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Old 19-06-2016, 12:23   #1
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HF DSC/Weatherfax Antenna Splitter

I have an Icom 802 and a Furuno Weatherfax. I would like to hook the DSC of the Icom up to the same antenna as the Weatherfax. As they are both "receive only" I figured it would as simple as buying a splitter but now having searched the web discovered that is not the case.
Im not looking to spend $100 on a duplexer but Im having a hard time finding a simple splitter rated other than 5 -1000 MHz. What happens to the frequencies lower than 5 MHz if I do use a splitter like this.
Thanks
Gary
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Old 19-06-2016, 16:41   #2
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Re: HF DSC/Weatherfax Antenna Splitter

Can I just use one of these?
Amazon UHF T

Sure there is no signal or impedance isolation but do I care?
Thanks
Gary
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Old 20-06-2016, 00:00   #3
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Re: HF DSC/Weatherfax Antenna Splitter

You do not need an antenna splitter for DSC. You do for a separate AIS system.
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Old 20-06-2016, 08:29   #4
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Re: HF DSC/Weatherfax Antenna Splitter

Gary,
You can easily use a simple coaxial "Tee" connector, and run the two HF receivers from one antenna!!!
This works quite well, and does NOT present any problems...

And, as luck would have it, this is exactly what I've been using on my own boat now for 12 years now...(and I have also done this on previous boats, using one receive antenna for a Wefax unit and a SW receiver, etc...even used it with a 200khz LW receive system for UK marine weather, and an HF WeFax unit, many years ago....and have done this on-shore with various HF receivers over the years, as well...)

{for my fellow purists out there, IF you were using poor designed radios that leaked LO signals and other images out-of the receiver antenna connector, yes you would want isolation between the two receivers that a simple coaxial "Tee" connector does not provide....BUT..
But, in the real world of modern HF radios (especially well designed/made radios, that were are talking about here), this isolation is unnecessary...and a simple coaxial "tee" connector will work well for an M-802's DSC receive antenna connection and a Furuno WeFax receive antenna connection...}

My current, and long-term, practical experience is in addition to my ~ 45 years of communications and electronics experience, including HF comms at sea and on shore, and > 30 years of running my own electronics and communications company...and I would not recommend this for other types of receivers (microwave, etc.) where receive isolation is important, but in the world of modern HF receivers this is completely acceptable...


And, the connector that I recommend is a Amphenol 083-1T
Adapter, UHF Tee Adapter, Jk-Pl-Jk | 083-1T | Amphenol RF

https://www.dxengineering.com/search...l-tee-adapters

The Amphenol connector is about $22...

Yes, you can find the cheap made-in-China copies for ~ $5, but they are usually crap....and I don't recommend them!


If you wish to see this actually working, LIVE, in real-life, please have a look at these videos....where you'll see both the Furuno WeFax and Icom M-802 in operation...(please note that these videos are hand-made, without any professional production, on my own 47' offshore cruising boat, by myself, alone....and there are some crude edits....but they are FREE and designed for the average layperson sailor in mind....so enjoy!)

Offshore Weather
https://www.youtube.com/playlist?lis...zdjTJjHlChruyY


HF-DSC Communications
https://www.youtube.com/playlist?lis...ga2zYuPozhUXZX


Icom M-802 Instruction Videos
https://www.youtube.com/playlist?lis...rC-8QKVyMb4tVr


Maritime HF Comms
https://www.youtube.com/playlist?lis...ZDo_Jk3NB_Bt1y


Offshore Sailing (two Atlantic crossings)
https://www.youtube.com/playlist?lis...KgTCj15iyl6qoY


(also note that there are individual videos that are duplicated in some of the playlists above....so, if you choose to watch all the playlists, you will see some of the videos twice...so you can skip past them....but...
But, they playlists are designed to give an overview of the entire subject, starting with the basics and finishing with the details, so most sailors will benefit from watching the videos in order on the playlists, rather than trying to watch an individual video here and there...)


BTW, here are some photos of my current set-up...







I hope this helps...

Fair winds...

John




P.S. To clarify for all, we are talking about HF receivers here, one is a six-channel scanning narrow-band HF-DSC receiver (built-into the Icom M-802)....and one is the Furuno HF WeFax unit (FAX-408 or FAX-50???)....
Quote:
Originally Posted by clownfishsydney View Post
You do not need an antenna splitter for DSC. You do for a separate AIS system.
This has nothing at all to do with VHF-DSC, nor AIS (VHF)....
Just wanted to clear this up, so the thread doesn't take a wild turn!!
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Old 20-06-2016, 10:46   #5
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Re: HF DSC/Weatherfax Antenna Splitter

Thanks for all the great info John.
That was the feedback I was looking for.
Im not near the boat right now and I can't remember exactly but I seem to think my Fax207 antenna port has a wire with a PL259 connector on it. Have you ever seen a product with three SO239 connectors thats worth buying. Amphenol doesn't make one.
Gary
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Old 20-06-2016, 12:30   #6
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Re: HF DSC/Weatherfax Antenna Splitter

Gary,
Yes, I have seen them....think Amphenol used to make 'em, but I think King's made 'em as well...
Quote:
Originally Posted by gpeacock View Post
Have you ever seen a product with three SO239 connectors thats worth buying. Amphenol doesn't make one.
Gary
But, to be honest, the way to do it is to use an Amphenol PL-258 "barrel" (double-female) connector and a "tee"...


Hope this helps..

John
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Old 20-06-2016, 23:13   #7
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Re: HF DSC/Weatherfax Antenna Splitter

Thanks
That's probably how I will end up setting things up.
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