VHF - AIS antenna splitter ??

Bilgediver said:
MY Singapore translation says Cable divides into two. I would not use a transmitter with this device.
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Interesting ..... my Shanghai guys say one thing .... your Spore says another ....

I would ask my Spore office - but they are all Indian Singaporeans .....

Anyway .... until I get info that actually says what it can do ... it will stay in the box.
 
Refueler said:
Interesting ..... my Shanghai guys say one thing .... your Spore says another ....

I would ask my Spore office - but they are all Indian Singaporeans .....

Anyway .... until I get info that actually says what it can do ... it will stay in the box.
Click to expand...
I think part of the linguistic problem is that Chinese is far less precise than English. For example, we regard jade as being one of two specific minerals (jadeite and nephrite). But to Chinese, jade is a material with a particular appearance. So we get upset when green agate is sold as jade - but to Chinese, it is jade, though of a different quality. Similarly silk - to Chinese, labelling rayon as silk is ok, because as far as they're concerned, it looks like silk so it is silk.
 
I really don't understand the need to put an AIS antenna at the masthead. Range is good enough with it quite a bit lower. I don't like them on the rail transmitting directly at you. but mounted above a bimini seems fine. My own plan for when I installed AIS was the same as my active radar reflector, which I mounted on a pole fixed to the pushpit so that it was about 8 feet above deck level.
 
Refueler said:
Interesting ..... my Shanghai guys say one thing .... your Spore says another ....

I would ask my Spore office - but they are all Indian Singaporeans .....

Anyway .... until I get info that actually says what it can do ... it will stay in the box.
Click to expand...
Will the bottom plate come off so you can see inside? A picture may give some pointers
 
Hello Nigel. Sorry to hear you are not mobile. Get well soon. Don't expect any info from seller of device. he is almost certainly some retailer whose only info is a sales blurb from his supplier. As said don't use it with a transmitter.
You might like to try opening it up and post a picture of innards. Most likely just resistive splitter much like that used for connecting several TV receivers to one antenna.
If it were any more sophisticated it would claim it on box or sales blurb.
If you have doubts about rail mounted AIS antenna then connect it to VHF transceiver and see how range is. Should work ok but not as far as mast top antenna. If it is bad in any way it will show up and explain disappointing AIS range. ol'will
 
The back can be removed ... simply screwed in place. I will 'hobble' my way to tool box later today for screwdriver.

As to seller ... even my Shanghai guys say info from them is unlikely.

The rail mounted antenna is working fine - I just decided that I would prefer to 'split' the masthead antenna for maximum range.

Interesting question : What use would a 136 to 174Mhz receive only splitter be ? There are page after page online of sellers so there must be a reasonably common use for it ? The connectors are not 'broadcast receiver' style ... but full on screw PL259
 
OK ... seller replied :

New message from: jingcairensheng (18,211YELLOW_SHOOTING_STAR Star)
hello dear friend,

thanks for your question.

this item is for 1 radio (repeater) to connect 2 antennas.

please don't use this item on 2 radios to connect 1 antenna.

I hope you can understand.
thanks.

So that's it .... I have a box that will now go on the shelf ....
 
Interesting question : What use would a 136 to 174Mhz receive only splitter be ? There are page after page online of sellers so there must be a reasonably common use for it ? The connectors are not 'broadcast receiver' style ... but full on screw PL259
[/QUOTE]

repeaters will often use multiple antenna in an array, they can use sepearte radios for receive and transmit and the transmit be completely different frequencies which use separate antenn, this appears to be what this is for.
the connections are N type
 
Refueler said:
hello dear friend,

thanks for your question.

this item is for 1 radio (repeater) to connect 2 antennas.

please don't use this item on 2 radios to connect 1 antenna.

I hope you can understand.
thanks.
​

So that's it .... I have a box that will now go on the shelf ....
Click to expand...

Yes In that application it is a single radio connected to the single connection and the radio is operating in duplex mode on two different frequencies so two different antennas . This gives best performance if there is wide separation between input and output frequencies but not what you want.
 
Moonraker CS201 2-Way Aerial Antenna Coax Switch 5060080571321 | eBay

That is correct as it selects one radio or another so the unselected radio cannot fry the selected . Absolutely no use for our application where we require two radios to be able to linked to one antenna at the same time .where the device requires a few electronic components to detect when RF is present and sort tings out.
 
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Bilgediver said:
Moonraker CS201 2-Way Aerial Antenna Coax Switch 5060080571321 | eBay

That is correct as it selects one radio or another so the unselected radio cannot fry the selected . Absolutely no use for our application where we require two radios to be able to linked to one antenna at the same time .where the device requires a few electronic components to detect when RF is present and sort tings out.
Click to expand...

With a manual switch ... so imagine switched so AIS is sending out / receiving ..... and then someone forgets to switch over and keys the mic ??? 25W ...... pity that poor radio even if grounded.

Also - how are you going to hear 'ol Joe' calling you on VHF it all switched to AIS ??
 
Refueler said:
OK ... seller replied :

​
New message from: jingcairensheng (18,211YELLOW_SHOOTING_STAR Star)
hello dear friend,

thanks for your question.

this item is for 1 radio (repeater) to connect 2 antennas.

please don't use this item on 2 radios to connect 1 antenna.

I hope you can understand.
thanks.


So that's it .... I have a box that will now go on the shelf ....
Click to expand...
Back to my comment that seller has no idea what he is selling. It is not common to connect 2 antenna to 1 receiver unless as said you want different band antennae. 2 radios receivers to one antenna perhaps. Why "Repeater" I do not know. I don't beleive it wopuild handle any sort of transmission. Send it back to him or give a bad review of seller and item. ol'will
 
Its possible I will be testing a unit designed for the job later .... have spoken to a registered dealer for a unit. It is a passive unit though, but designed for Transponder AIS + VHF

Installation and test will have to wait till I am fully mobile.

At present with stern rail mounted AIS antenna ... I can pick up 2 or 3 boats in the harbour. Port workboats and odd fishing boat docked. My antenna is shielded by river bank and houses. Distance to targets about 1.5nm. I do not receive any targets from anchorage or main docks.

NP2WGa0.jpg


If I install splitter - then antenna will be ~8m higher and then I will see difference. Its possible that my location and its physical factors could be better test than out on Baltic .. because it will not be subject to sea state etc.
Pal has his boat with AIS in the yacht club ... in outer harbour. He cannot see my boat, I cannot see his on our displays. Once splitter installed - will be interesting to see if any change.
 
I have a splitter on my Class B AIS and VHF (its a Digital Yacht one - if you take a look online you can see a world of difference between it and the passive device in question). I get around 20nm range on AIS targets in open water - antenna base is 17m above sea level - but I would expect much less range in an area as cluttered as your mooring. I can't see how any passive unit would work switching between AIS and radio - a passive unit is just a splitter that shares signals between devices rather than one that actively switches between them.
 
Have you tried your current mast head vhf just with your AIS? this would confirm your thoughts regarding the possible range and additional targets you can see and give you something to compare with. I had a club member who was convinced his range was poor, when looked into this in more detail he was comparing what he saw from the boat to what he saw on marine traffic, he did not get that this is not a possible comparison
 
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