[HATS] Looking for some help/advice with a 900Mhz FM-ATV project/idea I have.

[TOMSMB@aol.com]

In a message dated 10/3/03 1:15:46 PM, spark51@attglobal.net writes:


> Also, since the audio subcarrier is down several dB from the video, the
> audio output power requirements are lower than those for the video.=A0 I s=
eem
> to remember about a four to one ratio -- but check it out before doing any
> serious design.
>=20

For separate transmitters the level is -7 to -10 dB as radiated from the sit=
e=20
in the same direction.   A mix system is -15 to -18.   So this is why a=20
separate TX in an AM ATV system goes so much farther.   You can still get so=
me=20
lower sideband sound transmitted even with a separate upper sound transmitte=
r=20
depending on the amount of sound transmitter energy gets picked up by the vi=
deo tx=20
antenna and mixes in the final amp to be re-radiated - intermod.  =20



Tom O'Hara W6ORG
P. C. Electronics
www.hamtv.com
626-447-4565 m-th 8 AM to 5:30 PM


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