Transmitter Instructions
1. Attach the antenna and feed the wire out (later after testing you can put up more wire to cover the whole house better.)
2. Plug in your RCA to mini patch cord into the transmitter and into your source of audio (headphone level) Use a headphone and make sure you actually have audio coming out of the source.
3. Set the transmitter volume control to just barely on for headphone volume audio devices.
4. Plug unit into a 120 volt ac outlet.
5. turn on one of your radios and set frequency to 100 or 1000khz (or the frequency you had me set it to)
6. Tune your radio to that frequency and you should hear your programming near the spot you tuned the transmitter to.
7. Now that you have it up and working you may want to add more wire so that all your radios will receive the signal well.
8. Keep the Volume control on the transmitter very low, I pre-set it to 9:00 and seems to work well at that setting. (increase it if necessary)
9. If you need to change the transmitter frequency use a 2.5mm Allen wrench or best would be a plastic tuning tool 2.5mm, turn clockwise to go down frequency and counterclockwise to go up.
The Volume control and volume of your source audio will have to be adjusted a little to get everything sounding good, make sure your receiving radio is loud enough then adjust your audio source so the distortion disappears, what happens is if the drive either from the source or volume control on the transmitter is too high it will over modulate and make the waveform not what it should be and comes out as distortion in the receiving radio, so lean towards keeping it low
till you have it sounding good then crank it up slowly.
Post Script (PS) know the Allen wrench tuning sounds like a lot of bother but its worth it because
A “permeability tuned oscillator” (PTO) is more stable than a variable capacitor in that it will drift very little.
The famous Collins radios all used a PTO tuned oscillator and also the Drake
Line.
Suppose the reason other radio companies back then did not copy Collins is they had a patent on the PTO.
Other people make claims that their transmitter does not drift, but when a coil and variable capacitor are warmed up slowly by the heat of a tube the capacitor plates become thicker because metal expands when it is heated, and the coil becomes larger when the copper wire expands, what the result is the transmitter goes down frequency.
To compensate for what little drift mine has on the coil is a small negative compensating capacitor that looses capacitance as its warmed up, and like magic the transmitter drift’s very little.