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

Overloading impact of a 2nd transmitter for tracker vs my primary mobile?

Expand Messages
  • wmacris
    I m considering adding a 2nd radio connected to a tracker, and the radio will be set at 5 watts output which is the minimum I can go for this radio. I assume
    Message 1 of 8 , May 28 7:11 AM
    • 0 Attachment
      I'm considering adding a 2nd radio connected to a tracker, and the radio will be set at 5 watts output which is the minimum I can go for this radio. I assume this will cause overloading of my existing installed mobile (the degree of this is to be determined). Lacking any experience with running a 2nd radio in-vehicle, I am curious how well such a setup is working out for others? Would anyone mind sharing how they have set up their mobile gear and how it's doing in these circumstances? My setup would be an FT-8800 (main) and icom 207h (tracker) both to 1/4 wave dual-band antennas.

      Thanks, Willie Macris / AC0UK
    • Jason KG4WSV
      ... Practically, this is pretty much exactly the arrangement you get with a Kenwood D7x0 mobile running APRS. I have mine set to TX APRS even if squelch is
      Message 2 of 8 , May 28 7:47 AM
      • 0 Attachment
        On Tue, May 28, 2013 at 9:11 AM, wmacris <wmacris@...> wrote:
        > 2nd radio in-vehicle, I am curious how well such a setup is working out for others?


        Practically, this is pretty much exactly the arrangement you get with
        a Kenwood D7x0 mobile running APRS. I have mine set to TX APRS even
        if squelch is open, so occasionally I get a <1s blanking of the
        received audio. I haven't found it to be a problem.

        -Jason
        kg4wsv
      • Patrick Wood
        The trick is to adjust your physical antenna spacing so that they end up in each other s null zones where ERP is minimal.. You will still get a bit of
        Message 3 of 8 , May 28 7:58 AM
        • 0 Attachment
          The trick is to adjust your physical antenna spacing so that they end up in each other's null zones where ERP is minimal..  You will still get a bit of de-sense, but it will be better then not and less likely to blow out your receiver..  should be one around 19 inches if memory serves....

          p


          On Tue, May 28, 2013 at 10:11 AM, wmacris <wmacris@...> wrote:
          I'm considering adding a 2nd radio connected to a tracker, and the radio will be set at 5 watts output which is the minimum I can go for this radio. I assume this will cause overloading of my existing installed mobile (the degree of this is to be determined). Lacking any experience with running a 2nd radio in-vehicle, I am curious how well such a setup is working out for others? Would anyone mind sharing how they have set up their mobile gear and how it's doing in these circumstances? My setup would be an FT-8800 (main) and icom 207h (tracker) both to 1/4 wave dual-band antennas.

          Thanks, Willie Macris / AC0UK




          ------------------------------------

          Yahoo! Groups Links

          <*> To visit your group on the web, go to:
              http://groups.yahoo.com/group/tracker2/

          <*> Your email settings:
              Individual Email | Traditional

          <*> To change settings online go to:
              http://groups.yahoo.com/group/tracker2/join
              (Yahoo! ID required)

          <*> To change settings via email:
              tracker2-digest@yahoogroups.com
              tracker2-fullfeatured@yahoogroups.com

          <*> To unsubscribe from this group, send an email to:
              tracker2-unsubscribe@yahoogroups.com

          <*> Your use of Yahoo! Groups is subject to:
              http://docs.yahoo.com/info/terms/


        • Randy Love
          I have a separate APRS radio running 10 W in the wife s car along with her primary voice radio. There is the blanking when a posit is sent, usually much less
          Message 4 of 8 , May 28 7:58 AM
          • 0 Attachment
            I have a separate APRS radio running 10 W in the wife's car along with her primary voice radio. There is the blanking when a posit is sent, usually much less than a sec as we use compressed posits. She hasn't griped much about it, so it isn't that bad. I also have a second 2m radio on voice for analog and D-star. The D710 is my primary APRS and voice radio. I experience the less than 1 sec desense on the IC-2200, but since it is only during posits, it's not that much of an issue. 

            The main thing that will determine if it will bother you or not is if you have the beaconing set to occur too frequently. If properly set, it shouldn't be a big issue for you.

            73,
            Randy
            WF5X


            On Tue, May 28, 2013 at 10:47 AM, Jason KG4WSV <kg4wsv@...> wrote:
             

            On Tue, May 28, 2013 at 9:11 AM, wmacris <wmacris@...> wrote:
            > 2nd radio in-vehicle, I am curious how well such a setup is working out for others?

            Practically, this is pretty much exactly the arrangement you get with
            a Kenwood D7x0 mobile running APRS. I have mine set to TX APRS even
            if squelch is open, so occasionally I get a <1s blanking of the
            received audio. I haven't found it to be a problem.

            -Jason
            kg4wsv


          • Curt, WE7U
            ... I m not sure how much my info will help. This may just confuse the matter but I ll give you what I _think_ I know: I ve been running a Kenwood TM-261A in
            Message 5 of 8 , May 28 8:13 AM
            • 0 Attachment
              On Tue, 28 May 2013, wmacris wrote:

              > I'm considering adding a 2nd radio connected to a tracker, and the radio will be set at 5 watts output which is the minimum I can go for this radio. I assume this will cause overloading of my existing installed mobile (the degree of this is to be determined). Lacking any experience with running a 2nd radio in-vehicle, I am curious how well such a setup is working out for others? Would anyone mind sharing how they have set up their mobile gear and how it's doing in these circumstances? My setup would be an FT-8800 (main) and icom 207h (tracker) both to 1/4 wave dual-band antennas.

              I'm not sure how much my info will help. This may just confuse the matter but I'll give you what I _think_ I know:

              I've been running a Kenwood TM-261A in my Jeep as the tracker radio. I started with a TT1 TNC, then went to a TT2, OT1, and now running a T2. I'm running two 10AWG wires from the battery, both fused at the battery end, to an APO2 automatic power-off device, then to a Saratoga power panel, then to the aprs tracker box. The antenna is on the driver's side hood and is a 5/8 wave 2-meter. I tend to run medium power on the TM-261A, so that's 15 or 20W.

              On the roof I have two drilled NMO mounts, each with a Larsen 1/4 wave on them which I can use for 2m or 440, and a mag-mount 5/8 wave 220 larsen. My voice rigs always go to antennas on the roof.

              What I _think_ I've noticed is that if I'm talking on 2M, my tracker doesn't get out as well. I haven't decided yet whether this also happens when I'm talking on 220 or 440, but I believe it does. This would tend to lead me towards thinking it's a power problem rather than a desense problem, but doesn't rule it out. If it's desense, then I might be transmitting at the same time as others, which would tend to make me heard less.

              If I install my tri-band rig downstream of the APO2, the APO2 doesn't work properly. I redo the power wiring in that case and put the tri-band radio upstream of the APO2, the APRS tracker box downstream of it: I just have to remember to absolutely make sure the rig is off when I shut down so I have a battery left for starting the Jeep.

              What I was/am most worried about is blowing up one of the receivers by transmitting with too much power, too close. I had a friend (now SK) who had that happen once or twice, and he had to repair or replace radio front-ends. With the slight vertical separation I have between the hood and roof antennas, and with medium instead of high power for APRS, I believe I've avoided that problem so far (for many years!), but it's also possible that I may have partially damaged the receiver front-end by now. If you have two antennas in physical proximity to each other and running higher power on at least one, other radio receivers in the same vehicle are at risk for that.

              Disclaimer: I'm NOT an RF engineer so take the above with a grain of salt.

              --
              Curt, WE7U. http://wetnet.net/~we7u
              APRS Usage Pages: http://wetnet.net/~we7u/usage.html
            • Curt, WE7U
              ... I should have mentioned in my prior post that I also experience momentary desense on a voice rig, and sometimes a burst of noise from the APRS packet
              Message 6 of 8 , May 28 8:28 AM
              • 0 Attachment
                On Tue, 28 May 2013, Randy Love wrote:

                > I have a separate APRS radio running 10 W in the wife's car along with her
                > primary voice radio. There is the blanking when a posit is sent, usually
                > much less than a sec as we use compressed posits. She hasn't griped much
                > about it, so it isn't that bad. I also have a second 2m radio on voice for
                > analog and D-star. The D710 is my primary APRS and voice radio. I
                > experience the less than 1 sec desense on the IC-2200, but since it is only
                > during posits, it's not that much of an issue.

                I should have mentioned in my prior post that I also experience momentary desense on a voice rig, and sometimes a burst of noise from the APRS packet depending on the frequency I'm listening to. I'm running compressed posits and SmartBeaconing(tm), so it's not a big issue (short packets and not happening all that often). I lose a syllable sometimes when listening. If I'm on 220 or 440 this doesn't happen at all.

                --
                Curt, WE7U. http://wetnet.net/~we7u
                Windows ate my homework!
              • James Ewen
                ... If you are thinking your 2 meter voice transmissions are desensing the digipeaters from receiving your APRS packets, that would be a bad conclusion. When I
                Message 7 of 8 , May 28 5:27 PM
                • 0 Attachment
                  On Tue, May 28, 2013 at 9:13 AM, Curt, WE7U <curt.we7u@...> wrote:

                  > What I _think_ I've noticed is that if I'm talking on 2M, my tracker doesn't get
                  > out as well. This would tend to lead me towards thinking it's a power problem
                  > rather than a desense problem, but doesn't rule it out. If it's desense, then I
                  > might be transmitting at the same time as others, which would tend to make
                  > me heard less.

                  If you are thinking your 2 meter voice transmissions are desensing the
                  digipeaters from receiving your APRS packets, that would be a bad
                  conclusion. When I read this first I thought you were thinking one
                  transmitter was densensing the other transmitter, which can't happen
                  because desense is a receiver phenomenon.

                  However, I think you're talking about your 2 meter voice transmissions
                  are blocking the RX on the APRS unit, and it can't tell if the APRS
                  channel is clear, so it ends up transmitting in the blind, and
                  possibly colliding with other packets out there.

                  You'd have to be listening to the APRS channel from another location
                  that is able to hear in the clear, and then figure out if your APRS
                  station is transmitting on top of others... not an easy task, but a
                  definite possibility.

                  --
                  James
                  VE6SRV
                • Curt, WE7U
                  ... Correct. ... Yep. In our area there s so much traffic that if it was happening, it would definitely affect the percentage of transmissions that made it.
                  Message 8 of 8 , May 28 7:41 PM
                  • 0 Attachment
                    On Tue, 28 May 2013, James Ewen wrote:

                    > However, I think you're talking about your 2 meter voice transmissions
                    > are blocking the RX on the APRS unit, and it can't tell if the APRS
                    > channel is clear, so it ends up transmitting in the blind, and
                    > possibly colliding with other packets out there.

                    Correct.


                    > You'd have to be listening to the APRS channel from another location
                    > that is able to hear in the clear, and then figure out if your APRS
                    > station is transmitting on top of others... not an easy task, but a
                    > definite possibility.

                    Yep. In our area there's so much traffic that if it was happening, it would definitely affect the percentage of transmissions that made it. I think it might be tricky to do what you're talking about, w/o a TNC decoding the packets right by that other party. Even then it would be difficult.

                    --
                    Curt, WE7U. http://wetnet.net/~we7u
                    APRS Wiki: http://info.aprs.net/
                  Your message has been successfully submitted and would be delivered to recipients shortly.