IS it illegal?? Both FRS and CB bands are open....no license required!
It's the transmit power that's the regulated portion of each (5W for CB and
not sure for FRS).
If he's thinking of FRS then dump the CB idea....traffic seems to be getting
less and less all the time (just the odd trucker looking for a good place to
chow!).
"Form@C" wrote in message
news
On Sun, 18 Apr 2004 13:48:26 -0500, Andrew Kesterson wrote:
I have been looking on google and can't find anything on this subject.
I want to take a mobile CB radio, designed to run off of a 12 volt power
line in an automotive vehicle, and convert it to run on 9V, C, or D cell
batteries so I can put it in a backpack and take it with me when I go on
long hikes away from home and the like, and talk back to a base station
in
the house.
If you really must.... ;-)
Would it be as simple as connecting a bunch of batteries together in
circuit and using a resistor (or series of resistors) to lower the
current
(if too high), or using an amplifier to raise it?
You can use NiCd or NiMH cells wired in series to give the required
voltage. Both of these are 1.2v per cell, so a 12v supply would need 10
cells. The portable CB radios tend to use the AA size, but Cs or even Ds
are ok if you don't mind the extra weight and cost! Whatever you
do, *please* fit a little fuse adjacent to the battery pack - especially
if using NiMH cells as these can easily give enough current on a short
circuit to be dangerous.
Don't attempt to modify the internals of the CB at all. Just provide 12v.
You could also use a sealed lead-acid battery of course.
You will probably have a high/low power switch on the CB. Use low power
whenever possible. It will lengthen your talk time appreciably. It is also
rather unwise to use high power when you are using a little rubber aerial
a few inches from your head!
I have some basic electronics books on these subjects (basic, basic
digital, and basic communications electronics books from radio shack),
but I wanted to get some input before I went and tried to do something
and blew up my radio. :-)
Would this be possible using the methods I described? Would I need other
methods? Or would I just need to give it up and try something else?
(Also, does anyone know where I might find information about changing
the frequencies the radio runs on? If I could find a way to make it run
on the same frequencies as some smaller GMRS radios I have, that'd be
awesome... but from what I understand it would probably require changing
the entire guts of the radio... so if that's not feasible don't worry
too much about it. :-)
No - two reasons. First, its illegal. Second, it needs careful setting up
with specialised test gear just to move the frequency a little. They just
won't go into the GMRS band - and wouldn't communicate with them even
they did! If the range of a GMRS is sufficient you would be better using
one of those anyway.
Follow-ups set to alt.electronics
--
Cheers...
Mick
Gave up on viruses & trojans - moved to Linux... :-)
Nascom & Gemini info at http://www.nascom.info