Visit our Popular Forums

fairbank56 · 02-10-2012, 10:27

Quote:

Originally Posted by S/V Illusion

I often wonder whether these folks who warn us how illegal it is to operate a ham radio on marine frequencies have ever driven their car over the posted speed limit potentially endangering others. The horror!

You might think twice about speeding if the fines were commensurate with FCC fines. The current base forfeiture amount for operating radio transmitting equipment on an unauthorized frequency is $4,000. The FCC regularly hands out notices of violation to people violating the rules. The vast majority of these are the result of someone else issuing interference complaints to the FCC.

The amateur radio service is for qualified people who are interested in radio technique for self-training, intercommunication, and technical investigations solely with a personal aim and without pecuniary interest. The maritime mobile service on the other hand is primarily to provide for safety of life and property at sea and on inland waterways. Two entirely different radio services intended for two entirely different things. There are reasons that the equipment for different radio services are restricted to transmit only on the authorized frequencies for that service.

Eric

S/V Illusion · 02-10-2012, 10:43

Quote:

Originally Posted by skipmac

Being a scofflaw from way back the regulatory technicalities don't concern me but there are some potential technical details that could come into play.

The specifications for radios certified for marine SSB use are tighter than the specifications for radios certified for use on ham bands. I believe the channels on marine bands may be closer together requiring tighter bandwidth to avoid interference on adjacent channels.

PS
I never drove 55 mph.

Now a good ham radio may meet the requirements for marine band transmissions, whether it's certified for it or not, but some certainly don't and I think it would be considered discourteous to bleed all over your fellow boaters transmissions.

I don't know if you are also a ham but I've had probably hundreds if not thousands of qsos (contact with another ham) during which someone was transmitting 3 KHZ (or less) away with no interference to either party. Many of those contacts with so-called "boat anchors" meaning vintage equipment no where near current standards. Correct me if I am wrong but the marine channels are separated by much more.

I am not disputing the legalities. Only wanted to observe how some people are seemingly so hypocritically law-abiding in one context but not others where the potential harm is vastly greater. That seems ironic to me.

ka4wja · 02-10-2012, 12:27

Billion,
By this time, you've already seen the boat, and no doubt have found the amswers you were looking for....
So why am I bothering to answer you???

Simply for clarification and education....

1) Eric is correct the radio is an Icom IC-725, ham radio transceiver.

2) And, Bill is correct that the manual tuner is an older MFJ.

3) However, what was not mentioned:
a) The IC-725 was without a doubt the worst HF ham rig Icom ever made.
It was an entry-level radio with a poor rec front-end and if stages....with poor IMD specs, etc...susceptable to overload, etc....no rf gain, etc...ineffective features, etc....poor longterm main ocsillator calibration, etc..etc.
And, its transmit specs are also crap!!!
I've only heard a 725 on-the-air a few times in recent years (thank goodness), but when you hear one you'll know it...

The vast difference between the 725 and the remarkable IC-735, is unbelieveable!!!
(Anyone who's used a 735, knows that it is a great little radio...and even 20 years on, can still compete well with other "modern" rigs!!!)

b) Depending on the antenna used (assuming some type of insulated backstay, or wire, or whip) with the set-up pictured, the amount of RF (and RFI) floating around the Nav Station is going to be quite high, and problematic!!!
Severe distortion, and/or radio transmt issues are the usual result of having a random-length end-fed wire antenna so close to the radio, microphone, etc...

c) the fact that the listing mentioned "single sideband radio", and they were referring to the IC-725, tells me that someone was seriously stretching the bounds of "ethical advertizing".....

d) If you combine these 3 items (a,b, and c)....you come up with:
--- a not-so-good radio
--- a piss-poor installation
--- deceptive advertizing
And, these add up to a warning to either steer clear of this boat, or be aware that much of what you wil be told by the seller/broker will be, at best, an exaggeration. And, at worst, staight-out lies...

I do hope this helps...

John
s/v Annie Laurie

Celestialsailor · 02-10-2012, 13:14

I agree with what everyone here has said thus far. I will add that i intend to "clip" my diode to only listen to different channels on SSB nets. I find a lot of the information there is nice to have. I have a Yaesu 840. It's my 3rd one. Simple and works well. In regards to the Seafarers net. My hats off to them. They provide a great service even if the net control gets a little chatty some times.

**skipmac** · 02-10-2012, 13:29

Quote:

Originally Posted by S/V Illusion

I don't know if you are also a ham but I've had probably hundreds if not thousands of qsos (contact with another ham) during which someone was transmitting 3 KHZ (or less) away with no interference to either party. Many of those contacts with so-called "boat anchors" meaning vintage equipment no where near current standards. Correct me if I am wrong but the marine channels are separated by much more.

I am not disputing the legalities. Only wanted to observe how some people are seemingly so hypocritically law-abiding in one context but not others where the potential harm is vastly greater. That seems ironic to me.

Not a ham but was an EE in a former life. Focused on digital circuit design but at one time did have a passing aquaintence with things like frequency, wavelength, bandwidth and such.

So was not certain of the specific reasons as to why, just recalled that marine HF radios have tighter specs to meet and some ham radios due to
transmitter output that is not as well regulated will cause interference in adjacent marine channels. Another ham on the forum who you probably recognize posted a pretty good summary of the technical differences between marine and ham HF radios. Hopefully he won't mind my copying it below.

Regarding the legal hypocrisies, you will get no argument from me on that subject. I think calling it ironic is often an understatement.

In addition to "type acceptance", there are real differences between ham radios and marine radios. The differences are not just in type acceptance, spectral purity (reduced "splatter"), and cost. Anyone who tells you different is either trying to make the case for spending less money, or they simply don't know what they're talking about.

Some of these differences include:

1. ability to operate effectively at lower input voltages (as often is the case on a sailboat with partially depleted batteries), without either severe FM-ing (distortion) or simply cutting out (as some ham radios do);

2. ease of operation....fewer controls, channelized operation, etc. This makes it far easier for a non- radio person to operate the radio in an emergency; and

3. marine radios tend to have superb audio quality, both on receive and on transmit. Typically, they easily surpass many/most ham rigs in this department.

Coupled with their spectral purity and frequency stability, this package of "features" makes most marine radios come in a cut above most ham radios for SSB operation on the marine bands.

However, they are typically less well suited for ham operation, because they :

1. have less frequency agility (yes, even the Icom M-802 isn't as easy to use on the ham bands);

2. lack many of the controls and features hams like to have (RF gain, CW keyers built-in, dual VFOs, notch filters, etc., etc.).

I sell and install both marine and ham radios on boats and have some 25 HF radios in stock at the moment...ham radios, marine radios, military radios, land mobile radios, aircraft radios. Many of these are connected and are operational during the workday...listening on ham, marine, aircraft HF frequencies. By the way, HF/ SSB radio is not just the principal means of communication between ground controllers and long-distance aircraft in Africa as was mentioned above, but WORLDWIDE. Still.

I have two favorite radios which I operate daily on various ham and marine nets: a Kenwood TKM-707 marine SSB and a Yaesu FT-920 ham radio. The TKM-707 is a very, very simple radio....or so it would appear from the very few controls. But, it is a very sophisticated radio, with excellent performance. Alongside it is the FT-920 -- a very complicated radio. There are almost 80 knobs and buttons on the front panel, compared to 14 on the TKM-707, plus a keypad behind a little door.

They're both great radios. Both are technically capable of operating on the ham bands and the marine bands. Only one can be legally operated on the marine bands (the marine type-accepted TKM-707), provided you have the necessary marine station and operator licenses.

Both can be legally operated on the ham bands, provided you have a ham license.

As the previous post indicated, there's often not much difference in cost between ham and marine radios, particularly used ones. I have used ham and marine radios beginning at under $500. In any event, the difference in cost between marine and ham radios is a very small portion of the total cost of installation, counting the antenna tuner, the antenna system, the ground system, and the materials and labor for a proper installation aboard ship.

One strategy, which I use on my boat, is to install BOTH a ham rig and a marine rig. That way, you can have the best of all possible worlds, and be perfectly legal. And, if you choose quality used radios, you can do it for the cost of a single new marine SSB.

Here's a pic of my boat, with a Yaesu FT-900CAT ham radio on the left and a Yaesu System 600 marine radio on the right (the one with very few knobs). And, further to the right is a PTC-IIe SCS Pactor modem which will work with either radio. NavStn_0140

Bill