Multi Coupler for my Discone Antenna

[02blackss]

Anyone looking for a Multi Coupler , this is the place. US military grade apparently. I just ordered one now from here.

Receiver Multicouplers, Passive and Active, HF to VHF/UHF

I got the MCA204M/N

N connector input, 4 BNC outputs. No loss is claimed by the manufacturer.

I will be hooking up my 4 base units to that discone. It should be here in a week or so and I will review it.

Jason

 

[rivardj]

I have found the Channel Master CM3418 8-Port Distribution Amplifier is a good solution for feeding multiple scanners if you do not wish to monitor frequencies below 54 MHz. The price is right at around $45.00 even though F to BNC adapters or coaxial cable with the correct connectors on each end are required to complete the connections.

I have four Radio Shack scanners and two NooElec R820T USB sticks feed with this amp with great performance. The antenna is a multi-band home-brew ground plane.

Also remember to terminate any unused ports.

 

[02blackss]

Thanks for that info! Luckily for me, all 4 ports will be active!@

 

[n3ouc]

I just picked up the MCA204M/N and it is fantastic! Absolutely no loss at all on all four of my scanners and in fact I seem to have picked up a little gain even though the manufacture doesn't state that. It is pricey and maybe there is something just as good out there that is less costly, but I am one happy customer and I guess that counts for something.

Mike

 

[ATCTech]

I've had a 4 port and an 8 port for almost 3 years now. They are very well made pieces of hardware and John is terrific to talk to. They work as advertised, there, review done! <G>

For the chap that mentioned the use of a TV amplifier (and we've all tried that one time or another over the years, me included) I realize the cost differential is nearly 5:1 to the Stridsberg unit (or similar) but the performance difference, especially the noise factor and linear frequency response, is worth the price of admission alone.

 

[motomeso]

I'm using the same 8 port amplifier with great results running 6 scanners, a receive only CM200 and an RTL Dongle.

I have found the Channel Master CM3418 8-Port Distribution Amplifier is a good solution for feeding multiple scanners if you do not wish to monitor frequencies below 54 MHz. The price is right at around $45.00 even though F to BNC adapters or coaxial cable with the correct connectors on each end are required to complete the connections.

I have four Radio Shack scanners and two NooElec R820T USB sticks feed with this amp with great performance. The antenna is a multi-band home-brew ground plane.

Also remember to terminate any unused ports.

 

[rivardj]

I've had a 4 port and an 8 port for almost 3 years now. They are very well made pieces of hardware and John is terrific to talk to. They work as advertised, there, review done! <G>

For the chap that mentioned the use of a TV amplifier (and we've all tried that one time or another over the years, me included) I realize the cost differential is nearly 5:1 to the Stridsberg unit (or similar) but the performance difference, especially the noise factor and linear frequency response, is worth the price of admission alone.

I don't have any test equipment to verify the specs but this is what is claimed:


MCA204M VHF/UHF Receiver Multicoupler 25 MHz to 1 GHz 4 Ports Specifications:

Frequency Range: 25 MHz to 1 GHz
Isolation: > 22 dB (port-to-port)
Gain/Loss: +4 dB, +/- 1.5 dB (nom) (Unused ports terminated)
P1dB: +17 dBm (output)
OIP3: +31 dBm (output)
Return Loss: >18 dB (Input and Output ports, 50 terminated, power on)
Input Filter: 25 MHz High-Pass
Noise Figure: 3.5 dB (nominal/50 Ohm terminated)
RF Connectors: BNC
DC Connection: 5.5mm/2.1mm (coaxial)
DC Power: +12 VDC at 100 mA
Enclosure: Die Cast Aluminum
EMI/RFI Sheilding: 75 dB min. at 870 MHz
Size: 5.5 x 2.25 x 1.25 Inches
(excluding connectors)



Channel Master CM3418 8-Port Distribution Amplifier specifications:

Forward frequency range: 54 to 1002 MHz
Return path frequency range: 5 to 42 MHz
Gain: 4dB
Noise figure: typically less than 2dB
Isolation: 24 dB
Max output level: 14 dBmV
Passive return: -11.5 dB
Connector: F-type
Weight (packaging): 1.8 lb
Size (packaging): 5.8L x 2.3W x 8.5H in


If these specs are to be believed, and I think they are, the Channel Master CM3418 8-Port Distribution Amplifier is not a bad alternative. If one can live with the 54 MHz low end frequency limitation and having to use connector adapters, this distribution amp may be a solution for some especially considering the cost differential.

I think the stated noise floor spec for the Channel Master is within reason based on the results I see with squelch setting on my radios. I did not notice much if any increase in my squelch settings in order to quiet the radios. In the past I have had amatuer radio amplifiers with internal pre-amps that that required the radio's squelch to be increased dramatically when the pre-amp was activated to quiet the rig. Even considering the high gain of those pre-amps, the noise floor was horrid. I don't find that to be the case with the Channel Master.

 

[prcguy]

CATV amplifiers are designed to be used within a closed system with specific bands of TV signals at known levels and not intended to be connected to a wideband antenna.

Looking at just the maximum output specs the MCA204M is rated at 17dBm for P1, which is when its amplifier is at the 1dB compression point. The Channel Master CM3418 is rated at 14dBmV max output, which is around -35dBm and really, really lousy. Even if that spec is for an 80 channel TV system with all channels lit up that would put it in the -14dBm max output range which is still a really crappy spec.

Connect that to a wideband Discone in a major city and the amp will be generating so much IMD you'll hear FM radio stations, paging and cell phone calls in places where they don't belong.

There is a good reason a high quality communications multicoupler costs a lot of money and a CATV amp is cheap.
prcguy

I don't have any test equipment to verify the specs but this is what is claimed:


MCA204M VHF/UHF Receiver Multicoupler 25 MHz to 1 GHz 4 Ports Specifications:

Frequency Range: 25 MHz to 1 GHz
Isolation: > 22 dB (port-to-port)
Gain/Loss: +4 dB, +/- 1.5 dB (nom) (Unused ports terminated)
P1dB: +17 dBm (output)
OIP3: +31 dBm (output)
Return Loss: >18 dB (Input and Output ports, 50 terminated, power on)
Input Filter: 25 MHz High-Pass
Noise Figure: 3.5 dB (nominal/50 Ohm terminated)
RF Connectors: BNC
DC Connection: 5.5mm/2.1mm (coaxial)
DC Power: +12 VDC at 100 mA
Enclosure: Die Cast Aluminum
EMI/RFI Sheilding: 75 dB min. at 870 MHz
Size: 5.5 x 2.25 x 1.25 Inches
(excluding connectors)



Channel Master CM3418 8-Port Distribution Amplifier specifications:

Forward frequency range: 54 to 1002 MHz
Return path frequency range: 5 to 42 MHz
Gain: 4dB
Noise figure: typically less than 2dB
Isolation: 24 dB
Max output level: 14 dBmV
Passive return: -11.5 dB
Connector: F-type
Weight (packaging): 1.8 lb
Size (packaging): 5.8L x 2.3W x 8.5H in


If these specs are to be believed, and I think they are, the Channel Master CM3418 8-Port Distribution Amplifier is not a bad alternative. If one can live with the 54 MHz low end frequency limitation and having to use connector adapters, this distribution amp may be a solution for some especially considering the cost differential.

I think the stated noise floor spec for the Channel Master is within reason based on the results I see with squelch setting on my radios. I did not notice much if any increase in my squelch settings in order to quiet the radios. In the past I have had amatuer radio amplifiers with internal pre-amps that that required the radio's squelch to be increased dramatically when the pre-amp was activated to quiet the rig. Even considering the high gain of those pre-amps, the noise floor was horrid. I don't find that to be the case with the Channel Master.

 

[Turbo68]

Hi Jason been using 2 MCA204M 4 port multicouplers for years never had any problems with them antennas
are Icom-AH7000 discone,Polar-214A Airband and each one got 8 receivers hooked up to it there not cheap but do an excellent job also use there passive ones with excellent results.

Regards Lino.

 

[VE2XWA]

+1 for prcguy