VHF, OK, BE HONEST, DO YOU KNOW...

Although the sample here is small and voluntary, I am getting the impression that north American sailors are more likely to know about simplex/duplex than Australian sailors even though the knowledge is nearly irrelevent within North America. I say nearly because I always figure it's better to know something than not. You just never know... you might wind up somewhere... someday where...?

I have learned more here than I bargained for. eg... What may be regarded here as "useless knowledge."is your bible and visa versa. Particularly on my part of the coast, "assigned frequencies" are so few and far between it creates the impression that the whole dial is your playground, which creates the very comical scene of a frustatred boaty screaming into his mike trying to call a boat on the other side of the island and not having a clue why it aint happenen. You see, most of the commonly used freq's here are duplex. All the channels monitored by coast guard/VMR are duplex and sailors tend to just leave that last used freq on. I take for granted how wonderfuly isolated most of this coast still is.

I would only suggest at this point that American sailors heading to faroffistan, refresh their understanding of the difference so you can laugh along with me at the locals when you get here!

Thank you all and please note that the freq charts that have been supplied by Kai Nui and Talbot have already been posted on my web site.

Cheers

Good deal It is interesting how lax the manufacturers have gotten about including quick reference guides with the radios. Since most of us do not have the attention span to do the research and learn about it until it is more of a priority, like right before we take off for parts unknown, Just adding a quick reference guide to the radio packet would work wonders.
I suspect one of the reasons that US sailors might have a better familiarity with simplex vs duplex is in the early 90's there was a boom on ham radio licenses, and the advent of the tech and tech plus class brought people on the air that would have otherwise had no interest in this technology. Of course, with the advent of the Nextel walkie talkie, and cell phones becoming more affordable than landlines, the interest has faded to a large degree.
Remember when you needed a license to use a CB?

[hellosailor]

"Remember when you needed a license to use a CB?"

Ahem, and a ship's station license to use a marine VHF?<G>

Ahhh the good old days

[coot]

Originally Posted by Bob Norson

All the channels monitored by coast guard/VMR are duplex and sailors tend to just leave that last used freq on.

Don't you use channel 16 as the standard calling channel?

Hey Coot!

yes, 16 is the common hailing freq but many avoid it so they don't have to shift once in touch. That and every novice goes through the trauma of getting chewed out for "working the channel".. but mostly it's ignorence and just plain lazy. After a session of screaming into the mike many will go to 16 and try that and wonder why the other didn't work... but still when I ask in the anchorages, only about one in 6 know. Amazing!

[GordMay]

BoatUS presents Chuck Husick
http://www.boatus.com/husick/

See the index of articles at the left, including:
“VHF Radios” http://www.boatus.com/husick/c_vhf.asp
“VHF Radio Antennas” http://www.boatus.com/husick/c_antenna.asp
as well as many more.

Chuck Husick, contributing editor to this year's Guide to Marine Electronics and other major boating publications such as Sail, Cruising World and Power & Motoryacht, just to name a few, has over 43 years of technical experience in the field of electronics, with a specialization in avionics and marine electronics.

Thanks Gord, very useful little articles.

I copied your links and have them posted on that web page along with a few other notes to help people decipher the info.

to see revisions www.thecoastalpassage.com/vhf.html

Cheers Mate

[Tom E]

Calling all Radio Smart Guys - is there such a product as a dual use aviation/marine handheld? (...and yes, I just HAD to pick the two most expensive pursuits that exist) - Tom

[GordMay]

Tom:
I wouldn’t expect* so.
Bearing in mind, that it is illegal to use handheld or fixed VHF (Marine or Aviation) radios on land, unless you have a Coast or Ground Station license (or a Marine Utility Station license), I wouldn’t suspect that anyone would be manufacturing handhelds covering both frequency bands (156-17 MHz Marine and 108 - 136 MHz Civil Aviation).
It would be difficult to operate a radio from both your boat & aircraft, simultaneously.

*I don’t really “know” for certain, but I just know that someone’s going to prove me wrong, on this one ...

[Canibul]

I no longer use a brand new, never been outside the house, Icom handheld aircraft VHF I bought for my ultralight flying. I contacted Icom to see if they could convert it to marine for me....nope.

[Tom E]

I guess float plane guys would qualify. Or would they need two separate radios?

Anyway, thanks GordMay. Honestly, I would only use the marine capability on the water and the aviation capability in the air. Oh well, at least GPS works for both.

Canibul, if you want to give your VHF hand held a new home....I'd pay shipping to Hawaii

-Tom

[hellosailor]

Gord, what do seaplanes use? Or more precisely "flying boats" ?

Two sets of radios required??

I'd expect someone makes a type-accepted dual purpose radio for that market--but since it is first and foremost "marine aviation" I suspect it would carry a steep price tag.

I had a formal "SHIP/AIR STATION LICENSE" issued to me by the FCC, and it was formally endorsed as "PORTABLE", not assigned to a single vessel. I have no idea if this is still possible, I know the regs have changed since then. I just called them up and said "I want my own license for my own radio, I crew and move among different vessels" and that's what they issued. All one and the same.

(Doesn't affect the legality of using it on water /vs/ land, obviously.)

Canibul-
ICOM-America and other distributors (or even the parent makers) will not convert ANYTHING because every radio sold commercially must be "type certified" "accepted" or in other ways regulated for a specific market, and the FCC allows near zero tolerance about that. If a commercial radio was type accepted or certified for any market, the manufacturer can't risk making any changes, for any reason.

On the other hand, just about anyone can "remanufacture" anything and submit it for new or varying certifications and approvals. Whatever that's gonna cost.<G>

[Radio University]

Also keep in mind that the Aviation frequencies are AM modulated not FM like the Marine Frequencies. It is a totally different circuit board. They do not use one circuit board for all their product line. Each board is specifically designed for each radio...

[hellosailor]

James-
There are a number of radios (not necessarily HT's) that do both AM and FM. I've got an HT that is rx-only on AM, but rx+tx on FM. Covers air and marine bands, but will only tx in fm.

I've made no attempt to confirm this, but have been told some of the fm schemes (reactance/vs/phase/vs "true" fm, I forget which) will produce intelligible signal on AM under certain conditions. Any idea about that?