hf transmitter
Dear all
during my last recurrent on the challneger i asked the instructors the reason why when we tune an HF frequency at first contact we have to press and hold the transmission key until we hear a tone - it normally takes a couple of seconds -. The answer i was given is that during that time the unit adjusts its transmit signal to the HF wavelength: as matter of fact the HF antenna is much shorter than the signal wavelength.
Can anybody shed some light on the relationship between the wavelength and the size of the antenna? does it have to do with impedance matching and if so what does that exactly mean in plain english?
is it a true statement that this process is not needed for VHF transmissions due to the fact that as the wavelength is inversly proportional to the frequency, the wavelength of VHF transmission is shorter than the wavelength of HF transmissions and thus more suitable to the size of the VHF antenna?
Many thanks
Baobab72