27MHz power amplifier

[alah]

Hi everybody. I need a 27MHz RF 2,3,5 watt pwer remote controller.
The frecuency is because of the tres blocking my 1000m line of sight.
If anyone has suggestions, please let me know; Thanks.

 

[trash]

Any old AM CB is the source of all the parts you need to make a 5W amp.
You might however find that a good external antenna will make a big difference.
If you're using ~5 watts then you'll probably want a reasonable antenna anyway.

 

[alah]

Thanks, trash. It´s just that I know very little about wireless transmission.
Can anyone recommend frecuency and power for my scenario:
1000m and heavy vegetation blocking line of sight?

 

[ronsimpson]

2.4gh will not work!
Here we use 2.4gh and 5gh line of sight.
In town they are using 900mhz to cut through trees.
I believe 27mhz is better for trees.

 

[alah]

Thanks. People near should be happy! Simpson, ( not only that analog meter, Homero and family ), Ron ( I drink some ) and Love?land! You shouldn´t have any problems. Nobody contraries, two advised 27 Mhz, so I´m going that way. But the only equipment I´ve found is ELSEMA in Australia and shipping will ruin me! Any idea for homebrewing? Thanks again.

 

[ronsimpson]

Low frequencies work well when things are blocking the view.
On the other hand, high frequencies use small antennas.
At high frequency it is easy to build high gain antennas.
At 900mhz and 2.4ghz a gain of 10 is not very big.
Even at 27mhz a gain of 4 is not hard. Use a good antenna at each end!

 

[alah]

Thanks Ron. Now I´ve been investigating quite a lot and found a GSM solution. Equipment is around $150 and shipping ??. I can do it myself but, if anybody else calls my tank could drain! I can assign a ring tone to my master phone but NO idea as to HOW the receiver could identify it. Any idea?

 

[JMW]

Where are you located? If in the USofA, and you want to do this, you need to contact the FCC. You are not permitted to broadcast control signals without a license. Garage door openers, keyless entry, cordless phones, wifi, all have power and band limits.
There might be certain radio control products such as model airplanes that might be adapted for your needs, but you are not permitted to modify the output in any way.
If you inadvertently interfere with a legitimate licensed user, the penalties are quite onerous.

 

[alah]

Where I am almost NOTHING is illegal, matbe BEING legal. But what I¨m thinking about is just using two cells;
The first to call and I can use the audio output of the remote to control my relay ( Is that ilgal in USA?
My problem is that sometimes we´re assigned numbers which were used before or the remote could receive a wrong number call which could empty my tank. That´s why I´d like to assign my number a unique ring tone which could be identified as authorized. Is this ilegal over there? Any circuit which could help? Thanks.

 

[trash]

Here you go alah,
http://www.cbdomain.com/uniden_cb_hf_sch_downloads.htm
have a look at the Pro520e as an example.
Injecting your tiny signal into R114 is a place to start for this example.
Chances are that your controller will be a little too high power to inject at that stage, so you might choose to inject it further along the amplification chain or
just add some attenuation.

Now you might not have this specific CB. But you should have no problems finding any old AM CB for $5.