Monday, November 28th, 2011

    Surfing the radio waves
    ~~~~~~~~~~~~~~~~~~~~~~~

Hello again. Three months is quite a long time and I must appologize,
that I did not publish a single post on my gopherlog in such a long
time. During last few weeks I focused myself on my another hobby.
Depressed with trends in modern IT industry, I have begun
experimenting with radio. 

=== Shortwave listening  ===
For couple of years I do time from time listen to shortwave radio
stations from the whole world. At the moment I have only cheap pocket
shortwave radio from Roadstar, but I already have received stations
from all Europe (from Britain to Moscow, from Spain to Poland), Asia
(Iran, China) and Africa (Botswana, Nigeria, Maroco). Shortwaves
propagate in mysterious ways and finding new interresting stations is
just matter of time, weather and patience. There is nothing like
finding new station in the sounds of AM chirps and squeaks. 

Next step will be buying some receiver able to receive ranges from 30kHz
up with AM/FM/SSB. Shortwave band contains much more than just simple
spoken word stations. With proper equipment one can receive weather
forecasts via meteofax, slow scan TV pictures and other interresting
stuff. I'm all for it.

=== VHF/UHF listening ===
Recently I bought dualband VHF/UHF transciever from China. I use it
for communication on PMR446 band and shared VHF/UHF frequencies (more
bellow), but these frequencies are just small part of the scale.
Although without proper license I cannot transmit, I can still listen
on 2m and 70cm HAM bands, professional bands etc. And I do. There is
meteo-HAM-ring every morning, meteo and watter status reports from
sailing stations on our biggest rivers Labe and Vltava, daily
briefings from mountain rescue in Krkonose mountains, there is simply
a lot to listen to.

=== PMR446, CB and shared frequencies === 
Citizen Band and Personal Mobile Radio are in Europe (aside from
shared frequencies in VHF and UHF bands, most of which use local
companies on building constructions, in shops, parking places etc.)
the only ways of radio communication not requiring license. It is fun
to listen to HAM communication on licensed bands, but it is more fun
to actually be part of communication. Both bands have their advantages
and disadvantages. 

PMR446 works on frequency of 446MHz and the maximum allowed transmitting
power is 0.5W. Transciever must be handheld device with non-removable
antenna. This limits usage only to short-distance communication, cca 1km
in the city area. But you can make long distance transmissions as well.
If you are on place with higher altitude and have direct visibility to
the other person, you can make 100 or 200km distant calls. My actual top
is about 100km.

CB works on frequency of 27MHz, maximum allowed transmitting power is 4
watts. There are no limitations on transciever, you can use mobile,
portable or desktop devices with internal or external antenna. This
makes CB theoreticaly better than PMR446, but in most cases the opposite
is true. You have to have a good antenna. One half of wavelength is the
best, but that is 5.5 meters and you really can't put such antenna in
small flat. You can't do much during the day, because band is full of
transmissions from russian and spanish speaking countries, where
operators do not respect power limitations and use 100W or more to
transmit. 

.....
That's it. That's why I do not sit at my computer as much as I used to. 
I do the silly walks with 150cm long antenna in minus 5 degrees
(Celsius) to make a new transmission. I go to sleep in the late morning
hours, because shortwaves are better during the night. I make trips to
nearby hills with couple of transcievers and antennas in my bag. I study
webpages and books related to radioamateur stuff and try hard to
understand it. And I enjoy it all. Radio is about physics and you can't
change laws of physics because marketing department wants to. 
That is for me most comforting.
.