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Thread: USB Dongle vs. SBS-1/1er

  1. #21
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    mounting the antenna on a temporary timber mast sounds good, but you might not want the actual receiving bit of the antenna nailed to the wood since the water content of the wood may block some of the signal - construction of some sort of stand-off would probably fix that.

    Now I'm trying to remember stuff about coaxial cables. The signal doesn't actually pass along the conductors it reflects backwards and forwards between the inner and outer as passes through the dielectric (this is where the velocity factor comes in). Now you can put bends in the cables as long as they are gentle enough that the signal continues to be reflected around the bend - but if you kink it the signal will get attenuated. You also want any connections to other cables not to cause reflections of any of the precious signal back up the wire - this is why joins are so bad. but you also want to try to ensure that where you do join that the cables (add tails) - as far as possible - are of similar impedance to the rest of the cable to minimise the reflections.

    Domestic TV satellite receivers have an LNB at the dish to down-convert the signal frequency of the TV signal from 10Ghz to 1 - 2Ghz (similar frequencies to ADSB) - the down conversion is done just to make it easier to handle the signal without waveguides etc.

    To me it seems more and more sensible to put the dongle + Raspberry Pi actually on the top of the mast in a sealed box ... the CAT5 cable should be good for up to 100m without effort. I doubt that the Pi itself would cause itself heat problems - but solar heat might ... so maybe put the sealed box into a ventilated box to act as a sun shield.

  2. #22
    Captain Birdie's Avatar
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    Quote Originally Posted by fungus View Post
    I was just pulling your leg Birdie (an aussie way of saying I was sharing a joke with you), I'll see what I can do for you
    BTW it wasnt a slur on you Birdie when I said it's really simple- it needs to be for me to be able to do it and I apologise if it's difficult to follow.
    Regards,
    Gregg
    Why take things so serious ?

    Have a Foster Beer and cool down. wahahahaaaa
    F-WSSS1 - Cats refused to Pee & Pooh on RadarBox - Running a FR24 Receiver & DVB-T Dongle 24/7 to piss off The Chief Thief.

  3. #23
    Captain fungus's Avatar
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    Quote Originally Posted by Birdie View Post
    Why take things so serious ?

    Have a Foster Beer and cool down. wahahahaaaa
    Birdie,
    I think you're losing something in the translation I was having a laugh with you mate.
    Regards,
    Gregg

  4. #24
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    Thanks Gregg (apologies for calling you Oblivian) and to you Peter for your imput.

    Well tonight (18:00BST) when I got in from work. I set about constructing my timber mast using 2"x1" which has been weather treated by the manufacturer. I used 1 length of 4.9mtrs and 2.1mtrs from another length, making my total of 7mtrs -approx 22ft.

    I then screwed an aluminium "L" shaped bracket to the very top of the mast and placed my USB Dongle antenna onto that using clear silicone to hold it in place and also make it waterproof.

    I ran the supplied antenna lead into a weatherproof box I already had and placed the USB dongle, antenna lead and female end of my 10mtr Active USB cable into this box and screwed that just below the antenna. Then using cable clips to neatly run the USB cable down the timber mast.

    Now the fun began - to attempt to lift the mast and setup into place from laying on the floor to standing vertical (the mast not me lol).

    Yes it flexed slightly but I just managed it on my own. I then drilled timber to wall in several places and we're now go to go, with the antenna now above my roof - 30ft off the floor.

    Remember, this is only a temporary setup to see how it works for when I use high quality cable and a decent antenna but as everything is now drilled, it's just a matter of swapping cable and antenna.

    Anyways, connected USB to my PC and fired up the software.

    So, prior to the mast construction tonight, I achieved a max range of 75nm (86miles) with fragmented data.

    With my newly constructed mast. Tonight I achieved 174nm (200miles) and no fragmented data.

    For those living in England. I tracked flight No. NVD206 from mine in Dudley, West Midlands, right across the Irish Sea and finally lost signal when the A320 was inbetween Belfast and Larne. Yay :-)

    Then UAE20 popped up taking off from EGCC (Manchester Apt) and I picked that up when it was climbing through 5,000ft.

    I'm totally surprised in this vast improvement. If I achieve this now with just a USB Dongle and its supplied antenna. Could I even better that with 400 cable and a decent antenna?

    I'm unable to pickup EGLL (London Heathrow) as my Chimney just happens to be obstructing me now. I would need another 2mtrs to clear that and 1: My back yard isn't long enough to lay it all out and 2: I think the timber would snap when trying to lift it all.

    But at least I'm clearing all other roofs and tree tops :-) WIN

  5. #25
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    Yep, it's working just fine and it proves my RX is more stable now, as for the first time since feeding FR24 (May 4th), I finally capture an aircraft with my Radar tagged to it.

    I am approx 30 miles West of Birmingham Airport (EGBB) and I capture this Monarch on finals - Monarch Hour again lol

    image.jpg
    T-EGBB16

    Hardware: NooElec DVB-T2 Dongle, Raspi Pi2 Mod B, 6dB Collinear Antenna, Nevis Pre-Amp & 1090mhz SAW Filter, 9mtrs WF100 Cable and 28ft Mast.
    Software: Rasbain Jessie Lite, FR24 Feeder, Dump1090mutab and VRS.
    Stats for Mar 18, 2016. Uptime:100%. Aircraft seen:2,012. Positions Reported:486,817. Maximum Distance:243nm (Stats provided by FR24)

  6. #26
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    Responder,
    Glad to see you getting results and I think Oblivian and others have been far more helpful than I so no worries there. Just one word on your setup. I had my mast recently re-installed by professionals as the original put up by dodgy brothers (myself and my son) spectacularly came down in a storm late last year and could have done a lot of damage- we were very lucky. I'm only now back on the air to a reasonable extent so it doesnt always pay to do ALL the bits yourself.
    Good luck and keep on going mate.
    Regards,
    Gregg

  7. #27
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    Good going - it's nice to see someone getting great results using minimal equipment. In your position I think I'd be tempted to keep the "mast head dongle" and forget the expensive down lead - just needs a safe mast and a safe and easy way to access the equipment there ... and to sort out a better antenna. One benefit is that you have the second dongle that you can use to make up and try antennas on and only put them at the mast head once you have a likely suspect.

    I did have good results from a simple dipole (see http://antirez.com/news/46 - just make a neater job of it) - in your case you would mount it vertically at the end of your bracket ... My guess this would give a good step up in range ... maybe 20-40% (try it with the other dongle), and do try the co-linear ... the idea with that is that the more element you have the more your reception area becomes like a ring doughnut ... so much so that you may receive signals from 200Km away but not get the planes overhead.

    I remember reading somewhere about one of the guys in Bulgaria who had four (or more) antennas in-front of focusing reflectors giving a vast range each ... and he needed a simple antenna just to fill in the hole in the middle to get the local stuff.

  8. #28
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    Quote Originally Posted by peterhr View Post
    I remember reading somewhere about one of the guys in Bulgaria who had four (or more) antennas in-front of focusing reflectors giving a vast range each ... and he needed a simple antenna just to fill in the hole in the middle to get the local stuff.
    Thats Miro, the maker of the microadsb (my first receiver). He use to have a picture of it on his website

    It was also a few thousand dollars

  9. #29
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    http://www.microadsb.com/

    This? have a look under ads-b receivers. 999euros.

    a very nice and interesting findings on your venture into getting a mast head dongle for ads-b Responder! Mike at NZ radar did something similar with a 9db gain DPD antenna+ dongle but the result wasn't what we expected - poorer performance. you can have a look at his website if you haven't come across it. just google nzradar.
    Last edited by North Borneo Radar; 2013-07-03 at 14:17.

  10. #30
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    Hi all,

    Gregg: ooh that wasn't good to hear about your mast coming down last year but glad you got it sorted.
    I am quite confident that my setup won't come down even in high wind. 1: My mast is screwed to the wall in three places. 2: I created a "n" bracket which I have put onto the mast which hooks onto the cast iron guttering to stop it swaying.

    The attached picture is of my mast head. Please note that this guttering is about 30ft high lol.

    image.jpg

    Peter: I agree with you and I'm happy with my dongle and Active cable but may look at other antennas. I might give the Dipole a go, considering I have a long enough mast to mount it vertically lol.

    I actually have four dongles. Two in use and two for Backup/Replacements and like you say, I can use these until I find an antenna I'm happy with and then put that up on my mast :-)

    Oh and tonight, I was tracking 62 Aircraft as apposed to my 40 prior to constructing my mast. Probably just as well I cannot pick up Heathrow, as PC may crash under the data streaming in lol
    Last edited by Responder; 2013-07-03 at 23:13.
    T-EGBB16

    Hardware: NooElec DVB-T2 Dongle, Raspi Pi2 Mod B, 6dB Collinear Antenna, Nevis Pre-Amp & 1090mhz SAW Filter, 9mtrs WF100 Cable and 28ft Mast.
    Software: Rasbain Jessie Lite, FR24 Feeder, Dump1090mutab and VRS.
    Stats for Mar 18, 2016. Uptime:100%. Aircraft seen:2,012. Positions Reported:486,817. Maximum Distance:243nm (Stats provided by FR24)

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