Caribbeachbum,
Contrary to the other posts here,
you CANNOT do this!!!
Please do NOT try this!!
Quote:
Originally Posted by Caribbeachbum
I picked up a Furuno WeatherFax unit on the cheap recently, and I want to hook it up such that it shares the backstay antenna with the SSB radio. I'm looking for an antenna splitter that does two things. I want the two devices to be able to receive simultaneously; and I want the SSB to go isolated when the transmit button is pressed, so as not to damage the WeatherFax receiver unit.
Does anyone know of a splitter product that will do this?
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1) There is NO "splitter", nor "diplexer", nor "duplexer" that will allow you to do this!!
{to be clear, there are transceiver-combiners, bandpass-filters, etc. that would allow sharing of one HF antenna to different transceivers (or transceiver and receiver), as long as their frequency / band of use was widely separated (a few MHz at least)....and some ham radio field-day operators and/or single-antenna contest stations have found them to be a workable solution to their antenna limitations on 14mhz, 21mhz, and 28mhz, etc....but these are quite pricey (> $500 - $1000), and are NOT practical for your application at all...}
2) Your best solution is to have your Furuno WeFax unit (I have the Furno FAX-408, myself) share your HF-DSC RECEIVE antenna....(which is what I've been doing now for > 11 years on-board my
current boat, and it works great!)
I use one of my aft lower shrouds as a coax-fed, end-fed vertical (about 22' long) and use a simple coax "tee" and a couple coax jumpers to feed both my M-802's
DSC Receive antenna jack and my Furuno FAX-408...
{Since MF/HF-DSC has been with us now since 1992, 23 years ago.....and has been mandatory for all SOLAS signatory nations and all SOLAS vessels since Jan 1999, > 16 years ago!! And, since then, MF/HF-DSC has been the ONLY way to raise/signal other boats, ships, vessels, or most coast stations (as they are no longer monitoring and Voice SSB channels/frequencies)!!
Except for some HF SSB Voice monitoring by the USCG, and Aus/NZ maritime authorities, (and Shipcom Radio's WLO/KLB) no one else is monitoring HF SSB Voice channels, and haven't been for many years....but there are > 450 MF-DSC coast stations worldwide and > 80 HF-DSC coast stations worldwide, that ARE monitoring the MF/HF-DSC frequencies....
So, with all of that, I'm assuming that you do have an MF/HF-DSC-SSB radio (such as the
Icom M-802, or Furuno FS-1575, sailor 6300 series, etc.)...which is why I mention "sharing" your "DSC Receive antenna" with your Furuno WeFax unit....}
Here are photos of mine...
3) If you do not have an MF/HF-DSC-SSB radio, or don't have an HF-DSC receive antenna rigged, you can simply use one of your shrouds, stays, etc. (as long as it is NOT electrically connected to your backstay antenna, and is at least a few feet away from your backstay), as a HF WeFax receive antenna....
4) If you truly wish to complicate your life....(something I do NOT recommend), you could buy an external "sub receiver / transceiver interface", which has an RF-sensed relay
network and an isolated receive output, all built-in....
It would cost you about $350 - $400....and would use only a little bit of 12vdc
power, but would be another piece of
gear to fail (they are NOT designed for the salt-air environment!) and another piece of
gear to complicate your life...
I do hope the above clarifies things...
Fair winds...
John