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Vibrations
is a normal problem for receivers and transmitters, their coils and crystals and filters have
microphone behaviour, pack in foam and also avoid loud sound
SWR
a video transmitter with a badly matched antenna and/or badly grounded will have high frequency
currents going on its signal and power cables.
When having range or interference problems, try to isolate different items, like turn it off, or change their
position dramatically or bypass its function until you find a change in your problem, then you have found
the noisy item.
Radio Technical knowledge
Any wireless radio system contain of a transmitter side antenna and a receiver side antenna.
Both sides must have same polarization to perform most optimal, the most common polarizations are
horizontal, vertical, circular left or right.
If a horizontal is “talking” to a vertical, the link loss will have an added extra loss of 26dB
If a circular left is “talking” to a circular right, the link loss will have an added extra loss of 26dB
If a circular left is “talking” to a vertical or horizontal, the link loss will have an added extra loss of 3dB
This is why it is smart to combine a horizontal or vertical often mounted in a plane, with a circular receiver
on the ground, then the 26dB drop can most likely be avoided.
Pointing a whip style antenna to a plane is the worst thing you can do, imagine looking into the end of the
whip, It is almost impossible to see from a distance, radio waves work this way too, make antenna most
visible and right polarization.
It is normal that radio links have a 26dB extra margin in its link budget / range calculation so you don’t lose
contact - when one antenna is rotated unlucky angle, a diversity system can take full advantage of its link
budget, so the resulting useable range is almost 10 times as much as a non diversity system, if no other
parameters are changed.
