Topics

Electronics


Bob Miller
 

John -


This is part cautionary tale about electronics creep and part informational. I was leaning towards joining you for your March 21 session. But since COVID-19 has now appeared in Jefferson County, I don’t want to chance inadvertently spreading contagion. 


My tale begins when I moved to an electric start outboard last year as a hedge against my inexorable side into geezerdom. Since I will be a support boat for this year’s Salish 100 and I now had the requisite battery system, I decided to put in a fixed VHF. My friend Simeon Baldwin offered me a new Shakespeare “Squatty Body” (VHF/AIS) antenna that didn’t fit his needs. So, I started thinking about real-time AIS. Navionics sent me a renewal notice in the fall and I saw that they had added AIS capability. So, the next step was a splitter and an AIS receiver. I got both for about $115. I now will be able to get real-time AIS on my iPad through Navionics, either wifi or USB connection (the receiver, about the size of 2 matchboxes, will be mounted in the cockpit near me). It’s a slippery slope….


Of course, AIS is not needed most places we take our boats but it’s definitely valuable up here. As well as the traffic lanes through the sound, we encounter large vessel traffic variously in Juan de Fuca, Rosario, and Haro straits in our cruising grounds. It would also be valuable on the Columbia.


Cheers,



johnacord
 

Bob,

That's a very good price for both.  Can you share with us where you got them?

On the big boat I had AIS that displayed on my PC charting program and found it quite valuable, especially in foggy SF Bay and the California coast.  On the little boat I still use the PC charting and after getting to know this area feel it would be a very good addition.

Just a thought to add:   If you don't mind (and have a place to put it) having an additional antenna, a simple 1/4 wave whip will do fine and avoid the splitter.   It doesn't take much of an antenna for reception of the AIS signal.  I made mine using an SO-239 chassis mount connector as the base with four brass rods attached to make the ground plane pointing downward at a 45 deg angle.  The antenna element was just another piece of brass rod soldered into a PL-239 connector.  Worked just fine!

John A.


Bob Miller
 

Glomex splitter from Hodges Marine
QK-A023 AIS wifi/USB receiver from Quark-Elec (UK)

If the splitter works okay, it's less gear visible. If not, plan B.


 

That's a darn good price on the splitter, but they're out of stock. :o(

https://preview.tinyurl.com/yx3qj6jk

or

https://www.hodgesmarine.com/glmra201-glomex-vhfaisradio-splitter--12vdc.html

Product info:

https://www.glomexstore.com/classic/232-ra201-glomex-splitter-vhf-ais-am-fm-for-boat.html

Bob Larkin has convinced me that a simple DIY dipole, even installed inside the cabin, will work fine for the AIS, and it's even cheaper than the Glomex splitter. "... the simple dipole for the AIS would probably be fine. The center conductor (about 17-inches) needs to be vertical, but the free braid can be bent if necessary to get enough room. You can add a wire or two to that, as well, but not needed if the whole dipole is vertical. Probably not too critical, even if the braid is sort of horizontal. Try to use 50-Ohm coax, like RG-58/U. TV coax is 75-Ohm and the braid is strange as it uses an aluminum wrapping under the braid."

I don't have room for something like this, but I found this simple DIY AIS antenna in my stash of boatbuilding stuff. (see attachment)

I'm gonna be using a "half wave whip" antenna for the VHF. Bob had something useful to say about that too (he's a fan of that type): "It benefits from, at least, some amount of formal ground plane at the point of the mounting bracket. The simplest is one or two 17-inch wires going down the mast, parallel to the coax. These can be hidden under a piece of wood, along with the coax."

On 3/8/2020 12:44 PM, Bob Miller wrote:
Glomex splitter from Hodges Marine
QK-A023 AIS wifi/USB receiver from Quark-Elec (UK)
If the splitter works okay, it's less gear visible. If not, plan B.
--
John <jkohnen@boat-links.com>
Self respect: the secure feeling that no one, as yet, is suspicious. (H. L. Mencken)
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I got the Quark QK-A027 through Amazon (but They don't sell it anymore):

https://www.quark-elec.com/product/qk-a027-wireless-ais-gps-receiver-with-seatalk-converter/

On 3/8/2020 12:44 PM, Bob Miller wrote:
Glomex splitter from Hodges Marine
QK-A023 AIS wifi/USB receiver from Quark-Elec (UK)
--
John <jkohnen@boat-links.com>
The latter part of a wise man's life is taken up in curing the follies, prejudices, and false opinions he had contracted in the former. (Jonathan Swift)
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This email has been checked for viruses by AVG.
https://www.avg.com


Bob Miller
 

I got the A023 (smaller and simpler) direct from the UK. $84.20  +  $13.35 Royal Mail.
https://www.quark-elec.com/product/qk-a023-ais-wireless-receiver/


Bob Miller
 

It looks like they'll be in stock by the end of the month or a little later

Or, try  https://www.boatandrvaccessories.com/products/glomex-ra201-antenna-splitter-vhf-ais-am-fm.
for $34.60 + free shipping.


johnacord
 

John,

That's the antenna I was describing!  Thanks for posting the picture.

I had that antenna mounted on the stern of our Gulf 32 and would receive the AIS signal at the max range of VHF even though it was mounted low and around a lot of rigging wires etc.

John A.


Bob Miller
 

This looks like a good DIY solution but I have no convenient or desirable place to mount it on my open 21'9" yawl. That's why I have chosen the multi-function whip antenna to place high and away with a splitter. Different solutions for different cases.


On Mon, Mar 9, 2020 at 10:05 AM johnacord <jcacord@...> wrote:
John,

That's the antenna I was describing!  Thanks for posting the picture.

I had that antenna mounted on the stern of our Gulf 32 and would receive the AIS signal at the max range of VHF even though it was mounted low and around a lot of rigging wires etc.

John A.


Bob Larkin
 

A couple more thoughts.  The John A antenna would be acceptable using 2 ground plane elements instead of 4, making it 2D instead of 3D.  That often can be tucked into the wall of a boat as high as practical.  For AIS, it does what is needed, almost always.  I have used essentially that antenna for AIS for years and years, resulting in stories, like the speck on the horizon that, on the AIS, is 90,000 tons coming at 19 kts on a collision course.  Good info to have!!

The splitter is a slight misnomer.  Because of the proximity of AIS and other marine VHF, it needs to also have a relay to disconnect the AIS when the VHF transmitter is on.  This needs circuitry and 12V power.  The real issue is that you are putting all that hardware un-reliability into the path of the marine VHF antenna.  That being one of our major safety items.  A less major issue is that the Glomex includes a 15-dB preamp to make up for the splitter loss.   The 15-dB is way too much and will create potential VHF radio overload problems that Icom and Standard worked hard to not have.  A separate antenna dodges both of these issues.

Bob


Bob Larkin
 

Also, try to attach the top, vertical element of the AIS antenna alongside a window, going up to a the cabin top.  A bit of trim wood over it, a coat of varnish and it will look dazzling.   Bob


Bob Miller
 

No cabin for me, open boat.


On Mon, Mar 9, 2020 at 2:09 PM Bob Larkin <bob@...> wrote:
Also, try to attach the top, vertical element of the AIS antenna alongside a window, going up to a the cabin top.  A bit of trim wood over it, a coat of varnish and it will look dazzling.   Bob


 

IIRC, my AO27 was about $125 from Amazon several months ago. It looks like buying direct from the maker in the UK is a good way to go.

Sorry, Bob L, after some serious thought, I sent off for a Glomex antenna splitter like Bob M's. It'll make the installation a lot easier, without the need to string wires all over the place.

https://preview.tinyurl.com/swhjxge

or

https://www.boatandrvaccessories.com/products/glomex-ra201-antenna-splitter-vhf-ais-am-fm

I'm reminded of the time I bought a new lawnmower instead of fixing the carburettor on my old, beatup one. Charley rebuked me, "you didn't fix the problem, you just threw money at it!" <g> I gave him the bold lawnmower. I don't know if he ever fixed it either. <g> At least the splitter isn't very expensive...

On 3/8/2020 5:35 PM, Bob Miller wrote:
I got the A023 (smaller and simpler) direct from the UK. $84.20  + $13.35 Royal Mail.
https://www.quark-elec.com/product/qk-a023-ais-wireless-receiver/
--
John <jkohnen@boat-links.com>
Life's more amusing than we thought. (Andrew Lang)
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Bob Larkin
 

Bob M - Or, put it on the bow, or somewhere, and tie a (Coot?) flag to it :-)    Sort of like
http://www.janbob.com/boat/BW2/bw2_detail.htm
(scroll down about half way.)


Bob Miller
 

Bob L - 

Thanks for the tips but I carry a bowsprit and boomkin and have no space on gunnels for anything that competes with lines for mizzen and gennaker, fender access, dingy boarding, or oar use. The masthead is it. It is what it is.


 

I strongly suspect that the antenna splitter defaults to letting the radio signal through if the power to the splitter is lost. But it does probably have a relay with contacts that could be damaged somehow, or just deteriorate with age. The overcompensation for the loss in the splitter is interesting. Why so much?

I'm rethinking my choice to use a splitter after I took a tape measure to Lazy Jack looking for good locations for a 1/4 wave dipole, and found one. <g>

The other day at Astoria I was talking to Bo and he mentioned having trouble figuring out which channel a call was coming in on when monitoring three channels on his radio. I mentioned that a Salish 100 support boat oughta have two VHF radios, one set to channel 16 and the other to the fleet channel, so you can just reply on the radio the call comes in on
. He said, "I did have two, but then I loaned you one!" Oops. This year I'm taking several VHF radios. <g> The "new" fixed mount radio and two handhelds, so I'll have two radios on all the time, and a backup I can loan to someone else if they have radio trouble, as I did last time.

Here's a list of useful VHF channels for the Salish Sea:

https://www.seattleyachtclub.org/vhf-marine-radio

On 3/9/2020 2:01 PM, Bob L wrote:
...
The splitter is a slight misnomer.  Because of the proximity of AIS and other marine VHF, it needs to also have a relay to disconnect the AIS when the VHF transmitter is on.  This needs circuitry and 12V power. The real issue is that you are putting all that hardware un-reliability into the path of the marine VHF antenna.  That being one of our major safety items.  A less major issue is that the Glomex includes a 15-dB preamp to make up for the splitter loss.   The 15-dB is way too much and will create potential VHF radio overload problems that Icom and Standard worked hard to not have.  A separate antenna dodges both of these issues.
--
John <jkohnen@boat-links.com>
America will never be destroyed from the outside. If we falter and lose our freedoms, it will be because we destroyed ourselves. (Abraham Lincoln)
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johnacord
 

Found a good discussion of AIS and VHF, especially explaining splitter loss.  Here is the link:
https://sas.cruisingclub.org/sites/default/files/asset/AIS%20Article%20-%20InDesign-July%2030%20FINAL.pdf
and have attached the pdf.

Page 5 in the pdf explains splitters and their losses.

I think one might come to the conclusion that a splitter compromises safety. 

Even though the splitter will (typically) have amplification on the received signals (not on transmit!) amplification will increase both received signal and add noise.  As far as transmission there will be losses, minimally attributed to the additional connections and possibly do to splitter design.  It is hard to determine all this as info about the splitter design may be hard to find.  Sometimes you can tell from the specs but rarely so.

John A.

 


Bob Miller
 

Current status = Handheld VHF(w/DSC) 6w, No AIS.
New status = Fixed VHF (w/splitter) somewhere over 6w up to 25w, realtime AIS
Difference = Net gain in safety.