How can I maintain contact with mobile person

[Lightspeed]

Some thoughts for you Steve:

The ultra low cost Pixie ii
An under £10 possible solution.

Possible because it might work if you are very lucky. This is really a last ditch fall-back transceiver for use when everything else has failed. I would not use it for vital or dependable communications:

http://3.bp.blogspot.com/_AYMN9rEwslM/TU...ematic.gif
Pixie as a simple to construct kit:
http://www.halted.com/ccp13844-enhanced-...kit240.htm

A much betterkit alternative would be:
http://www.qrpkits.com/fttut.html

You’ll also need a tuner like this:[i]
This is a must have for anyone seriously looking at emergency radio set-ups as it allows end fed wires to be tuned for resonance with the transmitter. End fed wires can be very efficient as well as being ultra low profile.[i]
http://www.qrpkits.com/sota.html


Some alternatives to consider:
This is a single radio that covers both 7 and 3.5Mhz plus two other useful ham bands. Morse code (CW) only. 4 w output
http://www.wsplc.com/acatalog/HB-1B-MKII.html#a10898

This one is capable of operating in voice mode ( SSB) on 5 frequency bands including 7Mhz. I have not used one of these but its specification and build quality looks like it’s a robust self contained package. It even comes with a lithium internal power supply
http://www.ebay.co.uk/itm/Youkits-TJ2B-M...41766d0a98