Been collecting bits for this project for a while.
The idea is to have a CCTV camera mounted on a tripod transmitting a picture of the target in use at the range.

The transmitter that fits on the camera has a 1/4 wave b̶i̶t̶ ̶o̶f̶ ̶w̶i̶r̶e̶   antenna, it might work ok at 100M but I'm not convinced!

1st job was to build a Yagi 20 element with around 15db gain.
This should do the trick...

In the mill to drill the holes in the 3/8" glass fibre rod.



Populated with elements.


Finished with coax connected.


Will make a tripod adapter and add further photos later!

Camera plus transmitter.



Two receivers and composite to VGA adapter.

Waiting for pictures of remote targets...

Paul

you aint the only one....

send me one up Joe and I can give it an "unbiased" test!!!!
what would be cool is to have one on a bear bait with real time feed!!!! how far can you get one to transmit? God Bless.

This is line of sight only, David, and I'd GUESS about between a quarter and half a mile with the yagi antenna.

Paul

Always problems with line of sight! I'm hoping that because this kit will have an uninterrupted view that I might get a usable image, honestly I do not have much hope even with a '15db yagi' (just a guess) - I don't want to mess about with the spectrum analyser etc to find out....

Honestly, I think if you can get 12db gain from the antenna, you should be 'good'.

The decibel (db) scale is on one hand a VERY simple logarithmic scale. Of course voodoo priests, charlatans, and outright liars have screwed it up completely. 12db of gain COULD mean a two-fold improvement in signal-to-noise ratio, (SNR), or it could mean a four-fold increase. Depends if "they" want to talk "power" or "voltage". For most of the "antenna" folks that I have dealt with, 12db would be a four-fold increase in SNR.

Based on my training (paper-whipping theory), I am more optimistic than j0e_bl0ggs is, but he has considerably more hands-on experience than I do with antennas. My optimism is also founded on experience - experience in seeing j0e_bl0ggs get things to work.

Paul

What I can recall from my 20 years as an amateur  I believe 12 DB would give a 4 times increase in s/n .
David.I believe your best bet would be a motion activated camera and a receiver with a hard drive or stick memory.
For real time, I would imagine you would need a repeater with a signal converter for 2m or there abouts.
I am far out of date on radio and TV, I still think in vacuum tubes and discrete components.

3dB doubles power, 6dB doubles voltage, so it depends on whether you're measuring s/n in watts or volts. Give the system over to Madison Avenue, and you get complete ****. In general, physicists and electrical engineers like to use different variable names for the same thing. One that really chaps my cheeks is the "imaginary" operator (associated with determining phase relationships). The physics guys use "i", but the EE guys use "j" because "i" is used for current. I could go on, but it wouldn't solve anything. I have been annoyed by petty bickering - at the expense of clarity - between various scientific disciplines since I first got into college. For all my complaining, NOTHING has changed.

Paul

Amateurs are usually interested in power levels, not voltages.
Most of the video cameras I have seen advertised have a very limited range, so you would have to do something to increase the range.

True, but voltage meters are WAY more available than power meters. Then you need to differentiate between bands. Sound pressure level (SPL) meters actually MEASURE voltage, but REPORT "power". Most radio stuff I am familiar with REPORT "power", but are, in general, cryptic about what they are actually measuring.

Honestly, it's a MESS, and the sons of bachelors KNOW it and TRY to make it as confusing as possible except for those in the particular priesthood they are in.

Paul

In making beams, we were concerned with forward gain, angle of beam width and front to back ratio.
The pursuit was to increase the S- meter readings at the other end, especially in the beginning of the solid state component era.
For a while, there was a competition to see how far,(DX), was possible with QRP,(very low power transmitters) and , before a lot of encapsulated components and any smd's were available, to build the transmitter in a 1" cube.
These were mostly on 20 meters, 14,000 kc.
Yes, I am still a cycle oldster, I was offended when the powers that be decided cycles should be replaced with"Hurtz".
It is not transparent and informative, Hertz did not invent radio waves, he just managed to find a way to detect them.
Oh , well,just beating a dead horse,  or old German, as the case may be.

I don't like units named after people because the name then becomes meaningless. Cycles per second, etc. tells you exactly whats going on. Hertz tells you nothing. Yet ANOTHER 'tool' to make priests.

Paul

Got around to try the gear out today with the new transmitter/receiver and it all worked ok, the yagi gave by far the best reception.
Did note that xmitter antenna needs to be up in the air, being close to ground attenuates the signal something rotten - will have to make some sort of pole.
Did not take any photos but bruv n me got some trigger time!
Certainly was far easier than faffing around with a high mag spotting scope, target strikes were plain to see...nice!