Sailing Boat Antenna Help

Hi

I'm hoping that someone can help.

I have been interested in amateur radio since my school's days in the amateur radio club and have also always loved sailing. I now find myself trying to combine the two interests and making a receive only setup for my boat focusing on the MF and HF bands.

I however am really struggling to select an antenna or set of antennas with a selector switch that will provide the best possible reception for use on a 26ft sailing boat.


I would be really grateful to hear any advice you have regards to antennas and related equipment to point me in the right direction. Further details are below.

Many thanks

James


Boat:
Contests 26 sailing boat with a single 28ft aluminium mast and wire rigging. Hull made of Fiberglass and an inboard diesel engine.


Boat radio:
Software defined radio SDR play RSP1a connected to a raspberry pi 4 using the software cubicSDR and Fldigi


Frequencys required using one or two separate antennas:


Navtex on : 490khz 517khz


Weather fax on : 3855 kHz, 7880 kHz, 13882.5 kHz and 2618.5 kHz, 4610 kHz, 8040 kHz, 11086.5 kHz 18261kHz


Marine communication and safety information: 2172kHz, 4125kHz, 6215kHz, 8176kHz, 8291kHz, 12290kHz, 12359kHz 16420kHz, 16537kHz


Other installed equipment:
Icon marine VHF set with marine VHF antenna mounted at the top of the mast.


Budget: trying to keep the cost down as much as possible but don't mind spending money if it really makes a difference.


Thanks again.

 

Any chance you can insulate the forestay or backstay from the mast using heavy-duty ceramic compression insulators?

 

Perhaps I could find some way of insulating the backstay. Would another wire attached to the backstay work that is insulated?
If I went for this option would I need an antenna tuner?
If so could I set one up that was set with permanent capacitors so I could switch a switch for each frequency instead of having to tune it. Or is there an automatic antenna tuner that works on frequencies down to 490kHz.
My worry with antenna tuners is that it might be tricky to tune on a noisy boat if I am sailing and have to quickly pop down to pick up a navtex message in a hurry.

 

I have not seen any amateur market tuners that go below 1800 kHz !
I wonder what was used in the big ships when they were required to listen on the 500 kHz emergency freq. Must have some kind of adjustable loading incuctance on a short (for that freq) antenna .

 

If you are receiving only, you do not necessarily need a resonant antenna or even a means to tune one. An appropriate broadband amplifier can work well with an antenna of undefined length or even a loop to provide a decent signal for a receiver. At the frequencies you are looking at, I'd probably shoot for a loop.

Mike
AF7ON

 

Assuming the stays are metallic, you can load these (in parallel, or separately) with a good antenna tuner, and use the mast as a reflector. Switching stays will give you some steering ability on the higher HF bands. For Navtex, it's hard to beat a good small shielded direction finding loop. It can serve as a backup navigational aid as well.

 

An end fed wire running the length of the ship was pretty standard.

 

Thanks so much guys for your help I have been looking into this for ages and found it really hard. You have helped more in 5min than in my 5days of research. Would you then both perhaps recommend a backstay antenna with or without a tuner for the higher MF frequencys and the HF frequencies. and then a separate Loop antenna for navtex on 490 and 518kHz

 

That would be my choice...no reason to try do do it without a tuner, though....tuners cover a multitude of sins. (Nichols Law)

 

Thanks so much guys for your help I have been looking into this for ages and found it really hard. You have helped more in 5min than in my 5days of research. Would you then all perhaps recommend a backstay antenna with a tuner for the higher MF frequencys and the HF frequencies. and then a separate Loop antenna for navtex on 490 and 518kHz if so what would be the best way to switch between the two.
Also sorry for my lack of knowledge but could you clarify how you set up the stays (in parallel, or separately) so as to use the mast as a reflector. Thanks again