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BEFORE YOU START USING THIS TRANSMITTER...
It is a good idea not to rush things; get informed first about the various aspects of radio broadcasting. You will find
some very useful “How to” guides, answers to most common questions, a forum and tips on antennas at
http://www.pcs-electronics.com.
This is generally a good place to visit before putting your unit on the air. Also,
ARRL handbook is a very valuable printed resource on the subject of radio electronics and electronics in general. It
is released yearly and is found on every engineer’s book shelf.
HERE IS LIST OF THINGS YOU NEED TO GET CYB ON THE AIR
Antenna
Preferred type of antenna is affected by several factors, but mostly by your transmitting site. In the middle of the area
you want to cover you'll need an omni-directional antenna which transmits equally in all directions, while outside
your coverage area you can beam the signal in with a directional antenna. Before going on air get a low VSWR by
adjusting the position of the antenna and any adjustable pieces. Aim for 2:1 or less. Use low power into the antenna
when tuning it up and making adjustments. If you were using full power and a bit of the antenna came off in your
hand the VSWR could be so bad as to blow the final transistor. For the same reason check the DC continuity of the
antenna with an ohmmeter before plugging it in, to be sure it's what it's meant to be, either a short circuit or an open
one, depending on the antenna type. Please note that you won’t get a reading of 50 ohms, 50 ohms is supposed to be
antenna impedance at working frequency and your ohmmeter is measuring DC resistance. For instructions regarding
construction of antennas please see our website:
http://www.pcs-electronics.com
(guides section - antennas).
You should realize that antenna was, is and will always be a crucial part of the system. Special care has to be taken!
Your range largely depends how good your antenna system is. It is usually a good idea to place antenna away from
your transmitter, power supply and audio system. If you cannot meet these
requirements, you could experience feedback and other RF problems. We
cannot guarantee proper operation of any transmitter/amplifier unless
suitable antenna system is used! This applies to any transmitter.
Interestingly, strong RF field can make CD players and other digital
devices go bezerk. It can make them freeze or make them function erratically (if that happens, power CD player off
and back on). Most of the modern audio gear is not RF shielded – reducing costs is unfortunately the mantra today.
This is why keeping antenna away from audio gear and mains wiring is a good idea.
Coaxial cable
Coaxial cable is an electrical cable consisting of a round, insulated conducting wire surrounded by a round,
conducting sheath, usually surrounded by a final insulating layer. The cable is designed to carry a high-frequency or
broadband signal, usually at radio frequencies. Coaxial Cabling is a two conductor closed transmission medium that
is often used for the transmission of RF energy. It yields excellent performance at high frequencies and superior EMI
control/shielding when compared to other types of copper cabling. Coaxial cabling is commonly found in broadcast
and networking systems. Most coaxial cables have a characteristic impedance of either 50 or 75 ohms. The RF
industry uses standard type-names for coaxial cables. The U.S military uses the RG-# or RG-#/U format (probably
for "radio grade, universal", but other interpretations exist).
The common RG-58 from Radio Shack is NOT the best you can do and will lower your effective power out! Use it
only for short runs. BELDEN makes terrific coax in various qualities and with very low loss (measured in
dB’s…decibels). 3 dB loss = 1/4 of your signal strength - either lost or gained. Watch out for the correct
impedance…RG-8 and RG-58 have 50 Ohms. RG-59 and RG-6 (Low Loss Version of RG-59) have 75 Ohms. Most
antennas and transmitters including ours are 50 ohm. Check our website for good coax. Don't buy more than you
need to make the long run to your antenna and don't make up a few "jumpers" to go between your exciter, VSWR
meter and your antenna as all you'll do is create higher SWR and more line losses. H-155 or H500 are good choices!
RG-142 with Teflon is recommended for wiring inside cabinets, for baluns, Wilkinson couplers and everywhere
where resistance to heat is required as insulation won’t melt during soldering or operation.
A PIECE OF WIRE OR TV
ANTENNA IS NOT A SUITABLE
ANTENNA FOR THIS STEREO
FM TRANSMITTER!