Stridsberg Multicouplers?

[iMONITOR]

Stridsberg Multicouplers?


MCA 780M vs. MC204M

Multicouplers

The MCA780M is designed for 700/800 MHz, the MCA204M is designed for 25 MHz to 1GHz. So it appears that the MCA204 pretty much covers all normal scanner frequency ranges where as the MCA780M does not. If your purpose falls within 700-800 MHz would there be any disadvantage to using the MCA204M over the MCA780M?

 

[GTR8000]

As with any wideband device, there is a potential disadvantage to using the 204M if you have strong nearby signals in the VHF and/or UHF band that overload your receivers. If you only need 700/800 coverage and will never stray out of that band, then the 780M gives you some built-in attenuation/filtering of those out of band signals.

 

[900mhz]

Just to give you an idea on how tight the MCA780M is, I tried to pass some 935 MHz trunking through it, just to see. No dice. It definitely offers out of band filtering.

 

[jonwienke]

It all depends on the odds of ever needing to monitor frequencies outside the 780M's range vs the odds of an out-of band signal overloading the 204M's amplifier. I listen to more than 7/800, so the 780M is not an option for me.

 

[iMONITOR]

It all depends on the odds of ever needing to monitor frequencies outside the 780M's range vs the odds of an out-of band signal overloading the 204M's amplifier. I listen to more than 7/800, so the 780M is not an option for me.

I do have two BCD536HP's dedicated to monitoring Michigan's very large MPSCS P25 digital system. That system goes deep down into the 700 MHz band as well as fairly high up into the 800 MHz band so I certainly don't want any filters clipping of anything within them and I don't have a need to filter anything above or below those bands. But I don't expect to go below or above those bands, I have two other radios for that.

I don't require any amplification of those signals for now. I'm currently using a MC202 two port 'passive' coupler that works perfectly with full signal bars on both scanners. I'm considering adding a third scanner to the MPSCS bands and that is why I'm anticipating the need for a pre-amplified multicoupler with three scanners along with cables and fittings. Stridsberg does make a 4-port passive coupler but I'm not sure if I'd get away with it.

 

[Ubbe]

I'm currently using a MC202 two port 'passive' coupler that works perfectly with full signal bars on both scanners.... Stridsberg does make a 4-port passive coupler but I'm not sure if I'd get away with it.

Stridsbergs passive all-band couplers have the exact same specifications as a $10 CATV splitter when it comes to isolation between ports and total loss. 50 or 75 ohm doesn't matter and get coaxes with F connectors at one end.

A 2 port splitter has something like a 3,5dB attenuation and a 3 port has 6,5dB and that 3dB difference should equal to one signal bar.
If you have full signal strenght using a 2 port splitter it should also work with a 3 port. It's a $8,50 cost to try, not including the cables.

https://www.amazon.com/5-2300-Coaxial-Antenna-Splitter-Satellite/dp/B07FDQR5HN/

Get a $8 4-pack of adapters just as a test.

https://www.amazon.com/CIMPLE-CO-Coaxial-Connector-Converter/dp/B07NJ8Z4RR/

/Ubbe

 

[GTR8000]

A 2 port splitter has something like a 3,5dB attenuation and a 3 port has 6,5dB

A 3-port balanced 75 ohm splitter has -5.5 dB of loss on each port. Unbalanced 3-port 75 ohm splitters are also very common, having 1 port with -3.5 dB of loss, and the other 2 ports with -7.5 dB of loss.

 

[iMONITOR]

Below are the specs on the Stridsberg MC202 passive 2-port coupler. I don't fully understand the highlighted specs. How might they compare to the TV couplers? Do the BNC/F adapters introduce additional loss?

MC202
Nominal Impedance: 50 ohm
Port-To-Port isolation (min): 22 dB
Return Loss (all ports): > 20 dB
Phase (input/Output): 0 degrees
Insertion Loss (Total): 2-Port = 4 dB, 4-port = 7 dB (+ 0 / -1,5 dB)

 

[Ubbe]

The splitter I linked to have no spec, but for a CATV splitter from TRIAX, a danish company that I use a lot, they specify:
Nominal Impedance: 75 ohm

Port-To-Port isolation
5 - 40 MHz 30 dB
40 - 470 MHz 32 dB
470 - 860 MHz 28 dB
860 - 1000 MHz 28 dB

Return Loss (all ports):
5-40 MHz 22 dB
40-470 MHz 21 dB
470-860 MHz 21 dB
860-1000 MHz 20 dB


Insertion Loss 2-Port:
5-40 MHz 3.5 dB
40-470 MHz 3.6 dB
470-860 MHz 3.6 dB
860-1000 MHz 4.0 dB

Insertion Loss 3-Port:
5-40 MHz 6.0 dB
40-470 MHz 5.8 dB
470-860 MHz 6.5 dB
860-1000 MHz 6.5 dB

Insertion Loss 4-Port:
5-40 MHz 7.0 dB
40-470 MHz 7.5 dB
470-860 MHz 8.2 dB
860-1000 MHz 8.2 dB

They are pretty much equal in specs and adapters should never have any loss, or less than 0,1dB. But they can be mechanical bad so if they are pushed to the side they could give a bad connection. The cheap chinese ones I buy in 10-pack usually have 1 or 2 that are bad so I have to test each one using a constant weak signal, in analog mode with a scanner to be able to hear when the signal level changes, and discard any connectors that show the slightest problem. If you buy well known branded connectors at 10 times the cost they never show any problems.

/Ubbe