Stridsbery Multicoupler

[ffighter17]

I am using a MCA204M 4 port multicouple on a SDS100 and a 996XT, I primarily listen to VHF P25. I have one UHF 462.950 I listen to for EMS/Fire paging. I am running a Watson WBV-60 Wideband Base Antenna with LMR400 in the attic. I can hear systems 50ish miles away, I am having 2 issues.

1. The UHF frequency comes in really strong sometimes and is very scratchy most of the time. I can hit the repeater from my house with a handheld radio and reception is pretty good. This is occurring on my SDS 100 and 996XT

2. I have VHF P25 monitoring 2 frequencies all of the time on the 996XT, when either of the frequencies are keyed up and the 996XT is receiving my sds100 goes deaf. The 2 frequencies I have in the 996XT are not monitored by the sds100 all of the time. If i do have the sds100 on the 2 vhf p25 it comes in full strength. The 2 VHF P25 frequencies I monitor on the 996XT are my local city and the water tower with frequencies is about a mile from my house and the dispatch center is about 3 blocks from me.
Can someone shed some light on what might be going on and it the multicoupler maybe my issue. I know the UHF system has had some changes made to it the within the last several months when it use to come in clear all the time. I dont remember on the VHF frequencies if this has always occurred.

Thanks for the info

 

[Ubbe]

1. It could have happened something with the multicoupler. Try and connect the antenna coax directly to the 996 and compare.

2. The 996 have a much better receiver than the SDS100. There is a IFX feature that might make a change. Stop scan and push function and then 7. There are also different filters for conventional departments and trunked sites that you can try with different settings like Invert and Wide Normal and the rest of them. If signals are very strong they could be too strong for the SDS100 so try also the attenuator setting, stop scan and do function and then 4.

/Ubbe

 

[prcguy]

I would test with just one scanner connected to the antenna with no multicoupler and see if you have the same problem. If the problem persists the amplifier in the multicoupler could be overloading and creating IMD. If so you might be able to find the offending strong signals like paging or FM broadcast and get a notch filter.