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Author Topic: Icom 706 MK II G -- Out of band transmit  (Read 2197 times)
N3ZKP
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Posts: 2008




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« Reply #15 on: April 16, 2005, 03:13:44 PM »

<< Many manufacturers allow overshoot on the band edges to accomodate use on MARS nets. >>

If that were truly the case, there would be no need for the so-called MARS mod. All the Yeasus and Kenwoods that my MARS members use in Maryland had to be specifically modified to operate out of band.

Lon
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WA9SVD
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Posts: 2198




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« Reply #16 on: April 19, 2005, 12:23:46 AM »

I also suspect there's an economic and engineering factor involved.  Remember, the band allocations are not precisely the same for all three ITU regions.  That could mean having to produce three different versions of the same "model" radio, with different programming for slightly different band allocations.  (And with the upcoming 40M changes, a different nightmare!)  What's overlap in one region might be perfectly allowable in another region.  "Fine Tuning" the bands to precise frequencies might be cost prohibitive, and should a band allocation change or expand (or heaven forbid, shrink!)  too many hams would complain that their radio no longer operated through the whole band.
    As previously stated, it IS up to each operator to ensure that they ARE within the frequency limits of the band they are using, just as it's their responsibility to ensure they operate only on bands or portions of bands for which they have license privileges.  (Or should the manufacturers program their radios to warn or lock out operation when one goes out of the Novice portion of a band? or General, Advanced, and Extra portions?    Maybe you should have to contact the manufacturer and provide proof of License Class before the radio can be modified to transmit, with different "mods" for each class of license.)  The band edge "beeps" really are just a courtesy, and no guarantee.
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KL7IPV
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Posts: 984




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« Reply #17 on: April 19, 2005, 10:10:57 PM »

All my 706 radios were modified by me to use the 60 meter band. Before the "G" model, using the 60 meter bands at full power had a tendency to eat the PA. The "G" model is supposed to be better but run at a lower power to be sure.

   But when you do open the transmit it opens the radio completely for transmit almost anywhere it "hears. There is nothing wrong with that as long as you transmit where your license allows. GMRS and CB is NOT allowed since the radio is not type accepted for their use. In an emergecny situation, you can use the radio anywhere that gets you help. But if you do, you will have to file a report with the FCC to explain the emergency and what you did. Use it and enjoy.
Frank
KL7IPV
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K7UNZ
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Posts: 691




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« Reply #18 on: April 21, 2005, 10:35:19 AM »

RE:N3ZKP

As I am sure you are aware, MARS frequencies vary between the service branches, the type of net, the region, etc.  Not all fall within the "overshoot" range, and in that case you will need to modify your radio.  Some branches (i.e. Air Force) have/had nets which were easily accessable using just the overshoot range, others were not.

As the question pertains to an ICOM radio, I fail to see what that has to do with the modification on a Yaesu or Kenwood.  My Yaesu Gear (FT-990, FT-840), does need the general coverage transmit modification, as they have virtually no overshoot.  However, my Ten-Tec and Drake do not.  As I do not have any ICOM, I can't speak for that companies radios, thus the use of the term "many" manufacturers.
It was not ment to be all-inclusive.

73, Jim/k7unz



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N3ZKP
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Posts: 2008




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« Reply #19 on: April 21, 2005, 10:45:53 AM »

<< As I am sure you are aware, MARS frequencies vary between the service branches, the type of net, the region, etc. Not all fall within the "overshoot" range, and in that case you will need to modify your radio. Some branches (i.e. Air Force) have/had nets which were easily accessable using just the overshoot range, others were not. >>

As a former State MARS Director (and currently assistant SMD) I hear what you are saying.

What I am saying is that the "overshoot" really appies to older equipment and ICOMs. None of the modern Yeasu, Kenwood or Alinco HF rigs I have used had this overshoot. My TS-570 and both Alincos, for example, stopped dead on the band edges before modification.

Lon
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N3ZKP
Member

Posts: 2008




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« Reply #20 on: April 21, 2005, 10:49:41 AM »

<< Before the "G" model, using the 60 meter bands at full power had a tendency to eat the PA.>>

Not to mention that you were violating the rules for 60m operation. There is a 50w ERP limit on 60m, which means 50w into a zero gain antenna. If the antenna has gain, the output has to be reduced even further.

Lon
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WB6BYU
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Posts: 13243




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« Reply #21 on: April 21, 2005, 01:06:27 PM »

Actually, it would be legal to run 100 watts on 60m if
you have an inefficient antenna, such as a mobile whip.
As long as the efficiency was worse than 50%, you would
still be under 50W ERP.

But I'd much rather use a better antenna and cut the
power way back to the minimum required to get the job
done.
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WB2WIK
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Posts: 20595




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« Reply #22 on: April 22, 2005, 08:17:49 AM »

>by WB6BYU on April 21, 2005  Mail this to a friend!  
Actually, it would be legal to run 100 watts on 60m if
you have an inefficient antenna, such as a mobile whip.
As long as the efficiency was worse than 50%, you would
still be under 50W ERP.<

There's quite a lot of mobile activity on 60m around my area, and almost everybody's running a 500W PEP mobile amp...which is completely lawful, since the whip antenna systems have about -13 dBd gain.  It's the common mobile setup for 60m nowadays...

WB2WIK/6
 
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