8 scanners with 3 antennas in a shack setup

I am looking to create an 8-scanner dispatch center (news media) in our office. For the last five years I've had a bunch of scanners with two cheap Radio Shack discone antennas and tee splitters. It works, but I know I could do better. And I'm skeptical if it would work with all 8 scanners using tees.

7 scanners monitor 800MHz, 1 scanner monitors 39/151MHz. Of the 7 800MHz scanners, 5 of them monitor 2 strong systems and 2 of them monitor a distant system that comes in a little scratchy but it's tolerable. Thats why I'm thinking a directional antenna would be ideal for the distant system.

39/151 MHz Antenna --> 1 Scanner
800MHz Antenna --> Stridsburg MCA208M --> 5 Scanners
800MHz Directional Antenna --> Stridsburg MCA204M --> 2 Scanners

I'm pretty confident that the Stridsburg active multi couplers are what I'm looking for, although I'm open to ideas. What I'm still unsure on is the coax and the antennas. They will be mounted on a 60ft long x 25ft wide metal roof with a run of about 30-50 feet per antenna. I want the best coax but not so stiff that I can't work with it, and it must be able to be terminated to BNC.. I strongly dislike using adapters. I like to buy the right stuff once.. I don't want to have to replace it because I bought cheap coax. But I've also seen some pictures of some beefy looking coax that looks no fun.

What coax and antennas would you suggest given these factors?

How about one nice wide band antenna and a run of LMR-400 going to a Active Multicoupler then to the scanners. And if you could get the antenna on a tower.

That is the way I'd do it. Here is a active multicouer http://www.scannermaster.com/8_Port_MCA208M_VHF_UHF_Receiver_Multicoupler_p/02-530558.htm

A wideband would work for 6 of the 8 scanners since the MCA208M covers 39/151/800 MHz, but I still think a directional antenna would be necessary for 2 of the scanners.

Also, what would be a thinner coax that can be terminated as BNC? It would appear LMR-400 needs to be terminated PL-259 or similar. I'd prefer to avoid adapters, unless the benefits of LMR-400 outweigh the signal loss/interference by using an adapter?

How far area you trying to hear that would need a directional antenna?

LMR-400 can be terminated in to multiple fittings. Type N and even BNC. The 400 would be the main run to the Multicoupler. Then from there you'd use RG-58 to the scanners. No adapters needed.

Looks like you have the right idea. Stridsberg is certainly the gold standard for multicouplers. If some of those 800 MHz signals are really strong, you might consider just using 'local' antennas.

BTW, the link King posted is for a Stridsberg, too even though the web page title doesn't say it.

And yes, 8-way Tee splitters will likely cause issues - mostly with scanner-to-scanner interference.

The coax is iffy since you want good, but not stiff. Maybe RG-8X might work? I've never been a big fan of LMR400. Personally, I would use 1/2" Heliax, but I wouldn't call it easy to work with. It definitely fits the "buy it once" class, and low loss, and durable.

Not sure how you feel about it, but maybe get a local radio shop to install everything and save yourself the trouble and get a regular setup for radios (commercial antennas minus the 39/151 MHz one).

And whatever you do - stay away from UHF connectors - especially at 800 MHz.

Kingmobileaudio said:

How far area you trying to hear that would need a directional antenna?

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Let me preface this by saying there are three 800MHz systems: North, South and City.

I am in the South system area. I can pick up the City (to my west) system quite fine as well. The North system, as far as I know, is intentionally designed to not be picked up where I am, so as to not cause interference with each other.

With the same 8 scanners in my vehicle, if I drive 10 miles north, I can pick up the North system much clearer. Granted, that is comparing apples to oranges (3dB gain vehicle rooftop antenna per scanner). That doesn't seem very far, but that is just how the systems are. And again, I can monitor the North system where I am, but it comes in scratchy and I'm looking for crystal clear audio. I think if I carefully use the map coordinates of one of the North system towers, I can point a directional antenna and slice through much of the RFI in the area. The North system antenna wouldn't benefit by me receiving RF from the west/south/east.

Voyager said:

The coax is iffy since you want good, but not stiff. Maybe RG-8X might work? I've never been a big fan of LMR400. Personally, I would use 1/2" Heliax, but I wouldn't call it easy to work with. It definitely fits the "buy it once" class, and low loss, and durable.

Not sure how you feel about it, but maybe get a local radio shop to install everything and save yourself the trouble and get a regular setup for radios (commercial antennas minus the 39/151 MHz one).

Click to expand...

Do you recommend a specific brand of 1/2" Heliax?

And what is "a regular setup for radios" ?

I am avoiding doing a tower due to added cost and the distance to the nearest location where I could erect a tower (at least 80 feet away horizontally). I'm planning to do an upside-down "U" pipe going through the roof/wall into the office, providing the shortest distance between antenna and the equipment. The antennas will be directly above the office.

You could also, if your local RX doesn't pan out, just put a scanner in the north and control it remotely at your office.

Stringer619 said:

Do you recommend a specific brand of 1/2" Heliax?

And what is "a regular setup for radios" ?

I am avoiding doing a tower due to added cost and the distance to the nearest location where I could erect a tower (at least 80 feet away horizontally). I'm planning to do an upside-down "U" pipe going through the roof/wall into the office, providing the shortest distance between antenna and the equipment. The antennas will be directly above the office.

Click to expand...

There are several brands. CommScope being one of the more popular.

A "regular setup for radios" would be the same installation as you would have on your local police or fire station. Likely this will be using 1/2" Heliax at 800 MHz, and using a directional antenna. You would want as many elements as possible (practical) to maximize range. They may also be able to do a propagation study to give you an idea if what you want is even possible.

And yes, as close to the scanner as possible/practical.

I agree that Stridsberg multicouplers are the way to go. I have been using them for many years, never had a single problem. Stridsberg will update your multicoupler at no charge for life.

If your reception is ok at 151MHz I would put up a specific full size antenna for 39MHz, a Discone for 151MHz plus general VHF/UHF and a high gain 10dB 800MHz omni and connect them all to a triplexer, which will combine them all with very little loss.

This will give you great performance on 39MHz where small antennas are lacking, good performance at 151MHz but also VHF air and UHF if needed and the best omni directional performance on 800.

Put the Triplexer on the roof in an outdoor enclosure and then you only need one run of good coax to the radio area with an 8-port Stridsberg multicoupler. For runs up to 50ft LMR400 would be fine at 800 and you can also put an 800MHz preamp at the antenna (in your new outdoor enclosure) before the Triplexer to boost that band if using a longer run of coax. Since your other bands of interest are not a loss problem with LMR400 you could easily go 150ft with a preamp on the 800 side.

I have a similar setup at home although it doesn't get used much. I have separate, big commercial high gain omni antennas for every band 30MHz through 1.2GHz feeding an Austin Pentaplexer. I don't do much public service scanning and end up tapping into my individual antennas for feeding various transceivers, but when its all hooked up it can provide a scanner with the best weak signal grabbing feed possible.
prcguy

From the roof, can you hear the north system with a handheld (no coax loss)? You could buy an 800MHz yagi first and test it from the roof with a short coax jumper.

Stridsberg also makes the MCA804/B 4 port multicoupler. It is specifically designed for 800MHz. A word of caution with the 804, it is not designed for 700MHz so if your system uses both 700 & 800, you will not be happy. They also make an 800MHz preamp, A8020.

LMR 400 for a 30-50' run is more than adequate. Terminate in N connectors.

I would use 2 antennas, 2 runs of coax and 2 multicouplers.
Discone or other multiband antenna
800MHz yagi
LMR400 coax
Stridsberg MCA804/B with N connector input specified (if you also get the preamp, specify N connector as well)
Stridsberg MCA208M 8 port multicoupler with N connector input specified.

chris