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Thread: 900 MHZ Band

  1. #26
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    Thanks for the link. Now I have to scrounge around for the IR SCM to play around with.

    Quote Originally Posted by Navy_BOFH View Post
    http://batboard.batlabs.com/viewtopic.php?f=43&t=93524

    This describes pretty well what could be done about trunking over ham. I would love to see it come to life even as a single-site prototype. The 800 to 900 conversion does look pretty straightforward however its requiring soldering and rework tools that I do not have at my disposal anymore. But if I could - I'd snatch up the repeaters and convert them all the time on my spare time.

    We looked at trying the trunking option here but the plan is to try the MMDVM/Quantar Link due to just sheer simplicity compared to getting a trunk system set up and a new key/codeplug from Motorola. The Quantar Link router/serial card/Raspberry Pi/cabling plus accessories would run probably around $150 and goes straight over IP while the IntelliRepeater side would require finding the right EPIC cards/firmware, plenty of setup and support from Mother M, and still needs to address the ability to link one site to another over IP which would require an ATM switch or Intraplex to get the V.24 serial over to IP while maintaining all the trunking system functionality.


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  3. #27
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    Full edit after original post:

    I answered my own question with a tab I already had open!
    http://wiki.w9cr.net/index.php/Quantar

    Bryan has already listed the firmware with a zip file to flash it to the SIMM chips with an EEPROM burner or jig.

    I think my spare SCM might need that treatment for playing around... if I can ever find a dang VHF R2 PA to complete my repeater!

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    Forgot to add... Intellirepeater versions used a SIMM with 8 sockets instead of 4. Now I wonder if it can be simply soldered on and modified or if I need to find a source of the SIMM...

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    There's an IntelliRepeater SCM on eBay for $125 right now.
    Cyrus

    Bubbles: I'd like to see that Red Blue Green c***sucker put one of those together, duct-tapin' it.

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    Quote Originally Posted by axel View Post
    One of my stupid long-term goals is to implement a somewhat functional trunking system on the 900 ham bands...
    It would have to be 9600 P25, unless you want to go with LTR or DMR. Any flavor of 3600 trunking uses hard-coded channel tables for 900 MHz that cannot be edited, short of hacking the firmware in every single radio you wanted to use.

    Having said that... with a PSC9600 controller and a handful of Quantars with EPIC IV control cards running the right firmware, it *could* theoretically be done. 9600 P25 handily transmits the system call sign in the control channel data stream, so there's your workaround to keep the kilocycle cops happy. The biggest issue would be trying to piece a system together out of Ebay parts and getting everything to play nice together... it is Astro25, so everything has to be at the same system software version. Then you'd have to build a TX combiner and RX multicoupler network to get everything into two antennas (and avoid intermod issues.)

    You could, however, run an IR/3600 system on 2 meters or 70 cm, since those are considered OBT and have flexible channel tables.
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  8. #31
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    Quote Originally Posted by motorola_otaku View Post
    It would have to be 9600 P25, unless you want to go with LTR or DMR. Any flavor of 3600 trunking uses hard-coded channel tables for 900 MHz that cannot be edited, short of hacking the firmware in every single radio you wanted to use.

    Having said that... with a PSC9600 controller and a handful of Quantars with EPIC IV control cards running the right firmware, it *could* theoretically be done. 9600 P25 handily transmits the system call sign in the control channel data stream, so there's your workaround to keep the kilocycle cops happy. The biggest issue would be trying to piece a system together out of Ebay parts and getting everything to play nice together... it is Astro25, so everything has to be at the same system software version. Then you'd have to build a TX combiner and RX multicoupler network to get everything into two antennas (and avoid intermod issues.)

    You could, however, run an IR/3600 system on 2 meters or 70 cm, since those are considered OBT and have flexible channel tables.
    Hence why I said stupid long term goal

    A trunked ham system would be nice, especially in 70cm flavor since we wouldn't have to buy new HTs for everyone in the club. But getting hold of a second 70cm quantar is not a cheap endeavor, even this long after they've been EOL'd. It's just something I've always tossed around in my head that would be solely for the cool factor and not much more.

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    The name is escaping me... but there was a company out there (still around but relatively unknown) that made their version or LTR trunking where the repeaters had a trunking controller for each repeater, but they only held a I am X designation. The radio did all the negotiation on PTT to find a clear repeater, send the Talk Request, repeater would acknowledge and sent a data burst out to tell other radios to switch over, and etc.

    Essentially the radios scanned for all programmed repeaters in the trunk system and did the thinking for the controller. Initial PTT was a bit delayed but once you got a conversation going it was quick. After the end of the conversation the repeater would drop back into the inactive pool and the radios would start scanning again.

    Last I saw of it the company sold some modules for Motorola radios but has in recent years been making their own radios with their own digital format.

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    Took me a minute to drag the name of it out of my brain. SmarTrunk II was the technology.

    It seems to be the hams answer to trunking if it wasnt for the fact its not popular at all.

    So OBT trunking seems to be the only other logical idea based on popularity.

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    SmarTrunk II has a major flaw with late channel entry... in that there is none. You have to wait for the other user to de-key before your radio can join the conversation.

    Hardware-wise a PSC9600 system would probably be the most economically feasible to implement since the controllers themselves are available for reasonable and 800 MHz stations to pull controller/wireline cards from are a dime a dozen.
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  13. #35
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    Quote Originally Posted by motorola_otaku View Post
    SmarTrunk II has a major flaw with late channel entry... in that there is none. You have to wait for the other user to de-key before your radio can join the conversation.

    Hardware-wise a PSC9600 system would probably be the most economically feasible to implement since the controllers themselves are available for reasonable and 800 MHz stations to pull controller/wireline cards from are a dime a dozen.
    The 800 repeater part is definitely true. I ordered one just for the SCM/wireline/power supply/chassis which ended up being cheaper than trying to source the pieces by far. I am going to look for a couple PSC9600s next to play with.

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    Quote Originally Posted by Navy_BOFH View Post
    The 800 repeater part is definitely true. I ordered one just for the SCM/wireline/power supply/chassis which ended up being cheaper than trying to source the pieces by far. I am going to look for a couple PSC9600s next to play with.
    There is a PSC9600 on ebay right now for 250.00. I looked at the guys other auctions, and he seems to be asking more money than most of the things are worth, so not sure if 250 is a deal or not. https://www.ebay.com/itm/MOTOROLA-PS...-/191781289213

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    Quote Originally Posted by wiredwrx View Post
    There is a PSC9600 on ebay right now for 250.00. I looked at the guys other auctions, and he seems to be asking more money than most of the things are worth, so not sure if 250 is a deal or not. https://www.ebay.com/itm/MOTOROLA-PS...-/191781289213
    I'd hold off... they usually go for less than $100.
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