best setup for vehicle to base communication seperated by 100 to 500 miles?
In message , Geoffrey S.
Mendelson writes
Ian Jackson wrote:
Agreed. Unless there are any hills in the way, legal 27MHz CB should get
you a reliable 5 to 10 miles and, in the USA, I believe is a lot more
popular than elsewhere, and you could well be within range of other CB
users.
From what I have read it is very popular in the EU which has far less
limitations on what you can do with it. There seems to be no practical
limitation on equipment and power, I often see articles about people
using 100 watt ham rigs, transmitting FM and packet data.
Not legally! In the UK, CB is limited to 4W of FM. Most other European
countries are very similar, although some do also allow SSB (and maybe
even AM?).
However, that's almost irrelevant, a 5 watt rig, even a 1970' handheld
with channels 9,14 and 19 will do, a 40 channel ssb rig would almost be
too much.
A handheld on a whip antenna might get you 20 miles but, more likely, 2.
To keep it almost on topic, if you were to buy a long whip antenna, fold it
over, (run it horizontaly), and connect it to an autotuner, you could use it
for CB and NVIS ham communication.
NVIS is an interesting mode of communication, it uses vertical skywaves to
get wider range local communication from HF radio.
I don't think that you get much NVIS on the higher HF amateur bands.
However, you certainly do on 80m, where (at least in the UK) most
horizontal antennas are rarely much higher than 30' or 40'. The RF goes
straight up, and (if there's anything up there to reflect it back)
straight down again. In summer daytime, the RF tends to get absorbed by
the low-level D-layer (rather than reflected), so ranges are short, and
signal levels poor. This disperses at night, and the much-higher F-layer
allows a longer-range 'bounce' - even for signals with high-angle
radiation. Most really long distance stuff is via vertical antennas,
which are notoriously poor for relatively short-distance working (beyond
groundwave range). However, above around 5 or 6MHz, high-angle signals
tend to go straight through the ionosphere, and are lost for ever.
It may all be a moot point anyway. If you join a club they will probably tell
you what equipment you need. They probably standardized on something readily
available without a license such as CB's, FRS or GMRS, or possibly if they
thought no one would notice VHF marine radios (which are illegal to use
on land, but required for almost anything that floats).
I don't want to be a 'misery-guts', but I would be a bit circumspect
about the idea of 'getting into amateur radio' because you want to be
able talk to the folks back home when you are on holiday. If you have no
previous experience of the characteristics of the amateur bands,
equipment, antennas etc, it's highly unlikely that you will be very
successful. To avoid disappointment, it might be best to stick to
tried-and-tested technology. On the other hand, why not simply forget
about the folks at home, enjoy your holiday, and take up amateur radio
when you get back!
--
Ian
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