The ATLAS 210 transceiver is supposed to be linked to an antenna having an impédance of 50 ohm .In case the antenna is not perfectly tuned to the frequency or the impedance is above or below the 50 ohm mark reflected power will be send back to the transceiver ..To protect the final amplifier the ATLAS 210 has a built in SWR protection .If the SWR increase the power output will be reduced .Therefore to get the maximum output you need a matching device to make your transceiver happy .There is no need to invest in commercial antenna tuners as some are even more expansive than the ATLAS 210 by itself .One good choice not to use a tuner at all is to use resonnant antenna like quarter wave or dipole .THese antennas are very easy to built and have very decent performance .However their impedance are rarely equal to the 50 ohm asked by ATLAS and you will need some device to adjust the impedance .
very simple antenna tuner to use with ATLAS 210 is the L COUPLER
.It needs only a variable capacitor 3 switches and an inductor
.The variable capacitor can be recovered from an old receiver .Its
capacity should be in the 500 pf range .The useful range is
extended by a fix capactor of also 500 pf with can be put in operation
by a switch .Both the variable and fix capactor can be linked to
the inductor by another switch . The peak voltage for the
capacitor is not very high and always below the 200 volt mark for
an output of 60 watts .No risk to see some arcing between the
plates . Everything can be packed in a tiny plastic box .The coil
is made of copper (diameter 1 mm or above ) .The diameter is 1.6
cm it has 23 turns on 6 cm length .Theres is taps every 4
turns each being link to a rotary switch (Big schematic )|
|HOW TO OPERATE|
The tuner is linked to the ATLAS using standard coax cable .You have to find by yourself the right combination for the inductor and the capacitor to get the minimum amount of reflected power read either from an external SWR meter or from the built in reflectomer as shown elsewhere on this site .Do not forget to switch the capactor from one side of the inductor to other side in case you are not able to get a low SWR. With this device you will be able to get the full output for the ATLAS 210 transceiver even if your antenna is not perfectly tuned to the frequency of operation .