December 2015. My wife and I do our 'big shop' on a Saturday morning. As I can't abide crowded supermarkets I take the opportunity to go for a health-giving walk around town while she braves Tesco. I don't have a mobile phone so often one of us will end up waiting for the other at the car. A pair of 446 MHz walkie-talkies seemed to be the answer.
A quick browse around Amazon resulted in a couple of Motorola T41 radios being delivered a few days later. They are chunky little sets that fit easily into a pocket and come with a detachable belt clip. Our next shopping trip proved that they work well across open space but soon reach the end of their meagre range in more built-up areas. I was disappointed that a 500mW transceiver could have such a poor range. Perhaps my vast(!) knowledge of radio and electronics could improve things?
I gritted my teeth and took one of them to bits, marvelling at the solid construction and relatively easy access to the innards. The antenna is a short helical 'spring' encased in a plastic stub at the top of the case. This was probably the cause of the less than optimum performance.
On with the iron! I desoldered the spring and replaced it with a proper quarter-wave whip made from thick-ish hookup wire, making a suitable hole in the end of the plastic stub to allow the wire to pass through.
Above you can see the modification. On the left is the unmodified one and on the right the modded one. Between them is the 'spring' antenna which I removed.
Generating a local low power signal on 446.006 MHz, I compared the reception on the two radios. WOW what a difference! Where the un-modded one could hear nothing (squelch closed), the modified one was receiving a clear signal. So far with just one radio modified the range has increased by about 50 percent. I plan to mod the other one soon.
And the very next day....both units now have the antenna mod and the range is easily double the 'out of the box' condition. Another success!