VHF/AIS splitter problems....

[Carolwildbird]

Last year I installed an easysplit antennae splitter and easyAIS together with NMEA multiplexer. All working fine- AIS on raymarine c120 plotter, VHF all ok.

I've just installed a new VHF radio (standard horizon GX1500E), and all seemed to be well - AIS received OK, VHF received OK. Arrived in Fowey and tried to call the harbour taxi on low power only to get horrible fast clicking from the splitter box, and no transmission. Ok on high power.

So far-

Tried connecting VHF radio to emergency VHF aeriel- no problem with transmitting on low and high power

Tested/checked all connections from masthead to VHF- no apprent problems

Bypassed splitter and connected VHF radio to masthead aeriel- no problems.

So concluded it was the easysplit spliiter.

Bought new one- installed today - arghhhh- still same symptoms- fast clicking on low power, though AIS reception Ok, and high power TX OK.

Checked power supply- all OK.

MES (suppliers) are talking to easysplit and standard horizon to see if there is any incompatibility problem.

Any suggestions? Its foxing me...

Carol

 

[William_H]

Almost certainly the design of the splitter requires a certain amount of Radio power to tell it to go to transmit mode and with your new transmitter in low power mode it is not enough to activate the splitter.

You can either not use low power mode or fit another antenna for AIS and don't use a splitter. good luck olewill

 

[ianat182]

Don't know anything about AIS, but I get a repetitive clicking on my PC whenever I am within 3ft range with my mobile phone switched on standby, could this be possible cause?
ianat182

 

[Oldhand]

I have expereinced this problem but it disappeared when I changed the RF cable between the splitter and the VHF to one of different length. The problem seemed to be frequency related but one wouldn't expect enough mismatch at the cable and unit connectors to cause a reflection resonanace. Anyway I suggest you try another cable of a different length.

 

[ccscott49]

Use the VHF only on high power, simples!

Check your cable connections from VHF to splitter, maybe some power loss there, because I think that is what it is, power from VHF on low power is inadequate to switch the splitter over.
If you have a spare jumper cable, try that.

As an aside, I dont like these "splitters", they have a propensity to failure and I dont want my primary source of marine coimunication/distress through one.
I would get another antenna and have them seperate, which is exactly what I have done.

 

[Carolwildbird]

Thanks peeps!

It seems a concensus that the power from the vhf is inadequate to switch the splitter over. Damn. It worked fine with my old radio-- and works fine for AIS and high power vhf mode. Ah well.

I'm going to show my ignorance now- what's a jumper cable?

I will have to investigate a separate antenna, I guess.

 

[PaulBigwood]

The Easysplit specification shows 400mW as the minimum RF needed to switch the aerial.

The GX1500E Low Power setting is 1W, so some of your precious low power RF is being used to energise the switching relay.

If the cable between the radio and the EasySplit is not very good or the connections are a bit suspect, then the VSWR (Standing Wave Ratio) on the cable will not be 1:1 and so some of the power will be reflected back up the cable. The end result is not enough power actually getting to the EasySplit to engergise the relay.

I would recommend what others have said, use high power or use a seperate aerial for the AIS. You could mount a pair of small diodes back to back across the AIS receiver aerial to short excess power received on the aerial when transmitting on the VHF.

Paul