Famous Czech manpack radio set for a short range
communications. Very probalby based on (not only) the idea of
the RF-11 was the first post-IIWW small manpack radio. Its concept is
very simple, VFO-PA while transmitting, preamp and superregeneration
detector while receiving. There were three variations of this radio
produced (in the order of appearance):
- RF-11 - the primary model, uses 23-28 MHz band, thus, is compatible
with e.g. A7b and other radios of these times.
- RF-11M - modified version, now in the 48,5-51,5 MHz band.
- RF-11M/2 - almost the same as RF-11M, slightly modified circuitry.
The radio is equipped with four 1L34 tubes,
tube in the quartz calibrator box. Powered form three "D" size dry cells
for a filament and one 120V anode dry battery, the radio can run for
about 12 hours of operation. Very good documentation can be found here..
The field operational results of those radios were mostly poor -
mainly because of the low sensitivty, bad reliability and low frequency
stability. At the other hand, there were no other such a radios in our
country at those (and many following) years...
All photos are © OK1UHU, 2011