800 Mhz Preamp ( In house signal amp )

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mancow

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I got one of these from a friend at a hamfest http://tinyurl.com/6mh26n

I don't know anything about the ebay auction or seller or anything. I'm posting the link for info purposes.

Anyway, my friend works in the cellular industry and he said they are 40 db gain with a .7 noise factor! Well, he must be correct. I hooked this thing up to my 800 Mhz omni and it's nuts. I ended up putting an 800 hand held antenna on the output of the amp right on my desk. The thing is sitting here running as an in building signal amp. The system I'm listening to can't be heard with a hand held. I could only hear it when the 996 was hooked to the 800 omni. However, with this thing re-transmitting everything in the room. I am now able to hear the system on my 396 ACROSS the room. It's awesome. NO MORE CABLES for 800 Mhz. All I have to do is just put a collapsed telescopic factory antenna on the back of a receiver and I get a full meter signal of anything the high gain 800 hears up on the roof.


Smooth.......... :cool:



 
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mancow

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It's not.

Actually, the 800 omni on the roof goes directly to the back of that box. You just can't see the cable in the picture. The box is an extremely high gain preamp. I attached the HT 800 antenna to the output that you can see in the picture. The box picks up the 800 signals from the omni, amplifies them and rebroadcasts them out of the HT antenna on its output jack.

I can go portable pretty much all over the house as if I was hooked up to the 800 omni directly with a cable.

how is this thing hooked up?
 

prcguy

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Hey mancow,
What a coincidence, you got one of those too? I found it has too much gain for average use and I suppose if you keep the roof top antenna (sucker) isolated from the in house antenna (squirter) it should be ok. I never thought of using it in that fashion.
prcguy
 
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mancow

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Yea man, it's an ass kicker. I meant to grab a few attenuators from him when I was at the fest but I got distracted.

Actually, he came up with the idea in a flip comment about how much gain it had that it could be used kind of like a BDA. I haven't had any feedback issues yet. I have a 2096, 996 and 15 all sitting here with just HT antennas on the back and I'm getting full meters on all with exquisite signal quality. It was just a temp type of thing but I think it's going to end up being permanent with the amp up on the shelf.

I noticed that it calls for 24 vdc but inside there is a voltage regulator so I guess they call for 24v to keep in line with regular run of the mill cellular base stuff. It seems to work fine with 12v.

Gotta love cell co. waste. :cool:

BTW, did you get my PM about the 148 batts? I'll let you know when they get in.
 
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prcguy

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If ya need some SMA attenuators, just let me know and how bout a 24v wall wart to run it? I forgot to do the batt thing, will take care of that first thing in the morning -Thanks!
prcguy
Yea man, it's an ass kicker. I meant to grab a few attenuators from him when I was at the fest but I got distracted.

Actually, he came up with the idea in a flip comment about how much gain it had that it could be used kind of like a BDA. I haven't had any feedback issues yet. I have a 2096, 996 and 15 all sitting here with just HT antennas on the back and I'm getting full meters on all with exquisite signal quality. It was just a temp type of thing but I think it's going to end up being permanent with the amp up on the shelf.

I noticed that it calls for 24 vdc but inside there is a voltage regulator so I guess they call for 24v to keep in line with regular run of the mill cellular base stuff. It seems to work fine with 12v.

Gotta love cell co. waste. :cool:

BTW, did you get my PM about the 148 batts? I'll let you know when they get in.
 

mancow

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Yea man, I could use the atts. but I see no reason for the p.s. due to the fact it's dropped internally. But thanks anyway.

No big deal at all on the battery deal. I just wanted to make sure you wanted them for sure.
 

af5rn

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Whoa! I'm not sure I understand exactly what is happening here. Is this thing working as a sort of repeater/extender thing? It's taking all signals input into it and it thinks it is shoving them down a coax to a receiver, but instead is blowing them out a rubber duck to be picked up by any nearby receiver? And it does so so efficiently that no coax is needed? This is very interesting!

What did you pay for it? Was it new or used? I am really liking this idea! Considering how much a good multicoupler costs, this could save us considerable money in a big shack!
 

mancow

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You understand it correctly. Your description is exactly how it works.

I paid around $10 for mine but that's because I bought it from a friend that was selling a few. I don't know if he has any others.

It works great but is only good for the 800-900 range.


Whoa! I'm not sure I understand exactly what is happening here. Is this thing working as a sort of repeater/extender thing? It's taking all signals input into it and it thinks it is shoving them down a coax to a receiver, but instead is blowing them out a rubber duck to be picked up by any nearby receiver? And it does so so efficiently that no coax is needed? This is very interesting!

What did you pay for it? Was it new or used? I am really liking this idea! Considering how much a good multicoupler costs, this could save us considerable money in a big shack!
 

KC0QNB

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Seems logical to me, I had mentioned to another user on here that one idea I had to help him hear what he wanted he could build an amplified repeater setup. I am glad this works for those who have tried it.
Nice tip! Hey is there a greatest tips forum on here?, if there isn't there should be!
 

andrewccm

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I want one.

Are you saying that you're using a 12v wall wart instead of a 24v? Or what? I am thinking about picking one up just for the fun of it...
 
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zz0468

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... and I suppose if you keep the roof top antenna (sucker) isolated from the in house antenna (squirter) it should be ok. I never thought of using it in that fashion.
prcguy
Probably not a problem if the thing only has 40 db of gain. It's those real BDA's with their 80-100 db gain that are a pain in the butt to isolate.

Clever idea! I like it.
 

jon_k

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Know where to buy one?

Secondly and most important, how is this legal to be rebroadcasting the traffic on 800mhz? Not only can it cause a feedback loop disrupting communications, but since you would be unlicensed to operate on that band and frequency, aren't you illegally broadcasting?

I'm not sure if the 800-900mhz band allows anyone to transmit under certain power levels. I'd just rather not lose my amateur license on account of retransmitting on the wrong band. (Then again, what band would be legal to re-transmit on? )
 

mancow

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I linked to an auction for one at the top of this post.

As for re-transmitting... I'm not worried. It's only a very low level of signal. There really isn't any commercial or PS 800 traffic in this County anyway.
 

andrewccm

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Ok. Silly question...

I have my ST2 and Yagi 800 up in my attic. If I hook this device up to my Yagi, would this in effect boost the 800 signal to my ST2 since it's relatively close to where this would be setup? Thinking that I could use this for broadcast to my 800mhz scanners and the one using the ST2 would benefit from the 800 directionality of the Yagi as well as the Omni 800 that it normally picks up (albeit, not as strong).

Any thoughts?
 

mancow

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No, the goal (in this fashion anyway) is to separate the internal antenna (one in shack) as far from the receive antennas as possible. Otherwise there could be feedback issues. Mine are all up on the roof and well away from the shack.
 

andrewccm

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Ok.

Wonder if having both my "external" antennas in the attic would be sufficient? I cannot place anything outdoors due to HOA. There is so much 800 traffic in my area and extended area that I'd like to do something like this to get more use out of my Yagi. Might be worth a shot anyway...I could always just resell it if there is a prob. I like tinkering.

Thanks again.. BTW: What power supply are you using on it?
 

andrewccm

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I went ahead and purchased one of these from the eBay seller. Figured I'd give it a try. Hope to have it soon and report back.
 

nosoup4u

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I just picked one of these up. So far the range only seems to be about 20 feet, although I am still playing with antenna combinations. I'm only using 12v also, but I do have a 24v PS coming shortly. My hope was to put this in the attic, so I would have a better 800Mhz signal all through the house.
 

andrewccm

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Mine came in and had a break in the solder joint between SMA and circuit board. I am sending back for replacement. Even 20 ft would work for me. I really just want the other scanners in my room to benefit from the single Yagi I have...
 
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