Connecting multiple digital scanners to the same scanner antenna.

[Wlbrant]

I have the BCD996P2 and the BCD996XT connected togather with bnc "t" connectors thru rg6 coax to a single antenna. Both scanners seam to receive well. When I try to connect a third scanner a BCD996P2 into the loop I loose signal strength. Has anyone ran into this problem? It is not a cable issue as I made a new cable with new ends. Thought about putting a signal amp into the works, however I have a new antenna I am planning on raising for the P2 scanners. Any suggestions?

 

[jonwienke]

You can get away with running 2 scanners on one antenna using just a T without too much loss. But more than that and the loss starts killing reception.

 

[ka3aaa]

you are going to need a signal splitter like they use on tv antennsa.

 

[jonwienke]

A good 3-way splitter still has 5-6dB of loss, unless you amplify before the splitter. Enough to notice the decrease in reception compared to a direct connection.

 

[chief21]

The correct way to connect multiple receivers to a single antenna is by the use of a receiver multicoupler, such as those made by Stridsberg Engineering. Wide-band television distribution amplifiers could also be used, but may not be as "clean" as a purpose-built device.

 

[Ubbe]

Depending of the filter design in a scanner it could either be more or less short circuit or open circuit at other frequencies than the filter is made for, that will make the coax between two scanners work as a stub filter attenuating certain frequencies.

If one scanner monitors 150MHz and the other 800MHz you will get this problem. If all scanners are on the same frequency band then they have more or less the same impedance and will work better although the signal level will be attenuated some, as the signal has to be split up to the different scanners.

Try to alter the lenght of the coax going to the third scanner that made you loose the signal. Try 50% longer or shorter. It's usually easier to add another coax to the first one to increase the lenght. It could take several tries to get a lenght that works for the frequencies you monitor.

Using a real splitter, like a CATV type, will attenuate the negative effects from the coax strub filter problem up to 100 times but will still attenuate the recieved signal something like 5 times. A tv or sat splitter with an amplifier will improve the signal and reduce the problems, even a cheap one will work if you can reduce its gain down to 10dB or lower. The prefered solution would be to put a quality low noise amplifier at the antenna and then have the CATV splitter at the scanners. An attenuator probably have to be used before the splitter to reduce the signal level by 10-15dB or the scanner will receive too much signal and you will instead receive interferencies and ghost frequencies.

/Ubbe

 

[MisterLongwire]

No need to alter your length of coax and DO NOT BOTHER using a TV/cable splitter either. Total garbage! Do it the right way and get a receiver multicoupler, such as those made by Stridsberg Engineering as mentioned by CHIEF21. There will be no loss and as mentioned if you use a reg amp to a regular splitter the signal will be sounding trashy. If you use a regular TV splitter you can notice a loss in signal whether your 2 radios are on the same frequency or not. It will be noticeable.

 

[iMONITOR]

STRIDSBERG MULTICOUPLERS

Multicouplers

The have a 2, 4 and 8 port version. The cost difference between the 2 & 4 port version is very little, makes more sense to get the 4 port for possible future needs. They also have a passive (non-amplified) version and a active (amplified) version. Get the amplified version even if you have good signal levels as the amp will help make up for cable/connector losses. I use the MCA204M for VHF/UHF air bands , works great!

 

[MTScannerNut]

STRIDSBERG MULTICOUPLERS

Multicouplers

The have a 2, 4 and 8 port version. The cost difference between the 2 & 4 port version is very little, makes more sense to get the 4 port for possible future needs. They also have a passive (non-amplified) version and a active (amplified) version. Get the amplified version even if you have good signal levels as the amp will help make up for cable/connector losses. I use the MCA204M for VHF/UHF air bands , works great!

View attachment 75969

I've always wondered when using an amplified multicoupler like the Stridsberg, does it increase noise/static to each receiver? Or is it really like having two separate antennas?

 

[jonwienke]

Any amplifier will increase noise slightly. With a good unit like the Stridsberg, it won't be noticeable unless you are measuring with lab equipment.

 

[iMONITOR]

I've always wondered when using an amplified multicoupler like the Stridsberg, does it increase noise/static to each receiver? Or is it really like having two separate antennas?

I find it better than two separate antennas as the preamp gives the signal a noticeable boost without any noticeable increase in noise...other than what I hear from the wife!

 

[tvengr]

I have 2 of them. No signal loss and frequency response 25-1,000 MHz. Also work mobile on 12v.

 

[XPS720]

My first outside antenna will go up this week and yes I need a good 4 way port. I use 3 scanners all the time, AOR 8600 K2, BCD536HP and SDS2300. I only turn on my ICOM IC-R75 for weekend ham DX'ing. My new antenna cover all area's on my rigs. So I ask for a good 4 way.

Thank you,

73's

 

[jonwienke]

Multicouplers

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

Note that it is for RX only. If you want to TX, you'll need to do it on a separate antenna.

 

[buddrousa]

My set up 1 ST2 next 1 4 port Stridsberg feeding 2 8 port stridsbergs each feeding 8 scanners and the 2 spare ports on the 4 port feeds my work bench.

my shack 2.jpg

on top 15's next 536's and SDS200 in the middle and my 6 996P2's on bottem

forums.radioreference.com

my shack 6.jpg

My 16 Unidens with PROSCAN on 1 PC

forums.radioreference.com

 

[trentbob]

All of the advice here is sound, Sage advice.

Budd, I have always admired your set up. Most impressive!

I know I'm an oddball but I actually have three lines of lmr400 coming in, one coax from each one of my three antennas that are located in different parts of my roof.

I like the different positions and type of antennas to give me the latitude to use one antenna over the other for certain applications and I've been able to ascertain which antenna works best for different applications.

To the o p, even though you are using a two-way splitter for one antenna and it doesn't seem like you have much loss, you do, not much, but you do.

This is a good thread with a lot of good information.

 

[XPS720]

Multicouplers

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

Note that it is for RX only. If you want to TX, you'll need to do it on a separate antenna.

Thank you but I am only a DX'er. Hopefully, at age 66, I can learn CW to get my licence.

 

[XPS720]

To me it looks like the
MCA204M
VHF/UHF Receiver Multicoupler - 25 MHz to 1 GHz - 4-ports for what I want to do. I hope the MW will work also.

Thank you,

 

[XPS720]

My set up 1 ST2 next 1 4 port Stridsberg feeding 2 8 port stridsbergs each feeding 8 scanners and the 2 spare ports on the 4 port feeds my work bench.

my shack 2.jpg

on top 15's next 536's and SDS200 in the middle and my 6 996P2's on bottem

forums.radioreference.com

my shack 6.jpg

My 16 Unidens with PROSCAN on 1 PC

forums.radioreference.com

Of all your rigs, what machine, if you can only keep 1 would you keep?

 

[buddrousa]

Either my 200 or 536 both are equal as I have no simulcast systems in my area and I have a mix or p25 p1 and p2 nxdn and dmr