Icom ID-5100 D-STAR issue?

Discussion in 'Working Different Modes' started by AF7ES, May 7, 2014.

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  1. AF7ES

    AF7ES Ham Member QRZ Page

    I've been happily using VE7SUN B for D-STAR with several other radios. Great signal from them, they hear me just fine as well.

    No joy with my new Icom ID-5100 radio that arrived yesterday.. It works fine with the other repeaters in the area, however, with VE7SUN-B, transmissions I receive back from the repeater are not being decoded by the 5100, it seems to think it is some odd mix of FM and D-STAR. This is using the same antenna/coax that work fine with several other radios here, and the signal strength received is super strong.

    People on VE7SUN can hear me talking just fine though.

    Someone nearby told me he suspects VE7SUN isn't using an Icom Repeater/gateway, and all the other ones are.

    Anyone know anything about Icom getting troublesome with non-Icom hardware?

    The ID-5100 works fine talking to my DVAP, which is in the same band as VE7SUN is.
     
  2. AF7ES

    AF7ES Ham Member QRZ Page

    And some more data on the configuration of VE7SUN:

    Freestar, Motorola Mitrek radio, Sinclair 310C-4 antenna.
     
  3. AF7ES

    AF7ES Ham Member QRZ Page

    I just performed another test to make sure I wasn't losing my mind - I plugged back in my ID-880H, and it works flawlessly with VE7SUN, even if I set it on low power here. Decodes transmissions from VE7SUN perfectly, and VE7SUN is replying to my echos with no loss.

    Something strange is afoot inside the ID-5100.
     
  4. VK3ERW

    VK3ERW Ham Member QRZ Page

    A fellow HAM is experiencing a similar problem where the ID5100 fails to decode DV coming from a DVAP yet decodes transmissions from other Icom radios without any problems. Even when the ID5100 is set to simplex DV mode is still refuses to decode the signal. A 7100 running beside the 5100 decodes the same transmission without any problems.

    Something strange indeed - did Icom modify the firmware to refuse decoding of non-com generated DV streams?? I hope not.
     
  5. KD4MOJ

    KD4MOJ XML Subscriber QRZ Page

    I was going to order one but I decided to let other folks find the bugs first... :cool:

    ...DOUG
    KD4MOJ
     
  6. VK3ASC

    VK3ASC Ham Member QRZ Page

    I am the Ham VK3ERW has mentioned above. The DVAP was set to 438.912.50mhz. I changed the frequency on the radio to 438.910.00 and all worked fine. May be the repeater is slightly off frequency with the DV Signal. Try tuning the ID5100 off frequency slightly and see if that works. Cheers...
     
  7. VK3ERW

    VK3ERW Ham Member QRZ Page

    Problem solved!

    It appears the ID5100 has better selectivity than any of it's for runners and the DVAP was about 2-3kHz off frequency which was enough to cause ID5100 to stop decoding yet the 7100 and 51A decoded fine, it seems they are not quite as selective on DV.

    Anyone with similar issues should start by changing the frequency on the ID5100 up/down in very small increments until it starts decoding and then let the operator of the repeater/DVAP/??? know that their transmitter is not on frequency.

    The DVAP has an internal calibration parameter (preset at the factory) which is easily overwritten when it's used with a Rasperry Pi or similar device.

    I retuned the DVAP and the ID5100 decoded it's transmissions without any further problems :).
     
  8. KD4MOJ

    KD4MOJ XML Subscriber QRZ Page

    Glad you two found the issue!

    ...DOUG
    KD4MOJ
     
  9. VK3ERW

    VK3ERW Ham Member QRZ Page

    To be fair to ICOM I should say they have improved selectivity on the ID5100 and that improvement seems to show up the shortcomings (i.e. TX off frequency) of other equipment (repeater, DVAP, etc).
    Credit to ICOM, this is certainly not a problem with the ID5100 and certainly not a bug.

    Technical details of our findings:
    The tests conduct by VK3ASC and myself indicate that the IC7100 will decode successfully when set to around +-3kHz of the transmitting frequency.
    For example, to decode a transmission on 438.9125MHz the IC7100 can be tuned to any frequency between 438.909 and 438.915. I was surprised to find such a wide frequency window.

    Unfortunately they ID5100 tuning steps don't allow 1kHz increments so we can't do direct comparison, but it is sure to be somewhat less than +-3kHz.
    I suspect the ID 5100 would be +-1.5 or 2kHz.

    The DVAP was set to 438.9125MHz but the offset correction was 0 (probably my fault when commissioned on RaPi). Our tests indicated that the DVAP was actually transmitting around 438.909/10. The ID5100 refused to decode when set to 438.9125 but was OK on 438.910.
    Entering a DVAP offset [DVP_OFFSET] value of -200 (range is -2000 to +2000) brought the DVAP transmission frequency up to 438.9125 and the ID5100 decoded without any further problems.

    Measuring method used:
    Unfortunately I don't have spectrum analyser, so my measurements are [very close] approximates derived by working out the centre of receive edge frequency using VK3ASC's IC7100. The resolution is only 1 kHz, so my measuring error would have to be stated as +-1kHz, and is based on the IC7100's frequency being accurate (which I believe it is).

    Erwin
    VK3ERW
     
  10. KE5MC

    KE5MC Premium Subscriber QRZ Page

    Erwin,
    Is it possible that the 7100 had FIL1 (15K) selected and the 5100 had a narrower selection?
    Mike
     
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