Hello Wesley,
Many thanks for all that info.
Here in the UK we are only allowed 4 Watts...... Legally!
But do we really need an RF transmitter? Can we not just build an RF oscillator? Or more lateral thinking a variable frequency HF signal generator through some sort of amplifier?
Cheers Grum.
Do not confuse Civil Band 27Hhz with ham radio !!
transmitter is generator as well
you need power and signal generator is not giving you much. usually mW or few W
Usually signal or function or arbitrary signal generator is more expensive and yet
if you have one
-as long as you are able to drive input of PA ( power amplifier)
you can use it with PA
PA are very inexpensive with 200W range.
from Hamfest you can pick them up for few bux.
Google for Hamfests in your area- great for all sort of cheep elements right to your hands.The best one for anyone anywhere.
Advice:
1. NEVER BUY NEW ONE.!!
2. THERE IS NOTHING TO BLOW IN pi filter based TUBE PA APART FROM TUBES
3. input of PA must be as low as possible in driving power to use generator
if it is to high than smaller amplifier is serving as preamp.
4. when doing experiment sometimes kWts of RF does not bring/never bring, anyone attention you are not important to authorities
and you not transmitting in frequent basis.
5 to catch interferer takes money.
For years Ham Radio interferers transmit and it is hard to bring anyone of authorities attention
They Do not care,
For 50 dollars you can buy so much you would not believe from Hamfest.
legal power in UK is hm........ I think 200W for HF 21MHZ
in here 1.5kW
Amplifier ( linear)class A ,AB does not care what you connect to it.
Amplifier has input and output
Output can be connected to dummy load, any load of impedance matching around 50 ohm
or antenna 50 ohm
for purpose of experiment RF does not have to be radiated out far.
resonance circuit of HF amplifier using knob delivers signal than in
near field not far field to output resonance circuit
for that you need to understand that any dipole antenna when coiled up might be close to frequency of its design - only with much narrow bandwidth- usually after coiling it lowers its resonance response
but in typical pi filter you do not even think about it as tank capacitor is taking care for impedance mismatch
in some instances you might need antenna tuner that is your matching network
Ten Tec 229A legal limit antenna tuners - means could handle 1.5kW from transmitterAntenna tuners are always between output of PA and antennain our application they can serve as tuning resonance circuit of any power at input of tuner.Antenna tuners do not have any tubes and do not amplify anythingThey are simply impedance matching devicesbetween impedance of device connected to input and device/antenna/ circuity connected to output.
http://www.ebay.com/itm/Ten-Tec-229A-legal-limit-antenna-tuners-/130886588621?pt=US_Radio_Comm_Tuners&hash=item1e7972d8cdI can have any overlimit power at home as long as I do not radiate out.
Owning something is not equal with using it to transmit.
Wesley