Stacking Multi-couplers?

[dlwtrunked]

Stacking Multi-couplers

Lets get down to known math--as there is such. When cascading amplifiers, Friis formula applies
see Friis formulas for noise - Wikipedia, the free encyclopedia
From that one sees, what many already know, one wants a first stage with a good noise figure and fairly good gain as these drive the formula for later stages. Noise does not add but follows the formula there.

A good idea would be a good low noise pre-amp infront of passive splitters (that will not of course isolate interference of the LO from one radio getting to the otheres). Stridesburg makes both passive and active preamps. I have used both as above.

A few other things:
1. As has been said you can overload a receiver by giving it too much signal--so some tweaking of gain using different amplifiers or attenuators may be needed.
2. You may need other notch filters--*every* scanner user should try a cheap FM broadcast notch filter (Radio Shack may still have these). Even if you think you do not have a problem, there is a good chance you do. No, you will not necessarily hear the FM broadcast station if you do, it will simply "de-sense" your radio.

 

[N9JIG]

Here is what I have going right now:

The antenna comes in from the attic with a quad shield RG59. It goes into a Winegard DA1009 TV amp (a high quality TV amp from about 10 years ago). Coupled directly to the output with a double male F-Connector is a decent 3.5 db A-B splitter. Each output of the splitter goes to a Stridsberg MCA208M multicoupler via a short piece of RG59. Each MCA208M then feeds 8 scanners (4 BCT15's, 3 BCT15X's, 4 PRO2096's, and one each of BCD996XT, PSR600, PRO197, PRO163 and PSR410).

This seems to work very well. I have noticed that one of the BCT15's is hearing a VHF highband signal from 40 miles away at full quieting that my R8500 on it's own identical antenna (no amp, connected directly to the radio) didn't hear at all.

As I don't have access to test gear all I can say is it seems to work well here. I might try one of the MCA208M outputs on my R8500 and see how that compares with the antenna going straight in.

 

[chipjumper]

Is there a problem with using 75-ohm "tv" cable from the antenna to the multicoupler and then 50-ohm "radio" cable from the multicoupler to the radios? (referenced to scanners only)

 

[zz0468]

Is there a problem with using 75-ohm "tv" cable from the antenna to the multicoupler and then 50-ohm "radio" cable from the multicoupler to the radios? (referenced to scanners only)

It's less than perfect, but in the real world, you'll never notice the difference.

 

[737mech]

Digital Loggers

I read all the posts here about stacking stridsbergs but has anyone seen or tried the digital loggers 16 port multicoupler? I was thinking of going that route, not that I'm up to 16 scanners but expansion room is always good. Opinions?? Wideband RF Multicoupler - 16 Radios, Surge Protected, 50 Ohm

 

[wise871]

I know this is an old topic but couldn't you use a BNC-T to connect two multicouplers together?

 

[cg]

You can use those things if all your signals are strong. They provide no signal amplification to overcome the loss of splitting the original signal.

Odd that this post was bumped after several years, as this came up in the last month or so in a recent conversation with one of the techs at Stridsberg. If you are going to cascade multicouplers, connect each secondary one to the primary one. That way each gets the best signal from the primary unit. So the way it was described in the original post is the recommended way, rather than hooking a 4 port to an 8 port to a 4 port etc.

chris

 

[N9JIG]

Now that I am in my new home I have downsized to "only" 16 scanners plus an AR-DV1 and an R8500. While I am currently using 2 8-port and 1 4-port Stridsberg, each fed by an AntennaCraft ST2 in the attic I am thinking of using a single antenna with either a 16 or 32-port multicoupler tied to a decent amp. I live pretty far out in the hills but with limited antenna capabilities I have to be creative.

I might experiment again with stacking the 2 Stridsbergs, possibly on top of the WinGard TV amp when I have time.

 

[blantonl]

In my setup in San Antonio I've daisy chained two 8 port Stridsbergs - the "primary" serves 7 high-end communications receivers, and the secondary one is for less important scanners, feeds, etc