ICOM IC-78 HF SSB RADIO

[kev_rm]

This stuff is way over my head but do any of these "issues" actually affect the safety or performance a real world marine application (even if it is illegal) ?

The reason I ask is I suspect the genesis for the emissions rules has a lot to do with playing nice in a dense urban environment.

Originally Posted by Hartleyg

The actual term is "emission mask", and the limits are expressed as suppression of signals that are outside the emissions mask. For Part 80 & 90 (and government under the NTIA) the limits are emissions outside the nominal emissions bandwidth (which can be either 2.8 kHz or 3 kHz), depending on the service involved within 1.5 kHz (26 dB) or 1.75 kHz of that edge (28 dB), and from the that edge to 3 kHz away (35 or 38 dB). Beyond the outer edge either 40+10log(Px) or 43+10log(px) is the limit. This ultimate requirement corresponds to an absolute limit of either 100 or 50 microwatts.


So when a radio expresses it's "spurious suppression" as 46 dB (like the IC-78), it clearly can't meet the 40/43 +10log(Px) requirement. As far as the close-in requirements, this is measured under specific "two tone" conditions using a spectrum analyzer.
Amateur radios don't have to meet anything but the "ultimate" requirement, and that limit is only 50 dB of suppression, so generally a radio manufactured to amateur specs won't meet those of Part 80 (Marine) or Part 90. The reason for this, of course, is that most amateur HF bands are harmonically related, so harmonic energy falls into another amateur band (and is therefore of little concern to regulators



In addition, there is an important caveat with solid-state transmitters, which is pretty much all of them nowadays. These transmitters generally use low-impedance broadband amplifiers followed by low-pass filters, and this becomes a serious problem with an amateur radio, as these filters are designed to support amateur-band operations, and may not offer sufficient performance if used outside of those bands. The spurious radiation well away from the channel in use is usually harmonic radiation, and if the transmitter filtering isn't up to it, significant interference can result.



Low-voltage operation can indeed lead to distortion and create out-of-limit sidebands close to the operating frequency, so the voltage range of an approved transmitter is important!


All these things are contained in both the FCC and ITU regulations, and I suspect most countries follow the ITU recommendations pretty closely. For US Maritime stations, 47CFR80.211 (a) is pertinent.


Hartley
S/V Atsa

[S/V Illusion]

Originally Posted by Hartleyg

The actual term is "emission mask", and the limits are expressed as suppression of signals that are outside the emissions mask. For Part 80 & 90 (and government under the NTIA) the limits are emissions outside the nominal emissions bandwidth (which can be either 2.8 kHz or 3 kHz), depending on the service involved within 1.5 kHz (26 dB) or 1.75 kHz of that edge (28 dB), and from the that edge to 3 kHz away (35 or 38 dB). Beyond the outer edge either 40+10log(Px) or 43+10log(px) is the limit. This ultimate requirement corresponds to an absolute limit of either 100 or 50 microwatts.


So when a radio expresses it's "spurious suppression" as 46 dB (like the IC-78), it clearly can't meet the 40/43 +10log(Px) requirement. As far as the close-in requirements, this is measured under specific "two tone" conditions using a spectrum analyzer.
Amateur radios don't have to meet anything but the "ultimate" requirement, and that limit is only 50 dB of suppression, so generally a radio manufactured to amateur specs won't meet those of Part 80 (Marine) or Part 90. The reason for this, of course, is that most amateur HF bands are harmonically related, so harmonic energy falls into another amateur band (and is therefore of little concern to regulators



In addition, there is an important caveat with solid-state transmitters, which is pretty much all of them nowadays. These transmitters generally use low-impedance broadband amplifiers followed by low-pass filters, and this becomes a serious problem with an amateur radio, as these filters are designed to support amateur-band operations, and may not offer sufficient performance if used outside of those bands. The spurious radiation well away from the channel in use is usually harmonic radiation, and if the transmitter filtering isn't up to it, significant interference can result.



Low-voltage operation can indeed lead to distortion and create out-of-limit sidebands close to the operating frequency, so the voltage range of an approved transmitter is important!


All these things are contained in both the FCC and ITU regulations, and I suspect most countries follow the ITU recommendations pretty closely. For US Maritime stations, 47CFR80.211 (a) is pertinent.


Hartley
S/V Atsa

You are quoting the criteria for testing by the manufacturer which I understand.
The problem here is someone quoted test results without knowing who did the testing, how it was done or under what condition the testing was done.

interpreting the results is therefore dubious and it’s important for people to understand the spectrum emissions of ham radio equipment can and often is much better than so-called marine (read - more expensive) radios.

[Hartleyg]

Originally Posted by kev_rm

This stuff is way over my head but do any of these "issues" actually affect the safety or performance a real world marine application (even if it is illegal) ?

The reason I ask is I suspect the genesis for the emissions rules has a lot to do with playing nice in a dense urban environment.

Well, we're talking about HF radio here, so the WHOLE WORLD is involved, depending on the vagaries of propagation . Microwatts of spurious power radiated from a transmitter can affect receivers hundreds or thousands of miles away.
Yes, nearby receivers will be affected more, but think about it - we aren't always out on the high seas when we use our SSBs, and getting clobbered by someone who is sharing your anchorage (or the next one over) isn't any fun either.



Hartley
S/V Atsa

[Hartleyg]

Originally Posted by S/V Illusion

You are quoting the criteria for testing by the manufacturer which I understand.
The problem here is someone quoted test results without knowing who did the testing, how it was done or under what condition the testing was done.

interpreting the results is therefore dubious and it’s important for people to understand the spectrum emissions of ham radio equipment can and often is much better than so-called marine (read - more expensive) radios.

Absolutely true, and some of techno-ignorance being passed around the Internet on subjects like this is very discouraging. That said, in order to be offered for sale, those Marine radios have had to meet MUCH more stringent requirements than ANY amateur radio. Things like harmonic suppression, transmitter IM generation and synthesizer spurious are all serious issues, and getting them under control costs money - which is why Marine radios cost more than amateur radios. (Even if the receivers in some amateur equipment often out-perform the ones in Marine radios!)


If you think there is any data that supports your allegation that amateur radios out-perform Marine radios ON MARINE FREQUENCIES other than anecdotal, I'd like to see it.


Hartley
S/V Atsa

[shepaug]

Ever hear RF NOISE ? Ever see these little stickers on things where they are not supposed to interfere with other devices like radios ? Ignored now. A light bulb can knock out your radio reception.(NOISE)

When radio was new regulations were created to try to make such sane as far as things like interference.

I mention USA regulations. There are international agreements and regulations. -- BUT possession of a radio is not a crime.. You can have an old BBC 5 million watt transmitter in your garage and nothing wrong with that. BUT are those the laws in Somalia ? Who knows !!!!!

I do not know the deal with HF MARINE. I think they want boats and ships, etc. to have complicated communications on board but to my thoughts are they just catering to certain manufacturers ? Almost any amateur radio transceiver can be modified to go on marine channels with a simple thing they call MARS modification. I'd bet there is little wrong with such emissions. BUT it is a NO/NO. Got to be certified !!!! Then by who ? Malaysia ?

In USA it is illegal to listen in on cell phone conversations. Blocked in the radio. Then people just buy the radios from elsewhere. (most this stuff is encrypted so a waste of time to pursue anyway)

New Software Defined Radios (SDR) cover all frequencies and have heard of no efforts to change that.

This new Chinese stuff. Allot of VHF/UHF radios but they are getting into HF slowly. These radios transmit anywhere. BUT don't get excited as my observation is there are so many BUGS in these radios who wants them ? (defects) HF amplifiers now. I read one review and it sounded like such might ruin your transmitter. Emissions ? Usually terrible. Widely sold on places like EBAY.

Regulations ? If you wanted to communicate on a marine channel and impossible due to garbage from garbage transmitters ?

I am selling nothing. Just enjoy radios.

That ICOM 78 is sort of a mystery. I'll leave one link but I think any company outside of USA can sell non-USA-certified radios. I emailed this company once and got no answer. I suspect ICOM just does not want to market them.

https://www.universal-radio.com/catalog/hamhf/1664.html

(no affiliation !!!!)
-------------------------------------------------------------------------------------

[stimpsonjcat]

It's pretty simple/cheap to test the harmonic suppressions with the proliferation of cheap SDRs these days.

You're still not legal...but you can tell if the emissions are within the regs or not.

[flyingnut40]

Well said Hartley,
This actually saved me looking up the difference in certification specs between Ham and Marine radio transmitters.

The band filtering on Ham radios based on harmonic band spacings made sense and given the MUCH wider marine spectrum explains why the Ham radio is unlikely to be in spec over the wider spectrum allotted to Marine ops.

I sold my beautiful ICOM 756 Pro, which I loved and bought the ICOM802 and now I know why... that and the fact that the 802 is channelized with ALL THOSE CHANNELS to make our marine ops easier/ safer is a no brainer.

Add in the DSC features that will be heard thousands of miles away yet redirect a ship 50 miles from you cannot be ignored as an amazing safety feature that a ham radio would fail to do.

Add in easier Pactor integration, with frequency control etc. and I am completely comfortable trading in my 756 (that cost $3700 back in the day) for a $1800 radio CERTIFIED to do what we need it to do.

Making Ham contacts is easy peasy once you put it into VFO mode.
Glad I made the switch.
Dennis de VE3XDA

[Cadence]

Originally Posted by denverd0n

I think it is also important to remember that just because the radio CAN transmit on marine frequencies, that does not make it legal to do so. If you are a U.S. citizen, licensed by the FCC, and you use a radio that is not FCC certified to transmit on marine frequencies, in any situation other than an emergency, then you are violating the law.


Odds of getting caught, of course, are nearly zero. And I don't judge anyone who uses one of these radios on the marine frequencies. Nonetheless, it's worthwhile to realize just what you are doing, and to understand that you are violating the law (except, as I said, in case of an emergency).

I liked that, the chances of getting caught are about nil unless you are a constant transmitter from a given location and then it is probably nil plus one.
A cheap radio may " spatter all over adjacent frequencies " causing someone with a real need to be SOL

[s/v Jedi]

I would like to see a citation for a micro watt or two of spurious emissions causing interference thousands of miles away. Until then, I call BS on that.

[flyingnut40]

Wouldn't that be at the carrier stage? What does it become after punching it into a 100 or 200 watt final amplifier?

[s/v Jedi]

Originally Posted by flyingnut40

Wouldn't that be at the carrier stage? What does it become after punching it into a 100 or 200 watt final amplifier?

Spurious emissions are measured at the antenna connector.

[flyingnut40]

O.K.

[Hartleyg]

Originally Posted by stimpsonjcat

It's pretty simple/cheap to test the harmonic suppressions with the proliferation of cheap SDRs these days.

You're still not legal...but you can tell if the emissions are within the regs or not.

Being somewhat familiar with the critical nature of this testing, please explain how a "cheap SDR" can measure spurious emissions from an HF radio?


Hartley
S/V Atsa

[Hartleyg]

Originally Posted by s/v Jedi

I would like to see a citation for a micro watt or two of spurious emissions causing interference thousands of miles away. Until then, I call BS on that.

Its pretty unlikely that such an interference source could be identified and documented.
That said, if you ever get on HF-SSB, note the ever-changing noise, weak signals and other oddiments that interfere with listening in on even a very quiet channel. How could you prove that ISN'T some trash transmitter running half a world away? The point of the emission rules is to minimize potential interference, not to block "documented" interference.


I actually said "microwatts" - the radio model that initiated this thread (the IC-78) is rated at -46 dB of transmitted spurious, so it could be emitting these signals at +4 dBm, or about 2500 microwatts. It might even be higher if the operating frequency is on a band that it isn't spec'd for (which is a mystery, since the spec sheet won't tell us what those bands are). Similarly, those amateur radios with their spec of -50 dB of transmitted spurious also tend to make note that their specs are "only within the amateur bands" (likely as a result of the nature of the low-pass filters used).

Maybe I should have used the term "milliwatts"? Certainly transmitted spurious at that level will interfere with receivers within the anchorage.



Hartley
S/V Atsa

[stimpsonjcat]

Originally Posted by Hartleyg

Being somewhat familiar with the critical nature of this testing, please explain how a "cheap SDR" can measure spurious emissions from an HF radio?


Hartley
S/V Atsa

You set the DUT radio to min power, CW or FM mode, tune the SDR to see that freq, TX the DUT and note the magnitude.

Then Set the SDR to the 1st harmonic and do it again.

Check delta vs spec.

Now the splatter nature of the output is a little harder to evaluate, but when I did this test on the Baofeng HTs I had it was pretty hideous stuff.