I have a 50 foot sailboat and have purchased an R75 wanting to listen to various USB cruiser "nets" but am unsure how to deal with the antenna. My previous boat had an Icom M802 transceiver which was connected via coax and an automatic antenna tuner to an insulated section of the stainless backstay. Noise was generally not an issue with the M802 while receiving but testing the R75 with just a random wire outside the cabin along the deck (30 feet?) all I hear is noise...maybe at times I can barely hear WWV but that's it. Note that my testing was done in a marina with lots of other boats nearby and connected up to shore power...however with all the electronics now installed and operating even when offshore I suspect my noise problems are at least in part locally generated and won't go away. Can someone suggest a possible solution? I have spare halyards that can be used to haul up temporary long wire type antenna but not sure that'll help the noise problem. Any thoughts/suggestions will be greatly appreciated.
R75 R75 boat antenna question
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mmckenna
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There's a lot of noise sources around you, and laying an antenna on the deck like that is sure to suck them all into the radio. USB chargers are a huge source of noise, but all the other electronics are working against you.
I'd try hoisting a vertical antenna up the mast and see how it works. Using an insulated backstay is another good option. Since a lot of sail boats use that for SSB, the hardware is out there and it would be easy to set up.
If this is receive only, and you don't have an antenna tuner, take a look at an end fed antenna. It has an impedance transformer in the base that will help improve performance.
I'd try hoisting a vertical antenna up the mast and see how it works. Using an insulated backstay is another good option. Since a lot of sail boats use that for SSB, the hardware is out there and it would be easy to set up.
If this is receive only, and you don't have an antenna tuner, take a look at an end fed antenna. It has an impedance transformer in the base that will help improve performance.
Yes thanks...this is receive only and I was tending toward an end fed antenna with a transformer which would then allow me to connect to the radio using the coax connection. But I have no ground so not sure the coax will really help with local noise pickup. Any thoughts on the ground issue?
mmckenna
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Does the boat have a ground system, zincs, etc?
mmckenna
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West Marine, so it's expensive, but you could try this, or make your own:
mmckenna
I ♥ Ø
Yeah. There should be some zincs mounted through the hull. Those are usually used as a ground connection. Find one of those (probably in the engine compartment) and give it a try. You'll likely find one with the negative battery terminal connected to it, the engine block, etc.
If not, toss a piece of wire over the side weighted down. Won't last forever, but it'll give you something to try.
Actually I know the boat doesn't have separate zincs mounted through the hull...only those on and protecting the prop shaft. I'm not near the boat just now to confirm but I'm 99% sure. In any case, when I do return to the boat, I will try using a connection through the prop shaft (engine block) as a ground. Thanks again for your help!
mmckenna
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Using the prop shaft may or may not work well since it's just a mechanical connection and not an electrical connection. Probably fine if the engine isn't running.
You can also look for bronze fittings going through the hull below water line, like the sea chest/strainer.
You can also look for bronze fittings going through the hull below water line, like the sea chest/strainer.
mmckenna
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If it's a sailboat, see if you can access the keel.
mmckenna
I ♥ Ø
OK, well, I think the through-hull fittings would be a good thing to try. Especially if they are bonded to the engine block and the rest of the boat.
I used to do some short wave listening while at sea, and it was always good. Getting away from all the noise made listening a pleasure.
I used to do some short wave listening while at sea, and it was always good. Getting away from all the noise made listening a pleasure.
ka3jjz
Wiki Admin Emeritus
A loop might work well here, altho the coax and fittings would have to be treated for a marine environment. It would no doubt help with at least some of the noise. Mike
w2xq
Mentor
Very strange story.. I wonder if the noise in the receiver is coming through the receiver's power connection to the sailboat's electrical system. Disconnecting the antenna should tell the story.
Decades ago I helped a friend install an ICOM HF transceiver--I don't remember the model--on his 32' sailboat docked at his place in Beach Haven. I no longer remember the how-to of power and ground and antenna connections, but we used the backstay as the antenna. It worked very well. The first contact was a 4X4 on 20m. In mid-afternoon 40/41m was active; the European broadcasters and R Moscow were all over 41m.
I would think the backstay would be the best antenna for the R75. I never found my R75 to be fussy about what outside antennas were connected. The near vertical backstay should be sensitive to low takeoff angle signals, more so than any wire or loop on or near the deck.
I look forward to learning what you find.
Decades ago I helped a friend install an ICOM HF transceiver--I don't remember the model--on his 32' sailboat docked at his place in Beach Haven. I no longer remember the how-to of power and ground and antenna connections, but we used the backstay as the antenna. It worked very well. The first contact was a 4X4 on 20m. In mid-afternoon 40/41m was active; the European broadcasters and R Moscow were all over 41m.
I would think the backstay would be the best antenna for the R75. I never found my R75 to be fussy about what outside antennas were connected. The near vertical backstay should be sensitive to low takeoff angle signals, more so than any wire or loop on or near the deck.
I look forward to learning what you find.
Possible a 12VDC to 120VAC inverter making noise?
prcguy
Member
Not counting the noise problem, I would run coax to the backstay and attach a 9:1 balun there and that should provide good reception. The noise will have to be found and fixed to make reception more pleasant.
Thanks for the feedback...after several months away from the boat (I'm in California & the boat is in Puerto Rico) I'll be heading back mid-October. Based on the generous feedback I've had here and elsewhere, I have several things to try. Regards a back stay antenna...I've had transceivers (M802) that hooked to the back stay on other boats however they required an insulated back stay which I don't currently have & for sure the back stay is connected to the boat's ground system. However I can use the rigging to support a long wire antenna (probably not a permanent install) with a balum...at least it's one option to try. I'll probably just start by disconnecting all power to/from the batteries and shore power, then connect the R75 direct to the batteries...if that's not quiet or at least quieter I don't know what I'll do!!
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