On 4/20/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Sky Command does not do any control on 2 meters. This aspect of the rules has not changed. What did change is that an auxiliary link can now be used on 2 meters. This makes it possible to link into a 2 meter repeater in-band without violating the rules. I think that rule discussion is not permitted on this list, and apologize for this response. But a common misconception about Sky Command is that it does some control on 2 meters. In fact, it only uses the 2 meter band to transmit the receive audio from the remote installation. 73 - Jim W5ZIT
Agree -- the change was that Auxiliary Stations (see the definitions of station types) are now allowed below 222.15 MHz. They were not before. There never has been anything called a "remote base" in Part 97, ever. If you hear those words from someone claiming to know the rules, run away. They haven't read Part 97 if they're claiming those words are in there. "97.113(f) No amateur station, except an auxiliary, repeater or space station, may automatically retransmit the radio signals of other amateur stations." Period. Nice simple sentence in there that is clear. 'Nuff said, moving on. To get back on-topic... for the gentleman who was asking if he could link his systems by running a VHF user radio in/out of the VHF repeater... yes, you can do that now. You're probably going to need to do what one person mentioned -- at a bare minimum -- diddle with CTCSS on the VHF repeater so it follows user input. If you have switchable COS/CTCSS access for end-users, it adds some complexity -- you need both modes to trigger transmitted CTCSS from the VHF repeater when the input is active in whichever mode you select. Other things to think about: ID's: You'll also need to ID the link coming toward the VHF machine properly, (the link radio TX) so you'll need to figure out how you want the entire system ID'ed, and how you'll fix ID's if a portion of the system fails, if you're "passing them through" anything. You could play around with ID's being generated from the UHF machine and passed through the "system", etc... but if that link radio goes down and/or your timing of the link is such that it doesn't see a VHF "kerchunk", then the VHF transmissions could go un-ID'ed. I don't like that type of ID setup... I like to know each transmitter has its own, and that it's working all the time. If you can turn the CTCSS encode on/off on your link radio, you can keep the VHF system from "hearing" the ID... if your VHF machine is always in CTCSS access. But if you do that, surely people will double with the non-CTCSS ID transmissions on the VHF input once in a while. Duplex: You'll also have issues with full vs. half-duplex... which machine gets "priority" when users get going too quick on both sides at the same time? An even uglier one is if the system has an autopatch or any controllable features on the other end of the link... in that case, you'll have to think carefully about how the user can have priority over the other end, so they can maintain DTMF control of the user-feature when the "feature" is "transmitting". Also think about failure modes that include a locked/stuck transmitter or receiver at any point in the system and decide how you can get control and kill the offending component. That's usually an eye-opening analysis for some systems, too. In your situation, what you MIGHT want to consider is putting a dedicated link radio at the VHF site also, as mentioned by someone else... if a low (free?) antenna spot can be found that can make the 20 mile shot. It'd be a lot cleaner, overall, and you have more control over it then. Good canidates for linking frequences are low UHF, 220, and 900 MHz. Some people get a little wild and go up to 1.2 GHz, too. :-) You could even get fancy and set the link up full-duplex... if you have the room for the cans at the VHF site and radios that will do it. CTCSS decoding takes time, and many people find that non-sensitive receivers in commercial quality link radios with good front-end filters in carrier mode key up and switch faster than CTCSS-enabled links, making the link switching faster and more more "natural" during an end-to-end QSO. Lots of fun design decisions to think about when linking... Nate WY0X
