Thread: modulator
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Old 02-20-2015, 08:12 PM
Electronic M's Avatar
Electronic M Electronic M is offline
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Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
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First off make sure your antenna is TUNED TO (ie cut to the proper wavelength for) the channel you wish to transmit on.
I first tried my modulator on a pair of all band rabbit ears, and could hardly get 30' of range at max transmitter output, but with a tuned dipole I could could get the same range with MINIMUM transmitter output, and several times that distance with the output maxed.......

...Which reminds me, do you know what all the pots with flat head screw driver adjustment on the unit do? If not here is a run down on how to set them: Output level should be maxed (until you know the max transmit range, then back it off a bit if the signal travels farther than you are comfortable with). The audio and video level controls are also important to set. Tune in a TV to the signal and increase the video level until you see fine bars/noise in the picture and the synch gets messed up, then back off until the picture is normal. The audio and aural carrier should be tweaked the same way up until distortion, then back off until good again. Some models have over-modulation indicator LEDs....You don't want them to light more than the faintest amount...Back off controls till they JUST go out.

Channel 7 seems to work best on my BT agile modulator too. Channel 2 gives me about 2-300' radius, channel 7 gives me about 1 block radius, and 9 gives me about 3/4 block radius. 3 and 4 are not used to protect VCRs being used with their RF out, 5 is DTV occupied here, 6 has too much interference from 5 to be used, 8 is also DTV, and I don't have enough modulators to bother with channels over 9 presently.

BTW I don't recommend using wire thinner than lamp cord strands for the dipole antenna leads....Thickness of the dipole wires is directly related to antenna bandwidth and a 6MHz NTSC TV signal has a whole lotta bandwidth....They did not make roof top TV antenna wires finger thickness just for resistance to wind damage, they wanted the entire bandwidth of the signal to be strong, clear and flat.
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Last edited by Electronic M; 02-20-2015 at 08:20 PM.
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