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  • I have left plane plotter on for a few hours, taken a screen shot of the tracks left by a/c, printed it and gone up to where my antenna currently sits, there are visible obstructions which are causing signal loss for more than a few minutes at a time.

    SO, I'm still going ahead with 6m mast on my roof. However it now appears that may not happen until one day next week.
    F-YBNA2

    Comment


    • Originally posted by Lancair70 View Post
      I have left plane plotter on for a few hours, taken a screen shot of the tracks left by a/c, printed it and gone up to where my antenna currently sits, there are visible obstructions which are causing signal loss for more than a few minutes at a time.

      SO, I'm still going ahead with 6m mast on my roof. However it now appears that may not happen until one day next week.
      I certainly hope that helps since you're filling in something of a gap we had up that way south of BNE towards SYD. I'm currently having a similar job done on my antenna and hopefully will be able to pick up aircraft well the other side of Tamworth/Armidale by the time it's finished. I wish I could get rid of a few more gum trees around here though as surprisingly they can block a lot of signals. Unfortunately it might take a storm or two to do so as the local council still have a tree preservation policy but gum trees and houses just dont mix as has been witnessed here around SYD by the recent bushfires.

      Regards,
      Gregg
      Last edited by fungus; 2014-01-08, 03:18.
      YSSY2/T-YSSY4 [SBS-1 Basestation w/- SSE-1090 SJ Mk2 Antenna (Thanks Delcomp) ] [Uniden UBCD996T w/- 16 element Wideband Discone VHF/UHF Antenna, and tuned 108MHz-137MHz Airband Antenna] [Trialing a home-brew 1090MHz collinear antenna]

      Comment


      • Originally posted by Lancair70 View Post
        I have left plane plotter on for a few hours, taken a screen shot of the tracks left by a/c, printed it and gone up to where my antenna currently sits, there are visible obstructions which are causing signal loss for more than a few minutes at a time.

        SO, I'm still going ahead with 6m mast on my roof. However it now appears that may not happen until one day next week.
        Make sure you got omit/delete aircraft quite short. Else PP predicts and leaves trails still giving false readings
        Posts not to be taken as official support representation - Just a helpful uploader who tinkers

        Comment


        • Originally posted by Oblivian View Post
          Make sure you got omit/delete aircraft quite short. Else PP predicts and leaves trails still giving false readings
          Yep I did that for this exercise. Very interesting to see just how long FR24 keeps the a/c visible after it's left my coverage heading east out to sea.

          There's a 2nd reason for going for the taller mast, Id like to get a VHF aerial for a scanner one day. I have a handheld Uniden now but would ultimately like a decent setup.
          F-YBNA2

          Comment


          • You can DIY those up too
            Posts not to be taken as official support representation - Just a helpful uploader who tinkers

            Comment


            • I'm quite happy with the FR24 setup as it is, just get it higher to have clearer view.

              Any info about which or how to for antenna/s for VHF airband use would be much appreciated.
              F-YBNA2

              Comment


              • Quarter wave calculators all point to 22 inches, or 56cm centre, with similar length radials for groundplane. But be wary at the lower end of the scale SWR can start to take effect
                Posts not to be taken as official support representation - Just a helpful uploader who tinkers

                Comment


                • Originally posted by Lancair70 View Post
                  I'm quite happy with the FR24 setup as it is, just get it higher to have clearer view.

                  Any info about which or how to for antenna/s for VHF airband use would be much appreciated.
                  I noticed in an earlier post that you have a scanner. If you're only wanting to listen to airband you can either make a simple airband antenna or buy a tuned airband antenna for external mounting on a mast which is what I did. I've also got a discone for my Uniden desktop scanner (originally used for the ADS-B receiver) but I let myself down badly with choice of cable. I used RG58 which is about the size of a chopstick (nice and small, very easy to work with and get into tight places like slipping under roof tiles) but it's got far higher losses than many other cables and I definately wouldnt recommend it. Nor would I recommend the discone for ADS-B just while I'm on that subject. The discone cost just over $100 Aussie and the tuned airband about half that if not less. I'm hoping to soon have the cables replaced and elevate the discone and airband antennas a few metres and see if I can improve reception.
                  I now use a dedicated 1090SJ (thanks again David) for the ADS-B receiver and either of the two antennas described for ATC (Air Traffic Control). I'm about 20NM from SYD and the only frequencies I cant pick up are ground and tower (I can hear the aircraft though on tower frequency). Surprisingly I can also pick up clearance delivery, which gives an indication of departutre tracks and is handy for taking pics of departing aircraft.

                  Whichever way you go chat to the guys on here as to how best to do it or come on to the chat and ask, although the chat isnt always the best option as guys arent on all the time. I only wish I'd done so before I installed my setup but I did that before I came upon FR24. There's quite a few guys on here who are very good with antennas and cable preferences. I'm a novice and there's plenty with far more expertise than I'll ever have on here. There's also plenty of websites that have comparison tables for the various cable types, e.g. http://www.w4rp.com/ref/coax.html. Mr Google can help as well. A good setup will open up a whole new experience as far as what you will be able to listen to and there's nothing better than watching aircraft on FR24 (and/or the ADS-B receiver) and listening to ATC, unless you like Magnum ice creams.

                  Regards,
                  Gregg
                  Last edited by fungus; 2014-01-09, 06:15.
                  YSSY2/T-YSSY4 [SBS-1 Basestation w/- SSE-1090 SJ Mk2 Antenna (Thanks Delcomp) ] [Uniden UBCD996T w/- 16 element Wideband Discone VHF/UHF Antenna, and tuned 108MHz-137MHz Airband Antenna] [Trialing a home-brew 1090MHz collinear antenna]

                  Comment


                  • Thanks for that info Greg.

                    My antenna installation guy is stuffing me around, first off tells me 6m, no worries, then arrives with a 3m and says 'it'll do'. I said No, we agreed on a price for 6m!
                    Anyway he calls me back on friday morning and says he can only get 4.5m sections now ?

                    I'm going to call someone else I think.
                    F-YBNA2

                    Comment


                    • Originally posted by Lancair70 View Post
                      Thanks for that info Greg.

                      My antenna installation guy is stuffing me around, first off tells me 6m, no worries, then arrives with a 3m and says 'it'll do'. I said No, we agreed on a price for 6m!
                      Anyway he calls me back on friday morning and says he can only get 4.5m sections now ?

                      I'm going to call someone else I think.
                      Yeah, he is having a go at you....You can buy 25mm x 1.6mm wall thickness gal tube for about $5.00 per metre on Ebay + delivery. Bunnies sell it, but in set lengths of 1 metre and 3 metres, though more expensive from them or if not inclined to do the work your self, then get another quote. Job is not "that" difficult for an antenna guy willing to get a 6 metre length on the roof.

                      Regards
                      Geoff

                      Comment


                      • Just sitting here this afternoon and noticed an aircraft with an unusual track heading this way. It was VH-PPV, identifying as Airorescue and it took quite an interest in the Kempsey area. If it was Polair I'd say it was looking for sticky wed plantations<grin>

                        Ray
                        vk2tvScreenshot.png

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                        • Originally posted by fungus View Post
                          Just spoke with an antenna expert a few days ago about that very issue with LMR400. He recommended RG213 if the cable run isnt too long as it's the same size as LMR400 but much easier to work with as it's more pliable but obviously not as good as far as losses. There you go, Oblivian is far more familiar with these things than I am (see post above).

                          Regards,
                          Gregg
                          Hi All,

                          The subject of cable loss is often discussed and often misunderstood, even by people who should know better. Yes, cable loss CAN be important but it needs to be taken into perspective, the loss figures in isolation being somewhat less important than they might seem to be.

                          First, my qualifications. I'm retired now but I worked in communications for thirty years and my hobby of radio has existed for sixty years. Professionally I worked with large radio base station installations to 500MHz and in my hobby I engaged in frequencies to 3.5GHz. I have used coaxial cables that vary in size from about 1/8" in diameter, all the way to 1.25" diameter Heliax.

                          Let's look at some typical loss figures for commonly used coaxial cable.

                          LMR400seems to be the bench mark for ADSB but there are much better and much worse cables.

                          The following table lists loss figures per 100' at 1090MHz, in descending order of loss.

                          RG58 17.4dB Belden (arguably the best cable available) list three variations with a 3dB/100' difference in loss
                          RG213 8.6dB Beldon figure - beware of cheap imitations
                          LMR400 4.3dB
                          10D-FB 4.0dB 10D-FB is a semi-flexible cable about 20mm OD. Beware the Chinese version with horrendous loss.
                          LDF4-50 2.33dB This is "hardline", 20mm dia approx, with a corrugated copper outer conductor. Bending radius is limited. Both cable and connectors are very expensive.

                          Now the practicalities. Regardless of the length of the cable run, and ignoring RG58, if that run is predominantly vertical none of those loss figures should be of great concern because, antenna height gain will compensate for cable loss. Yep, a sweeping statement but reasonably correct. What one needs to consider is not the loss figure of a particular cable. Rather, consider the difference in loss/100' between the "best" cable and the cable you can afford or the cable you can work with at your installation. Compare LMR400 with RG213 and the difference in loss is about 4dB/100ft. In a typical installation of, say 50', the difference would be 2dB and this would be almost unnoticeable on performance. I know, the "experts" say every decibel (dB) is important but in reality that is crap. In a laboratory situation the difference can be measured, in a practical installation nobody would be able to pick the difference.

                          Here's great example of what I'm getting at. This is about an amateur radio repeater in the US where the antenna is 900' above ground on a 1000' TV tower. The Heliax (hardline) feedline is 1400' long! The transmitter produces 40W but only 2W gets to the antenna, that's 13dB loss. Because of the 900' height gain the repeater covers three US states. That same principle applies for adsb. Get the antenna as high as you can, even if you can't afford the best coaxial cable. If a roof mount is all you can achieve, even with a 50' mast the difference between RG213 and LMR400 will not be noticed. Station performance depends on line of site coverage and the higher the antenna the further away is the horizon (actual range is slightly further due to diffraction in the atmosphere).

                          What would I use for an antenna up to 50' above ground? I have RG213, 10D-FB and LDF4-50 available. For ease of installation I would likely choose RG213 but because I have 10D-FB I would probably use it with a flexible tail at the rx.

                          Keep away from RG58 and most of us will be able to live comfortably witrh all the other cables referenced.

                          Ray
                          vk2tv
                          Now
                          officially T-YPMQ1

                          Comment


                          • Originally posted by Mike View Post
                            New FR24 receivers
                            F-YPPH5 activated in Perth, Australia
                            Perth sure is getting quite a number of FR24 receivers...

                            Comment


                            • Hi all,
                              I have joined the FR24 fraternity , my equipment has arrived (thank you FR24 for approving me) and all is installed.
                              I seem to have a slight issue as in when I turn the unit on all goes well for about 5-7 minutes then my internet slows to a stop. I check my firewall and there is a severe packet loss at around 42%. I turn off the unit and my internet comes good.
                              Has anyone else experienced this?

                              Regards
                              Chris...
                              http://belconnenweather.net
                              http://scanact.net
                              FR24 alias - F-YSCB1

                              Comment


                              • Originally posted by scanACT View Post
                                Hi all,
                                I have joined the FR24 fraternity , my equipment has arrived (thank you FR24 for approving me) and all is installed.
                                I seem to have a slight issue as in when I turn the unit on all goes well for about 5-7 minutes then my internet slows to a stop. I check my firewall and there is a severe packet loss at around 42%. I turn off the unit and my internet comes good.
                                Has anyone else experienced this?

                                Regards
                                Chris...
                                Hi, best to contact FR24 at this email address : support@FR24.com regarding your issue.

                                Comment

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