Dual band marine antenna

[Captn_Black]

Originally Posted by Auspicious

You may find the SDR dongles ("RF - USB converter") disappointing. The radio performance (sensitivity and selectivity) is mediocre at best. I really wanted it to work but went back to a portable SSB radio. There is a detailed thread elsewhere here on Cruisers Forum.

If it works once a week on a 4 week atlantic crossing that is better than I have right now, which is nothing. And with the lack of charter tourists, even $50 is a stretch. But thanks for the info, I will try ere on the more powerful/larger size equipment available.

Edit - I have a hard time believing that a handheld SSB would be better at receiving than a 1/4 HF antenna, perhaps undersize coax was your issue? Or there could be other types of signal loss involved. I already have a USB power boosting adaptor, hopefully that, with a short, oversize coax, will do it.

[Auspicious]

Originally Posted by Brian.D

Well there is no 440MHz for Marine use, except EPIRB (406MHz).

UHF is commonly used for onboard communication on commercial ships - mostly between 460 and 475 MHz. There are even small repeaters that use the "leaky coax" method of distribution. Superyacht crews often do similarly using UHF GMRS which overlaps.

[Captn_Black]

Originally Posted by Auspicious

"Beware cut and paste sailors"

Haha, I like it! I once was looking for a fix to an engine issue, and had someone cut and paste my own post back to me that I had posted on another site, regarding a temporary solution I had come up with to the problem.

[Coquina]

Originally Posted by Dockhead

I have that very antenna on my boat too.


It's not tuned for marine VHF (and that's not what I use it for) but it works ok. It's very good on amateur VHF/UHF bands.

Good suggestion, thanks! I wonder if some ferrites would replace those little radials? AFAIK they are more to decouple the feed line than to be a ground plane, they aren't really big enough for that.

[AA3JY]

Try contacting Shakespeare maybe they can customize a marine VHF/UHF version.. I believe marine fire and police use UHF freqs on their response vessels ask them what they use. Also cruise ships use UHF but only for internal comms..

[Coquina]

Originally Posted by Captn_Black

If it works once a week on a 4 week atlantic crossing that is better than I have right now, which is nothing. And with the lack of charter tourists, even $50 is a stretch. But thanks for the info, I will try ere on the more powerful/larger size equipment available.

Edit - I have a hard time believing that a handheld SSB would be better at receiving than a 1/4 HF antenna, perhaps undersize coax was your issue? Or there could be other types of signal loss involved. I already have a USB power boosting adaptor, hopefully that, with a short, oversize coax, will do it.

I am going to second the notion re the SDR dongles. There are very good SDR radios available, but they are not the cheap ones. I have a cheap one and it does not approach being as a good as a "real" radio whatsoever.
Here are a few more things you might consider. First off, a receiving antenna is not critical as to length or layout. I have used a marine CB antenna and wire just strung out of the cabin temporarily hung on something to good effect to receive HF signals. Secondly, are you familiar with what HF WEFAX looks like and how to use it? Unless you have a decent signal and low noise, the chart might end up barely legible at best. Even if the charts come through 100%, there is a skill to knowing what you are looking at.

[Captn_Black]

Originally Posted by Coquina

I am going to second the notion re the SDR dongles. There are very good SDR radios available, but they are not the cheap ones. I have a cheap one and it does not approach being as a good as a "real" radio whatsoever.
Here are a few more things you might consider. First off, a receiving antenna is not critical as to length or layout. I have used a marine CB antenna and wire just strung out of the cabin temporarily hung on something to good effect to receive HF signals. Secondly, are you familiar with what HF WEFAX looks like and how to use it? Unless you have a decent signal and low noise, the chart might end up barely legible at best. Even if the charts come through 100%, there is a skill to knowing what you are looking at.

I am versed on interpreting 500mb weather charts, thanks. Although that is definitely a consideration for others considering this method. Plenty of books out there on the subject, though I will admit it takes some study and practice. Yea, the antenna is not the major factor, plenty of demo's on YT about building your own. I still don't see a better solution for my budget. I have a reasonable meteorological knowledge, so am not overly intimidated about making a crossing without weather info, but it would be nice.

[Auspicious]

Originally Posted by Captn_Black

Haha, I like it! I once was looking for a fix to an engine issue, and had someone cut and paste my own post back to me that I had posted on another site, regarding a temporary solution I had come up with to the problem.

Indeed. It's the out of context and irrelevant stuff that really irritates me.

Originally Posted by Coquina

Good suggestion, thanks! I wonder if some ferrites would replace those little radials? AFAIK they are more to decouple the feed line than to be a ground plane, they aren't really big enough for that.

I haven't found the little stubs to be in the way. You could write to Diamond and ask them. I find them responsive. Not fast, but responsive.

[Brian.D]

Originally Posted by Auspicious

UHF is commonly used for onboard communication on commercial ships - mostly between 460 and 475 MHz. There are even small repeaters that use the "leaky coax" method of distribution. Superyacht crews often do similarly using UHF GMRS which overlaps.

That would be GMRS. There are no Marine UHF Channels in the US. International, probably, but not here. I think the OP is wanting an antenna for the ham bands, not Marine bands. A lot of mobile antennas are just as good, if not better, than marine antennas.

JMHO

[Coquina]

Originally Posted by Brian.D

That would be GMRS. There are no Marine UHF Channels in the US. International, probably, but not here. I think the OP is wanting an antenna for the ham bands, not Marine bands. A lot of mobile antennas are just as good, if not better, than marine antennas.

JMHO

I do want it for ham bands, but there very much is a marine UHF band. It is used for intra-ship comms. If you see a couple deckhands on a tanker talking to each other or the bridge, odds are it is with UHF radios.
See this list at the bottom:
Also see this:
http://scanmaritime.com/frequencies.htm
Apparently some ships have onboard repeaters. It also seems like there is some overlap with GMRS and FRS in the USA.

[AA3JY]

Here ya go..

https://www.bjtek.com.tw/marine-vhf-uhf.htm

https://www.nauticexpo.com/prod/ante...08-511129.html

..but I don’t see the use of Stainless specs in their product discription..

[Auspicious]

Originally Posted by Brian.D

That would be GMRS. There are no Marine UHF Channels in the US. International, probably, but not here. I think the OP is wanting an antenna for the ham bands, not Marine bands. A lot of mobile antennas are just as good, if not better, than marine antennas.

CEPT has marine UHF frequencies. They overlap with but are more than GMRS. See links others posted above. The big international carriers often use GMRS channels because they fall under their CEPT licenses in the EU and GMRS in the US.

[smac999]

Comrad has a few dual band choices.

Here is one. 3.5 swr is pretty high though.

There is a graph but they don’t put numbers on

https://www.comrod.com/wp-content/up...VHF100512M.pdf

I currently have one of these in use for vhf ham only

https://www.morad.com/collections/an...antenna-146-hd

[Brian.D]

Fine. Is the OP a "big carrier"? No, so CEPT is irrelevant here in the US. I stay my course that there are no UHF Marine Channels in US territorial waters. Way off topic here as the OP wants to work Ham VHF/UHF.

Coquina, have you thought about building your own 2m/70cm vertical dipole?

[Coquina]

Originally Posted by Brian.D

Fine. Is the OP a "big carrier"? No, so CEPT is irrelevant here in the US. I stay my course that there are no UHF Marine Channels in US territorial waters. Way off topic here as the OP wants to work Ham VHF/UHF.

Coquina, have you thought about building your own 2m/70cm vertical dipole?

I have or maybe make just the 70cm part and use a splitter (duplexer?) and keep the VHF antenna I have. Come to think of it, the marine antenna I use now is a vertical dipole inside the tube and is cut for 156 MHz. 156x3 = 468 maybe it would actually work as-is with no new parts