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"Bjarke M. Christensen" bjarkeNG@grevestrand_punktum_danmark wrote in
: Are you saying that the osc's in marine ht/ssb's are more stable that the osc's in ham hf/ssb's ? Why should that be so ? If icom can make it stable in the marine ssb; why don't they deploy the same technology in the ham ssb's ? I guess freq stability is a must for hams as well ?? Yes, of course. Ham radio has only one channelized band, 60 meters a new one, shared with government stations under a test for emergency comms in places like Katrina. All the other ham bands are broad strokes of frequencies you can operate anyplace in there you like. The radios have 10 or 100 Hz steps. Their master oscillators are cheaply made, not temperature compensated much as there is no need. Most have a trimmer on the outside of the radio so you can tweak it closer, yourself. Marine radios have temperature-compensated crystal master oscillators accurate to a standard. The M802 is: Operating temp. range : –30°C to +60°C; –22°F to +140°F Guaranteed range : –20°C to +55°C; –4°F to +131°F Frequency stability : ±10Hz (at –20°C to +55°C) This exceeds the .005% of the FCC standard for type acceptance. Hell, 10 Hz is closer than the 20 Hz of an AM broadcast transmitter costing thousands of times more. (Most AM transmitters, today, are within 1 Hz. You rarely hear much of a beat note at night on frequencies you can hear two or more stations transmitting on.) M802 also exceeds other standards for unwanted emissions that cause interference to other frequencies: Output power : 150, 60, 20W PEP (Selectable) Spurious emissions : –62dB Unwanted sideband : 55dB Carrier suppression : 40dB Its design also keeps you on the right sideband, USB, and its computer will not permit you to do technical things wrong users know nothing about that any ham radio will easily do if you just bump a knob or press the wrong button. All this is designed so that operators with very limited or no knowledge of radio transmitter operation can operate the marine HF radio without causing undue interference to other services and users by technical incompetence. It's why cop, business band, trunk radio and CB radios are so simple...a minimal number of knobs to screw up. UNfortunately, M802 has way too many buttons and knobs for most of its owners to use. It requires too much education the older SSB radios didn't need....Channel, Volume, Squelch, PTT microphone are all they should have. Japanese pride themselves in making anything they create into a technological wonder. M802 should make them all very proud. The other reason they don't make ham radios so stringent is simple....money. You can see it in the difference in price between an M802 type-accepted commercial radio and the Icom 706 ham rig. Few hams will pay for a type-accepted commercial-grade radio. Hams are an awful "cheap" lot. So, in response to the market...just like consumer electronics everywhere...Kenmore, Yahoo and Icum make 'em as cheaply as the market wants...just like that PoS TV in your living room. When the 802 is enabled for ham (using the procedure you describe) will it do both or do you have to toggle it back constantly ? It will do both. But, make SURE you put it back to channelized transmit before any Ship Inspections or you'll be busted. Pleasure boats are pretty much immune from ship inspections, but, if you look at your ship station licence from FCC, you'll notice they can come inspect your installation at any time for compliance. If I'm aboard, it's open so I can chat on 20 meters. If I'm not aboard, being the only licensed ham, I switch it back so my captain doesn't try to talk to BBC on 31 meters by mistake....one of his channels...(c; You often hear that marine ssb's are difficult to use on ham, as they are optimised for a fixed freq setting, and not for the more variable freq used on ham. How big a problem i that ? That is true of a lot of them. They are made to be channelized radios. When Icom made the M802, some ham infiltrated the design team and had them implement BOTH channelized operation, where the display shows you what marine channel you are operating on...and...a beautiful frequency display where the left knob chooses which digit to change with the right knob, giving you coarse and fine frequency control, AND, made it so the digit you're changing carries over when it switches anything from 9 to 0. The right knob acts just like a ham VFO, in 100 Hz steps which is close enough for hams. There's a little learning curve to switch the dials between modes but once you learn how and use it it becomes second nature very quickly. It's not a big problem at all on M802. The older and cheaper radios don't have this feature making them useless...which is what caused boaters to illegally use ham radios for marine radios in the first place....that and PRICE. Idont know you ham license structure, but where I live only the higest license level are allowed to use more than 100w. Can the 802 be configured to run only 100w on ham bands and 150w on marine bands ? Yes. The M802 has 3 power levels simply adjusted by the front panel buttons. From the webpage: http://www.icomamerica.com/products/...m802/specs.asp Output power : 150, 60, 20W PEP (Selectable) Another issue for your country is that I'm talking about USA type acceptance and the FCC, Federal Communications Commission. Although our government bureaucrats like to think they are omnipotent, they are not. Your laws and radio regulations ARE different than our, but probably accept FCC type acceptance as a matter of convenience. You may have more lax laws than the USA. Check with your radio bureaucrats for guidance on Marine installations. America has changed, recently. In the past, you had to have a 2nd Class FCC commercial radio operator's license to install and configure a marine radio. Owners were not allowed to do anything to it but use it. Now, owners are allowed to install it as long as the installation does not involve any adjustments to the factory-set, type accepted internal settings. The computer and transistor broadband amplifiers allowed this to happen as no radios require extensive tuning like they used to back in the tube days. They're all plug n play. I'm sure Danmark's radio bureaucrats have webpages about the laws, regulations and requirements for your country. Larry. |
#2
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posted to rec.boats.electronics
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![]() "Larry" wrote in message ... Marine radios have temperature-compensated crystal master oscillators accurate to a standard. Marine SSB's use an oven controlled crystal oscillator, not temperature-compensated ones. Ham rigs that have a high stability oscillator use the termperature-compenstated crystal oscillators. When the 802 is enabled for ham (using the procedure you describe) will it do both or do you have to toggle it back constantly ? It will do both. But, make SURE you put it back to channelized transmit before any Ship Inspections or you'll be busted. There is no need to do this. It is perfectly legal to put the 802 in open mode and use it on the ham bands. You do not void the warranty, the type certification, or break any FCC rules by doing this. You often hear that marine ssb's are difficult to use on ham, as they are optimised for a fixed freq setting, and not for the more variable freq used on ham. How big a problem i that ? It's not a big problem at all on M802. The older and cheaper radios don't have this feature making them useless...which is what caused boaters to illegally use ham radios for marine radios in the first place....that and PRICE. You can also easily open up the M710 and M700pro SSB's to operate on the ham bands and use the channel knob as a VFO control. As with the 802, you can only change frequency in 100hz steps or greater and it operates as a detented switch as opposed to the smooth rotary encoder of a ham rig. Eric |
#3
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posted to rec.boats.electronics
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In article ,
"Eric Fairbank" wrote: Marine SSB's use an oven controlled crystal oscillator, not temperature-compensated ones. Ham rigs that have a high stability oscillator use the termperature-compenstated crystal oscillators. May, or may not, be true, depending on the Radio Design. Type Acceptance does NOT define the design, it only specifies the Stability..... Bruce in alaska -- add a 2 before @ |
#4
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Well, I got a rig for my boat last winter and settled with the Yaesu 857D.
It seemed to consume less power in listening mode and also coverd 70 cm. Unfortunately, The Linux HamLib looks a bit aplha... Steve wrote: Is there anything to choose between these two sets for use on a boat on both ham and marine bands (after appropriate doctoring) ? I am inclining to the Yaesu, but largely because my main set in the FT-897 and I like it. I am a bit surprised by the advice to add an SSB filter and DSP to the Yaesu, that adds a lot to the price. How do the base sets compare? Thanks |
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