Power boost for specific frequency

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TannerNM

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Hello! I am a falconer and we use 216 MHz radio transmitters/receivers to track and recover lost birds. As the size of the falcon wearing the transmitter decreases, so does the size and power of the transmitter. I fly very small birds and would like to improve my ability to track them.

I would like to investigate the possibility of adding an additional amplifier (preamplifier?) to my receiver system but I am not an expert in this area. One product that I came across is this thing:

GRE Super Amplifier Preamp

that seems to be along the right lines (?). But I am wondering if a narrower band solution exists or if there might be something that could plug into my truck cigarette lighter that would be more powerful?

I am a total amateur in this area and appreciate all feedback! Thanks!
 

zz0468

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I would try a better antenna before I tried a preamp.
That actually sounds like it might be the perfect application of a good preamp.

To the OP, I'd suggest you contact Angle Linear with your requirements. They understand unusual applications quite well. Just Google the name.

An alternative would be Advanced Receiver Research. They have a line of preamps that would work well.

I would suggest you stay away from the GRE amp. You'll fare much better with either of the two suggestions above.
 

TannerNM

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Thanks for the comments fellas. I'll do some head scratching about each of the suggestions. Don, with regard to antennae - I have a yagi that is pretty good while in the field, and also a rooftop omni that was given to me - on the omni, do you have suggestions about tuning for length, etc?

I'll check in on the military monitoring and the suggested preamps above. Many thanks again!
 

TannerNM

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Power Supply Suggestion?

I received my P220VDG yesterday. Through reading the installation guide I realized the requirement for a 11 - 16 V, 25 mA regulated power supply (suggested to have crowbar protection). Can anyone recommend one to me please that could be powered from a car cigarette lighter, if such a thing exists? I notice also that common-grounding of the input, output and supply ground is also important - would a ground lead from the shell/shield of the preamp input and output bnc's screwed to the truck body be acceptable here?

Thank you in advance for your help.
 

TannerNM

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Alright, I got to try my new preamp with my set-up last night a bit. I will need more measurements but the upshot is that it works pretty well. Assuming that my power meter on my reciever is linear, I get a factor of 4 improvement in signal strength at a decent working distance. I tried also driving with my omni on my truck until I could no longer get a signal, then put the preamp inline a picked up a decent signal again. I didn't have time to do any more quantitaitve measurements.

I think I need to address my omni to improve performance at this point. One question I have is about the connectivity within the antenna. I have one that was given to me where the ground/shield of the coax are in electrical contact, on purpose, via a coiled section of wire in the base of the antenna. The coiled section is laid on a machined piece of nylon so that the spacing of the coils is even (inductance/transformer????) and I don't know what the function of that is. I went ahead and disconnected the part that connects to the coax sheild. Now the center coax conductor is only in contact with the antenna whip.

Did I do the right thing? What is the nature of that setup, before I modified it??

Thanks for all the feedback, I'm learning a lot!
 

zz0468

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Alright, I got to try my new preamp...

...I tried also driving with my omni on my truck until I could no longer get a signal, then put the preamp inline a picked up a decent signal again. I didn't have time to do any more quantitaitve measurements.
Sounds like it's working. Without test equipment, the best you can do is a comparison like that, and hope to see an improvement.

...I have one that was given to me where the ground/shield of the coax are in electrical contact, on purpose, via a coiled section of wire in the base of the antenna. The coiled section is laid on a machined piece of nylon so that the spacing of the coils is even (inductance/transformer????) and I don't know what the function of that is. I went ahead and disconnected the part that connects to the coax sheild. Now the center coax conductor is only in contact with the antenna whip.

Did I do the right thing? What is the nature of that setup, before I modified it??
Without knowing what the specific make and model of the antenna is, it's difficult to know exactly what the designer had in mind with that coil, but it would be safe to say that it's essential to the proper operation of the antenna at it's design frequency. But we don't know what that was, so by taking it off, you may or may not improve your observed reception. But I would venture to guess that whatever was intended, the antenna is no longer operating in the manner it was designed to.
 
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