800Mhz Yagi

[rmiller818]

So I want one to improve my reception. Is it safe to assume any of the ones being sold for cell phones would work just as well? What about the cable that would come with that, anything to consider or is it good enough?

Finally, any recommendations on a specific antenna?

 

[k8tmk]

I built a yagi from an article in Popular Communications approximately a year or so ago. It was cheap, easy to build from readily-available materials, and works great!

Randy

 

[rmiller818]

Is there a link to that online?

 

[Baley]

So I want one to improve my reception. Is it safe to assume any of the ones being sold for cell phones would work just as well? What about the cable that would come with that, anything to consider or is it good enough?

Finally, any recommendations on a specific antenna?

I purchased this one and it works really well. The High Gain Dual Band Cell antenna. I can get most of Atlanta PD traffic from Kennesaw Acworth area. Its VERY well made.
Antenna Warehouse

 

[k8tmk]

I don't thinlk there is a link to the Pop Comm article online.

After I thought about it, it may be in the June or July 2007 issue. I can't seem to find mine at the moment to be sure which issue.

Randy

 

[code3cowboy]

If you are using it for a scanner it should work just about fine, and two or three year old cellular stuff is normally available free from cell companies.

 

[rmiller818]

If you are using it for a scanner it should work just about fine, and two or three year old cellular stuff is normally available free from cell companies.

How would one go about getting that stuff? Just call them up and ask?

Once an antenna is decided on, how would I go about choosing the right cable? Best case scenario I would end up splitting it to 4 scanners.

 

[rmiller818]

Another question,

Whats the benefit (or is there one) to having more elements?

Specifically, what is the difference between a 3 element and a 6 element? (other than the number of elements) How should that factor into a decision.

Also, if it were to be split to feed 4 different scanners, would that affect it?

 

[sjlamb]

Another question,

Whats the benefit (or is there one) to having more elements?

Specifically, what is the difference between a 3 element and a 6 element? (other than the number of elements) How should that factor into a decision.

Also, if it were to be split to feed 4 different scanners, would that affect it?

Generally speaking, more elements = greater gain. As for the splitter; yes.... at least to some degree. Anytime you "break" your feedline... be it a splitter, accessories,connectors, etc; you have "insertion loss" which amounts to reduced antenna gain.

 

[rmiller818]

So it would probably be best to go with the 6 element since it is to be split. Then I would need to figure out the best cable to use.

 

[rmiller818]

Here is my idea. I take a yagi like this:

800 MHz 6 dbi Yagi Antenna, 806 - 902 MHz, 4 Element - WLANMall.com

Use a N female to BNC male adapter and connect it to a splitter like this:

4 Port MCA204M VHF/UHF Receiver Multicoupler - 25 MHz to 1 GHz

Then run cables to each scanner.

Would something like this work? Is 6 dbi enough?

As far as cable, I am not to familiar with what to use, I have seen mentions of RG6 which I recognize as regular cable used for cable TV. I have some pieces of RG6 and RG59 but they all have the connectors to connect to your TV (F type?) So could I just use a bunch of F female to BNC male adapters to connect it to the scanners?

 

[rvictor]

Since you are talking about a beam for 800-900 MHz, I assume that all four scanners are going to be listening to 800-900 MHz. You might be better off with a narrowband multicoupler.

As for the type of coax, that's going to depend a lot on the length of the run. As the length gets longer, the need for better coax becomes greater. With RG-6 you're going to lose about 6db at somewhere around 70 feet. You can reduce that substantially with better coax. The calculator here will help you figure out the cost/benefit

Coax Calculator

Dick

 

[rmiller818]

Thanks for the link. Yes, all are used to monitor the county 800 P25 LSM system, trying to overcome multipath.

Are there multicouplers made just for 800 Mhz?

Also if the antenna is say 6dbi and through loss on the cable comes to 6dbi, would that effectively make the antenna useless? Like canceling it out?

Thanks for all the help.

 

[rvictor]

Thanks for the link. Yes, all are used to monitor the county 800 P25 LSM system, trying to overcome multipath.

Are there multicouplers made just for 800 Mhz?

I'm not sure exactly what's available, but I did a search and noted that the narrowband multicouplers appeared to emphasize lower noise figures. I think you may have to do some digging for the specifics.

Also if the antenna is say 6dbi and through loss on the cable comes to 6dbi, would that effectively make the antenna useless? Like canceling it out?

It may cancel out the gain, but you've still got a directional antenna that's presumably high and in the clear. If you used a lesser gain antenna, you'd end up with a net loss instead of breaking even as it appears you might do here. Besides, if your reason for doing this is to eliminate multipath, the gain may not be the issue as much as the directional nature of the antenna.

Dick

 

[rmiller818]

Hoping I won't have to put it up very high, I am relativly close to 3 towers so I guess we will see. I think I will order the antenna and connect it directly to one of my scanners and see what I get and go from there.

Thanks for all the help, I'm sure I will come up with some more questions.