Bicycle mobile operation on 2m is attractive for a lowland flat-dweller, especially with the South Downs national park nearby! This article describes one solution to getting on the air on 2m from the saddle.
I built this antenna in February 2010 from a design on the website of John S. Allen, AA1EP:
2-meter J-Pole from bicycle safety flag
I built the antenna with Martin, G7RQD with the assistance of an MFJ antenna analyser loaned from Nigel, G3YSW. We used a cheap (99p) extendible 1.65m fishing pole and some scrap solid core mains wiring that I'd stripped out from my house. It took approximately 2 hours to construct and get the antenna tuned as the lengths and feed point are critical. In the end we got that perfect match - zero reactance and 50 ohms resistive at 145.2 MHz.
I've used it for several contacts while out bicycle mobile and it also provides increased visibility to motorists when on the roads. I've got good signal reports back when using with my hand held and it certainly beats a rubber duck. Personally, I've not mastered true mobile use as my VOX tends to be a bit sensitive to the wind so I generally stop for QSOs.