I've operated HF CW bicycle mobile occasionally for several years, but
never had quite figured out a good place for the key. I could send OK,
but my hand would quickly tire since I have to simultaneously grip the
handlebars and send the code; my hand was stretched out uncomfortably.
Recently I tried a new position for the key and it works the best of all
that I've tried so far. Pictured below is a detail of the key.
-Key details-
The key is made from double sided circuit board material about 1.5 by .5
inches (4 by 1.5 cm) with brass shim stock soldered to both sides (for the dot and dash
switches) and appropriate cuts made on the copper cladding.
The shim stock is bent ever-so-slightly out so that it doesn't short
circuit unless the shim stock is depressed against the circuit board. The
switch is exteremely sensitive; in fact strong winds were keying it so I
had to bend the shim stock out a little more! I disassembled the Grip
Shift SRT400-32 front changer and cut a groove in it internally which the
circuit board is jammed into.
The key is positioned such that I don't accidently bump it while shifting,
but can still key while gripping onto the shifter and handlebars. I made
the key as narrow as possible to minimize the difference between the hand
position used while sending code and my normal grip on the handlebar. The
shifter is rotated on the handlebars so that the key is closest to where
the thumb and index finger are if those fingers are not gripping the bar.
-Radio details-
Pictured is a Mizuho MX-14S modified with a 15W amplifier installed where
the batteries were originally. This is a SSB/CW 20m handy-talky. I have
it mounted to the handlebar stem with cable ties. I cut up
an old inner tube and placed about four layers of that between the stem
and the radio for shock absorption. On the bottom of the stem I have
strapped a homebrew electronic memory keyer.
I don't use an external speaker or headphones presently. I have used a
boom-speaker mike in the past with success, but I don't like the wire
flopping around.
For power, I'm using 11 4400 mA-Hr NiCd batteries in an aluminum box
strapped to a rear rack. The rack has a flat piece of metal
on the top and I have drilled a hole and put an antenna mount there. I'm
using a commerically made center loaded fiberglass whip antenna (about
seven feet long). The battery pack is over-kill, but I already had it
laying around (I use it for powering a 20W headlight normally). Cable
ties attach the wires to the bike frame.
-Results-
The sunspots are coming back! I worked ES1WN (Estonia) on September 4, 1998, shortly after
trying out this key and got a signal report of RST 569. That's the first
DX I've contacted bicycle mobile in 3.5 years!
The bad part of this setup is it's not at all waterproof, so I have to
examine the forecast carefully or I'll wind up having to cut all the cable
ties holding the radio and keyer to the stem when the raindrops start
falling and jam the equipment into a pocket. Also, water gets between the
circuit board copper and the brass shim stock and keys the keyer. I also
occasionally have problems with the switch contacts getting too close
after some use, and keying by itself. I just stop briefly and bend the
shim stock out again if that happens. I'll try some thicker shim stock
on the next incarnation of the key.
I'm able to send fairly good code even on moderately bumpy gravel roads
and yet have a safe and comfortable grip on the handlebars with my hand
close to the brake lever. Only my thumb and index finger are in a
different position than normal, and they do not tire as quickly as other
spots I've tried to mount a key. Now I only wish I was coordinated enough
to actually shift the rear derailleur and send code at the same time. I
always send extra dots or dashes with the other hand if I try!
Here's another CW bicycle mobile page by
VE3JC. It has some good photographs.
Back to Russell's home page
Back to KB8U's Bicycle Mobile page