Freeband and MARS/CAP mods?

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johnny-bravo

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Hello, im new to this forum and know someone here will be able to explain to me what the term freeband and MARS/CAP mods are, I have a Yaesu vx-7r and have downloaded the commander program and when I download the freeband I only have 2 or 3 bands to switch between and when I download the MARS/CAP I have many more to choose from, I know its illegal to transmit and i will never but im curious as to what I am actually doing to the radio? also is it possible to use the freeband with the MARS/CAP? cause as of now it seems like im just downloadin one or the other or I just havent figured out how to do both at the same time? I havent been able to really find a guide to the commander program

thanks and please be gentle with me lol
 

mmckenna

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Welcome, Johnny.

Freeband is a term used to describe transmitting on unused frequencies, frequencies someone isn't licensed for, etc. It's often used in relation to modified CB radios running on frequencies between the CB band and the 10 meter amateur band. Sometimes it's referring to using a radio outside it's designed operating area.

MARS/CAP mod is the modification that MARS/CAP members used to be allowed to do to amateur radio gear to use it outside the amateur radio bands. MARS = Military Affiliate Radio Service. CAP = Civil Air Patrol.
Not sure about MARS, but I'm pretty sure CAP no longer allows this.
It's commonly used by amateur radio operators/freebanders and others to allow an amateur radio to operate outside the amateur radio bands.

Yeah, it's illegal on paper because most amateur radio gear does not have the FCC type certifications necessary to transmit anywhere outside the amateur radio bands. People do it anyway.


Basically all these do is remove the internal restrictions on the amateur radio gear that prevents it from accidentally being used to transmit outside the amateur radio bands. In the old days it was a jumper that was moved/removed or a wire cut. More modern radios its just a software setting.

The issue with it is that most radios have at least some filtering on them to prevent the little bit of interference that all radios generate from interfering with other users. This filtering can reduce performance on the amateur radios when used out of band.
Also, power output might be reduced.
 

johnny-bravo

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thanks mmckenna for taking the time to explain these features, I have read that doing this could also damage the equipment because of the power and antenna but I was really only interested listening to these other bands, so do you know if its possible with the commander program to unlock both? like I said I cannot find a guide to commander and im afraid if I play around i may end up ruining the yaesu, if anybody has a link to a commander programming guide please share it, im usually really good at finding this information myself and not one to be spoon fed but im at a loss
thanks again
 

johnny-bravo

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this seems to be one of the only documents i found thats close to a guide but it doesnt fit the version of commander that I have

http://www.hayseed.net/~jpk5lad/K5LAD files/Yaesu_VX-7R/VX-7 downloads/VX7 Commander v.10/MODS.txt

As with the use of VX7 Commander, mods will be done at your own risk!
Note, it is generally ILLEGAL to transmit on bands you are not licensed on
except in an emergency.

You should read and understand the following before activating software mods.

On the mod screen, all fields shown are the current settings from the VX7
file loaded into VX7 Commander, except for the "Current Config" byte.



THE SETTINGS:

If you try a lot of different mods, you should leave "Enable Mods" checked.
When this is unchecked, VX7 Commander ignores the mods and the default
current config byte.

There are 4 buttons at the top of the screen, for the different mods.
Click one of these, the settings will change to the proper ones automatically.

The "Current Config" byte is the current configuration of the VX7.
The "Virtual Jumper" byte is the one to change for mods.

Byte 8 and Byte 9 should not need to be changed, unless you need to
use a file from a Japanese VX7 on a US model, or vice-versa. These must be
set to the same as the VX7 being written to, or you will receive a "CLONE
ERROR".

Bytes 12, 13, and 14 can be changed freely, without receiving a clone error.

I don't know what byte 12 is. I do know it is 00 in the Japanese VX7, and
01 in the US.

Byte 13 - When set to 00 = Ham Only RX
When set to 01 = Wide RX
When set to 02 = Wide RX (Everything I have seen is set to 02)

Byte 14 - When set to 00 = Ham Only TX
When set to 01 = Wide TX

Both bytes 13 and 14 are 00 after doing a MON/F + HM/RV + Internet Key
reset toggle (Euro?).


DETAILS:

After writing to the VX7, the "Current Config" byte stored in the VX7 will
be the same value as the "Virtual Jumper". So then if you read from the VX7,
you will see that the "Current Config" and "Virtual Jumper" are identical.

If you try to write to the VX7 and have the "Current Config" byte set
differently than the one stored in the VX7 , you will get a "CLONE ERROR".
However, it should not erase any of the VX7's memory.

I tried to make this easy to manage: as long as you have "Enable Mods"
checked, VX7 Commander will always default to the "Current Config" based
on your last read or write to the VX7, and will use that when writing.
This should make it easy to write different mods to the VX7 without any
problems.
So in you should never have to change the "Current Config", unless you
hardware mod your VX7, use Commander to mod on another PC, managing more
than one VX7, etc.
If you do get a "CLONE ERROR", simply read from the VX7. This will
automatically set your "Current Config" byte to the proper value.
This byte can also be changed manually.

Here's the Known Settings for the Virtual Jumper:
Unmodified E0 = (11100000)
MARS/CAP F0 = (11110000)
Freeband E8 = (11101000)
Japanese? F8 = (11111000)

***NOTE: After changing anything in the Mod screen and clicking OK, changes
are applied to the file data loaded into VX7 Commander. Anytime you save
after this, the modification changes you made will be written to your vx7 file.
This means that when loading the file again, you will not have to change
settings on the mod screen in order to perform the mod again, since the mod
is written into your file. But take care not to save to a file you do not want
saved in this way.
Also, if you have "Enable Mods" checked, the "Curent Config" byte will always
be changed in any vx7 file you open. So when you save then file, the "Current
Config" byte will be written to your vx7 file.


I do not know any more about the mods than I have written here.
I have tried some different settings for the Virtual Jumper and the others. The
VX7 accepts them, but I haven't noticed any major changes in the VX7's behavior.
Feel free to try different settings, let me know what you find out.
I would like to know what these are set at on different VX7 versions. It would
also be nice to be able to correlate these with actual hardware jumper settings.

Jim
KC8UNJ
 

SCPD

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What would be cool if you posted the frequencies you get after you mod it.
You could always use FRS and MURS frequencies without getting the FCC involved.
 

mmckenna

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What would be cool if you posted the frequencies you get after you mod it.
You could always use FRS and MURS frequencies without getting the FCC involved.
There's that pesky lack of Part 95 type acceptance thing that might get in the way.

Sure, while it's possible (if the VX7 will transmit 2.5KHz deviation on FRS and the 3 narrow MURS channels) it's still not legal.
 

bharvey2

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If you don't intend to transmit, I'm not sure the Freeband/MARS/CAP modifications will provide any advantage, Mind you, I'm not a Yaesu expert although my HF radio is a Yaesu. It his a great deal of receive coverage (much greater than its transmit coverage). A quick look at the VX7 specs show that it has almost continuous receive coverage between .5-1000mhz.

While it would be handy to have one "Do All" radio, I leave my radios as they came from the factory. It's harder to be accused of "being naughty" with your radios if they don't have the capability to transmit out of band. - Much less of a temptation to do so too.
 

wyShack

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Also remember that the 'mods' generally only allow the CPU to key the transmitter out of band. They do not change the output filter. Most (I would guess all) amateur radios have a low pass filter after the transmit finial amplifier. This filter is designed for the ham band and may (or may not) provide a good match for 'out of band" frequencies. The filter at other frequencies could do some strange things as far as 'loading' the finial amp in terms of reflected power ect. A SWR meter after the filter is not in the 'right' place to see this mismatch. You need to either analyze or measure the filter response at the operating frequency. that is why most MARS/CAP operation is 'right next to' the ham bands-to take advantage of the fact that manufacturers will leave 'a little room' for manufacturing tolerance. If you go way out of band you can be at a point where the filter/matching network is way out of what the amps expects to see and at a point where protective circuits are not 'looking'. This can cause the smoke to get out or other bad things (like spurs harmonics and the like). Most of us do not have the equipment to check (or the full parameters and knowledge to analyze). The operator is still responsible and the warranty is out the window. You can transmit into a dummy load and use a spectrum analyzer to verify purity and still burn up the finial-not a good deal.
 
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