Loading ...
Sorry, an error occurred while loading the content.

Re: [RTrak] RTrak Tuning?

Expand Messages
  • lists@ke4nyv.com
    ... Are you set up for dual frequency operation?  That could cause what you are describing.  There is also the chance that your mobile might not have very
    Message 1 of 3 , Oct 26, 2012
    • 0 Attachment
      > (1) My 2m voice rig occasionally picks up the beacons from the RTrak when I'm 
      > tuned to 145.390 (local repeater) even though the RTrak is broadcasting on 
      > 144.390, and...

      Are you set up for dual frequency operation?  That could cause what you are describing.  There is also the chance that your mobile might not have very good adjacent channel rejection and you're hearing a harmonic.

      > (2) Compared to my earlier setup (an OT w/ a Yaesu VX-170) my packets aren't 
      > being consistently picked up by the local APRS network. I'd say maybe 1 out of 4 
      > transmissions is successful.

      That does sound like the deviation is not correct.  When you say "picked up by local APRS network" how are you verifying that?  Direct decode local with an actual radio?  Looking online to see if it shows up?  If it's the latter, keep in mind the transmitter is only 350mW, so unless you are in the air or fairly close to a digipeater, I don't expect the RTrak-HAB to show up online.  It's all about being heard by an iGate, to get the packet to the internet.

      > Based on the above, I'm wondering if I have a transmitter deviation problem. 
      > What's the best way to "tune" the RTrak?

      The BEST way is with a calibrated RF service monitor that has a deviation meter.  In general the packet audio should be 3.5-4 kHz.  I tend to find that it needs to be on the higher 4 kHz end.  We "marry" each tracker to an MX145H transmitter and then do final alignment.  That way, you're getting an aligned tracker with the actual transmitter that it ships with.

      If you don't have access to an RF service monitor, one method is to listen to other packets on the network and then try to adjust the RTrak-HAB to transmit at roughly the same audible level.  This can be hard for some people to do, but it's not too difficult to get close.  1200 baud packet is somewhat forgiving in this regard, but it can't be too out of whack or else nothing will decode it.

      Jason Rausch - KE4NYV
      RPC Electronics, LLC
      www.rpc-electronics.com


      --- On Thu, 10/25/12, sdrumm_98 <swdrumm@...> wrote:

      From: sdrumm_98 <swdrumm@...>
      Subject: [RTrak] RTrak Tuning?
      To: RTrak@yahoogroups.com
      Date: Thursday, October 25, 2012, 11:02 PM

       

      I've noticed two problems with my latest RTrak installation:

      (1) My 2m voice rig occasionally picks up the beacons from the RTrak when I'm tuned to 145.390 (local repeater) even though the RTrak is broadcasting on 144.390, and...

      (2) Compared to my earlier setup (an OT w/ a Yaesu VX-170) my packets aren't being consistently picked up by the local APRS network. I'd say maybe 1 out of 4 transmissions is successful.

      Based on the above, I'm wondering if I have a transmitter deviation problem. What's the best way to "tune" the RTrak?

      Thanks!

      73
      N3XFD

    • sdrumm_98
      ... you are describing. There is also the chance that your mobile might not have very good adjacent channel rejection and you re hearing a harmonic. Yep.
      Message 2 of 3 , Oct 27, 2012
      • 0 Attachment
        > Are you set up for dual frequency operation?  That could cause what you are describing.  There is also the chance that your mobile might not have very good adjacent channel rejection and you're hearing a harmonic.

        Yep.  Both the RTrak and my voice rig are connected to NMO 2/70 antennas.

        > That does sound like the deviation is not correct.  When you say "picked up by local APRS network" how are you verifying that?  Direct decode local with an actual radio?   Looking online to see if it shows up?   If it's the latter, keep in mind the transmitter is only 350mW, so unless you are in the air or fairly close to a digipeater, I don't expect the RTrak-HAB to show up online. 

        The highly scientific method "B".  My baseline is the original setup, which was a 5-watt VX-170 w/ OT1+ and a 5/8 wave antenna mounted on the roof vs. the current RTrak on an NMO 2/70 mounted on the rear bumper of my truck.  Definitely a compromise installation, but I'm surprised at how many packets aren't making it to the iGate.  

        > If you don't have access to an RF service monitor, one method is to listen to other packets on the network and then try to adjust the RTrak-HAB to transmit at roughly the same audible level. 

        I'll give that method a try - I know what my RTrak sounds like from listening carefully for the corner peg packet when I turn, and it's a bit quiet.  I'll bump the audio up and see if it improves.

        Thanks!

      Your message has been successfully submitted and would be delivered to recipients shortly.