food and water.



>Larsen WB-vhf NMO antenna.  I use this antenna because I have found that UHF is not used at many events.







Handlebar setup with RAM mount.





Rack with supply bag and antenna.





Larsen WB-VHF antenna and Tram dual band antenna that I picked up last year at Dayton for $12 in case I ever need dual band.

Have tried the Tram and much prefer the Larsen unless 440 is required.





Quick preview without all the explanation that goes with the presentation.  This is the result of about 10 years of bike mobile SAG at events.

What do you have the HT mounted to the bike with?

Topeak bar extender. http://www.amazon.com/Topeak-60001001-The-Bar-Extender/dp/B000FIAVN8

RAM radio mount on the bar extender.

RAM mount is the HOL-BC1U  http://www.rammount.com/part/RAM-HOL-BC1U

The bar mount that I have is no longer available.  You will have to pick on of the others.  With one of those you may not need the Topeak bar extender.  I do use a velcro strap around the radio.  I don't know that the belt clip wouldn't be secure enough but I just like the extra security with an expensive radio.





 

Thanks!

The XYL and I are looking at getting a pair of recumbent trikes.  She's working her license (and finally taking it seriously) and I would like to have comes while riding.