TSB240
Well-known member
Can anyone recommend a quality VHF splitter suitable for using with my Onwa Ais Transeiver. I understand the use and range limitations of a rail mounted antenna and just want some real user feedback on splitters.
VHF splltter recommendation.
- Thread starter TSB240
- Start date
Baggywrinkle
Well-known member
I'd like some real-world splitter experiences too 
Refueler
Well-known member
There are two versions :
Passive (non powered)
Active (powered)
I have the Onwa Passive Splitter with my KP39A Plotter along with the VHF radio .....
I'd have to search back posts of quite a while back - but the numbers are in region of :
Stern rail mounted antenna - just Plotter - no splitter : about 5 - 6 targets rec'd. With splitter and VHF ... similar number.
Mast head antenna - just plotter - no splitter - about 15 - 16 targets rec'd. With splitter and VHF ... about 12 - 15 targets rec'd.
The reduction is distance .. as the splitter does not amplify or assist received signal strength. But the reception distnace is well over what I term 'required' distance.
I have no numbers for Active splitter - but would assume the masthead results to be in the 15 - 16 rec'd range ... basically making up for any losses in reception.
Some people think Active boosts transmission .. as I understand it - that is not the case. The boost is in reception of AIS signals and has no effect on transmitted AIS and VHF.
I ma happy enough with the Passive splitter ... but I can understand many would prefer Active to gain maximum performance.
One word of caution : IF you choose a Passive Splitter - do not buy a no-name splitter ... buy only a Brand name - such as Onwa / Matsutech etc.
The no-name splitters - many are not capable of surviving the VHF 25W output. But brand name are proper boards that separate the two ...
Here's example no-name from eBay advertised as a splitter alongside my Onwa :
Here is inside that PoS :
Here is inside the Onwa which works perfectly :
Shot of plotter screen :
21 targets !
So : If you want max distance - go Active powered Splitter. If like me 15nm or more is good enough reception - Passive non-powered is good enough.
Costs are of course significantly different between them ....
Passive (non powered)
Active (powered)
I have the Onwa Passive Splitter with my KP39A Plotter along with the VHF radio .....
I'd have to search back posts of quite a while back - but the numbers are in region of :
Stern rail mounted antenna - just Plotter - no splitter : about 5 - 6 targets rec'd. With splitter and VHF ... similar number.
Mast head antenna - just plotter - no splitter - about 15 - 16 targets rec'd. With splitter and VHF ... about 12 - 15 targets rec'd.
The reduction is distance .. as the splitter does not amplify or assist received signal strength. But the reception distnace is well over what I term 'required' distance.
I have no numbers for Active splitter - but would assume the masthead results to be in the 15 - 16 rec'd range ... basically making up for any losses in reception.
Some people think Active boosts transmission .. as I understand it - that is not the case. The boost is in reception of AIS signals and has no effect on transmitted AIS and VHF.
I ma happy enough with the Passive splitter ... but I can understand many would prefer Active to gain maximum performance.
One word of caution : IF you choose a Passive Splitter - do not buy a no-name splitter ... buy only a Brand name - such as Onwa / Matsutech etc.
The no-name splitters - many are not capable of surviving the VHF 25W output. But brand name are proper boards that separate the two ...
Here's example no-name from eBay advertised as a splitter alongside my Onwa :
Here is inside that PoS :
Here is inside the Onwa which works perfectly :
Shot of plotter screen :
21 targets !
So : If you want max distance - go Active powered Splitter. If like me 15nm or more is good enough reception - Passive non-powered is good enough.
Costs are of course significantly different between them ....
oldgit
Well-known member
Digital Yacht splitter on my boat. It failed . £250 .00.
Replaced with a basic budget vhf antenna dedicated to AIS , worked just as well and simple to install. £50.00.
Replaced with a basic budget vhf antenna dedicated to AIS , worked just as well and simple to install. £50.00.
Refueler
Well-known member
Many people give up height of antenna for simple install ... plus of course many Mobo's cannot get as high as a sail boat can.
I used to have AIS Receive on the transom rail ... never really liked it there .. the difference in performance from masthead is huge.
To install two antenna - problem is separation distance needed between them ... even on spreaders - its not enough.
The passive Splitter I have with masthead antenna - far outperforms any rail mounted single dedicated antenna ..
I used to have AIS Receive on the transom rail ... never really liked it there .. the difference in performance from masthead is huge.
To install two antenna - problem is separation distance needed between them ... even on spreaders - its not enough.
The passive Splitter I have with masthead antenna - far outperforms any rail mounted single dedicated antenna ..
Momac
Well-known member
For my motorboat I found it more economical, when fitting AIS a few years ago, to have a separate antenna for the AIS.
I haven't really thought about range but I do know VTS are able see me okay and I haven't noticed any issues seeing ships on the display.
I haven't really thought about range but I do know VTS are able see me okay and I haven't noticed any issues seeing ships on the display.
st599
Well-known member
Transom rail gives you a second option in an emergency.
Beware cheap splitters, I measured a few with 4dB plus insertion loss. And always have a patch lead to hand to bypass.
Beware cheap splitters, I measured a few with 4dB plus insertion loss. And always have a patch lead to hand to bypass.
Bilgediver
Well-known member
Beware...Many splitters will protect your AIS from VHF transmissions however very few will also protect your VHF. from AIS transmissions as they are designed for receive only AIS. Make sure you only get one that suites your installation or you may blow your VHF .
TSB240
Well-known member
Thanks for the contributions so far.
Still hoping for more real user feedback on splitters.
I have used a rail mount in the past and this gave variable results.
RANGE visibility to other boats and shore stations was more restricted due to line of sight blocking by natural features or rougher sea conditions.
This was more obvious when cruising in company with other boats fitted with low level mounted AIS Transmitters.
I have an older Icom VHF with add on DSC unit that uses both a Mast head Antenna for VHF Transmit and a separate rail mount antenna for DSC .
I really don't want another less effective AIS antenna at low level and am only interested in using a quality splitter to the mast head.
Still hoping for more real user feedback on splitters.
I have used a rail mount in the past and this gave variable results.
RANGE visibility to other boats and shore stations was more restricted due to line of sight blocking by natural features or rougher sea conditions.
This was more obvious when cruising in company with other boats fitted with low level mounted AIS Transmitters.
I have an older Icom VHF with add on DSC unit that uses both a Mast head Antenna for VHF Transmit and a separate rail mount antenna for DSC .
I really don't want another less effective AIS antenna at low level and am only interested in using a quality splitter to the mast head.
PaulRainbow
Well-known member
You have an Onwa AIS, so why not just use their splitter ?
Refueler
Well-known member
Sorry but that's misleading and basically not fully correct.
Yes VHF can blow AIS if bad splitter .. but AIS for a yacht is low power ...
Second Splitters are easily checked by reading the specs to ensure two way signals ...
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Refueler
Well-known member
I have the Onwa Splitter ... its passive non powered .. works well. I was sent it by Alan at Aves marine to test and report back .. both of us were pleasantly surprised at its performance.
There's also the Matsutech - basically same item ..
I would always advise the Active Powered Splitter - if wallet can open to that sort of money ... but if a masthead / high level antenna is installed - the Passive will do a good job. Splitters don't actually care what brand is connected ..
Refueler
Well-known member
OK - Bit of info :
Many VHF's today have self diagnostics .. you scroll through menu and you can initiate diagnostics to make sure antenna + cable are good .... microphone good ... RF section etc etc ...
But if you fit a Splitter - the antenna diagnostics will return ERROR ... basically because the Splitter is open till a Tx signal hits it.
Also SWR meter will not give results .. in fact near all test gear will show error.
Many VHF's today have self diagnostics .. you scroll through menu and you can initiate diagnostics to make sure antenna + cable are good .... microphone good ... RF section etc etc ...
But if you fit a Splitter - the antenna diagnostics will return ERROR ... basically because the Splitter is open till a Tx signal hits it.
Also SWR meter will not give results .. in fact near all test gear will show error.
Refueler
Well-known member
Blimey - is my info not from REAL user ??
To put it simply :
You could get the Passive Splitter from ONWA / Matsutech and have good performance. Cost is about 100 quid I think.
You could spend a lot more and get the boosted Active Splitter that will possibly increase the range you can detect other AIS .. think cheapest is about 250 quid ??
What other info do you need ??
onesea
Well-known member
Cannot do comparison however, faced with same problem I went with:
QK-A015-TX Active VHF Splitter (for AIS transponders)
Looked best value at the time, I have had no problems with it.
The advantage of indicator light a number means I know if it’s transmitting crude VHF/ AIS test. When the coastguard announces an open mic, a check on lights confirms it’s not you. It says it fails to VHF if no power.
Cannot give range regarding targets other than to say far enough that I have never been waiting for target to appear on AIS they have always been there first or not at all.
QK-A015-TX Active VHF Splitter (for AIS transponders)
Looked best value at the time, I have had no problems with it.
The advantage of indicator light a number means I know if it’s transmitting crude VHF/ AIS test. When the coastguard announces an open mic, a check on lights confirms it’s not you. It says it fails to VHF if no power.
Cannot give range regarding targets other than to say far enough that I have never been waiting for target to appear on AIS they have always been there first or not at all.
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Refueler
Well-known member
Here's my follow up thread on the ONWA splitter I tested and still have fitted ....
Follow on from my VHF - AIS Splitter thread recently >>
Follow on from my VHF - AIS Splitter thread recently >>
Refueler
Well-known member
That's a good device - BUT not suitable for OP as he has an ONWA Plotter with AIS transmit and receive.
Your Quark is AIS Receive only.
TBH - I would not advise buying a Receive only unit - it means that later if you want to have AIS Trx - you need replace the unit.
MattS
Active member
I installed this Quark-Elec Active Splitter for AIS Transponders - QK-A015-TX Active VHF Splitter (for AIS transponders)
Share my masthead antenna between my VHF radio and my Ocean Signal ATB1 transponder.
As @Refueler mentioned, my SWR meter will not give me a reading through the splitter so I haven't been able to measure the SWR value with the splitter in the chain.
However I regularly ask National Coastwatch Institute stations for AIS and VHF checks at varying distances out so try and gauge how it is working, and it seems to be doing a good job - distances are acceptable.
Additionally, my Ocean Signal ATB1 sometimes shows that there is a SWR error on the line. I spoke to Ocean Signal who advised that it could be that the SWR threshold is just a little sensitive, and offered to do me a custom firmware to increase it. But equally it could the same diagnostics issue - that when the ATB1 attempts to do an SWR check it is getting no response via the splitter.
Share my masthead antenna between my VHF radio and my Ocean Signal ATB1 transponder.
As @Refueler mentioned, my SWR meter will not give me a reading through the splitter so I haven't been able to measure the SWR value with the splitter in the chain.
However I regularly ask National Coastwatch Institute stations for AIS and VHF checks at varying distances out so try and gauge how it is working, and it seems to be doing a good job - distances are acceptable.
Additionally, my Ocean Signal ATB1 sometimes shows that there is a SWR error on the line. I spoke to Ocean Signal who advised that it could be that the SWR threshold is just a little sensitive, and offered to do me a custom firmware to increase it. But equally it could the same diagnostics issue - that when the ATB1 attempts to do an SWR check it is getting no response via the splitter.
Refueler
Well-known member
The last few posts have shown the care needed in choosing the Splitter ... CHECK FULLY the specs of the item chosen. The posts both quote Auark A015 ... but only "MattS" unit is Transponder ... "onesea" is AIS receive only.
Some are only AIS Receive ............ this is with Active units as I understand it ... where the circuitry used is only boosting AIS receive and has no through switching for AIS transmit.
Some are only AIS Receive ............ this is with Active units as I understand it ... where the circuitry used is only boosting AIS receive and has no through switching for AIS transmit.
onesea
Well-known member
Updated original post with correct device:
QK-A015-TX Active VHF Splitter (for AIS transponders)
Thanks for correcting me, I guess they have gone up in price since I bought. I seem to remember paying less
As you rightfully point take care when buying, when I priced up I had to double check it’s not always as clear as you would think.
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