VCR RF Power

[trev]

What exactly is the RF Power output from a VCR? Can this be increased using a good quality masthead amplifier and Triax grid UHF aerial?

[Mike]

Yes but its usually not a good idea since

1) If you use Channel 36 Youre liable to interfere with other peoples Videos
2) Very few videos have vestigal sideband filtering so youre actually using TWO channels instead of one
3) With TV3, TG4, Channel 5, new relays, RSL's, Deflectors , Fringe reception of cross border/channel/region stations and Digital TV the UHF band is now quite crowded

If you do transmit on UHF remember the need to watch out for +5 (IF) and -9 (Image) channel relationships

[Original Tyrone Gobshite!]

I wouldn't be terribly familiar in doing this(!) but one thing that I was always told is that to boost the signal you would need a linear amplifier - dunno if a simple mashead would be capable of this.

It seems to be those who try this technique are able to send pictures to about a few hundred meters, though there would be many factors in this (it is often tried using the output of Sky Digital receivers to send pictures to a friends house!)

If you actually set it up correctly using the right amps, directional aerials (TX & RX) and everying was done on board it would travel further. The actual power sent out from the VCR RF is often between 1-5uV.

[Mike]

A masthead would give a small amount of gain but with the high signal level coming from the video it would probably saturate and the output wouldnt be particularly clean.

Also if you had an aerial connected to the RF input on the video as well you could get a feedback loop which could be very nasty (interference across the band)

[Arnold]

As above have suggested the masthead amp is a non runner, you could run it straight into a high gain (ie long thin not bread tray) aerial.
I did it years ago for no particular reason and got about 50m down the road!
I have recently seen a 1 watt uhf amp designed for this purpose on a pirate(ish) site in the States but don't remember the url, sorry.
N.B. VCRs don't output in stereo on RF

[Megawatts]

Try using Panels, and then use high gain Yagii to receive.
Using yagii to transmit leads to problems on the length of the directors. You can lose an awful lot in the balun, on the dipole.

Better to use Panels, and stack them in a phased array.. BUT just joing them, may end up giving more loss than the extra gain you get.

There a high power Cable amps, that are availble.

Putting it simply.. you could plug one of those domestic 8 ouput amps, and use the "full output" socket.. thats the one that gives the full amp gain.

I have a Band 1,2,3 Linear 1KW if you want... if you want to use Band 3... It is designed for TV, being a Linear Amp:cool: