Page 3 of 13 FirstFirst 12345 ... LastLast
Results 21 to 30 of 128

Thread: 3 EASY ANTENNAS FOR BEGINNERS

  1. #21
    Passenger
    Join Date
    Aug 2015
    Posts
    13
    Cool! Thank you very much! Cheers from Brazil!


    Enviado do meu iPhone usando Tapatalk

  2. #22
    Captain abcd567's Avatar
    Join Date
    Sep 2013
    Location
    Toronto CYYZ
    Posts
    2,691
    Quote Originally Posted by rodeo View Post
    Here's my adaptation of the cantenna design; from memory it was a can of pineapple pieces before it became an antenna

    Diameter is 80mm, sides are 90mm. Probably not the most ideal dimensions but seems to work OK.

    SMA bulkhead connector on top, cable exits via the 16mm plastic conduit supporting it all.
    Cool!

    (1) Innovative to use a different type of connector. I used F-barrel connector because of its low cost and universal availability. Almost all types connectors will perform more or less same.

    (2) Dia 80mm is ok. I have tried cans of diameter 20mm to 100 mm. Cans with dia less than 66 mm (The 330/350mL Drink Can) give inferior result. Cans from 66 mm to 100 mm dia gave more or less same results.

    (3) Height (sides) 90 mm is not ideal. This dimension is not very critical, but does affect performance. The best results are obtained with 69 mm (1/4 wavelength).

    NOTE: I could not get a 20 mm dia Can, so I used a 3/4 inch (20 mm) dia copper water pipe with end-cap.

    Last edited by abcd567; 2015-10-30 at 22:55.

  3. #23
    Passenger
    Join Date
    Aug 2015
    Posts
    13
    Nice!! Cheap and easy!


    Enviado do meu iPhone usando Tapatalk

  4. #24
    Passenger
    Join Date
    Jan 2014
    Location
    Somerset
    Posts
    8
    Quote Originally Posted by abcd567 View Post
    DC power to Amplifier is supplied over the same coax which carries the 1090 Mhz signal from antenna to receiver. You will need a ac/dc adapter and a power inserter.

    Just out of interest do you need to use a DC Blocker?
    T-EGGD11 -- RTL2832U / R820T+ Raspberry Pi2 + Dump1090, FR24, PF. Cantena 248Mi 0ft ASL
    T-EGGD21 -- RTL2832U / R820T+ Raspberry Pi + Dump1090, FR24, PF. Home made COCO 257Mi 600ft ASL

  5. #25
    Captain abcd567's Avatar
    Join Date
    Sep 2013
    Location
    Toronto CYYZ
    Posts
    2,691
    Quote Originally Posted by EGGD11 View Post
    Just out of interest do you need to use a DC Blocker?
    Sorry for late reply.

    DC Blocker is essential only for antennas which have a short. DC Blocker is not required for Cantenna and Spider, as there is no short in these antennas. However there is no harm if DC Blocker is installed.

    Check continuity between core and shield at the feed point of any antenna by a multimeter. If it shows continuity (buzzer/light), there is a short inside. In this case a DC Blocker is a must. I have once fried my power inserter when I connected a shorted antenna without DC Blocker.

  6. #26
    Passenger K5TED's Avatar
    Join Date
    Dec 2015
    Posts
    36
    Lots of great antenna ideas here. The wonderful thing about 1090MHz is the antennas are very small. This allows lots of experimenting with little actual materials needed, unlike HF or even VHF antennas. At 1090, the cables and connectors are more elaborate and costly than the actual antenna materials.

    With experimention in mind, here's an antenna design that outperforms the supplied whip, and requires no more than a BNC barrel connector and a few cm of 24g solid copper wire, in this case, a strand from a piece of CAT5...

    The Delta Loop. This can be positioned and fed in many different configurations with varying pattern results:

    dll.jpg

    The orientation and feed methods:

    delta-loop.gif

    Basic design is using 10cm per side at this frequency. Check for "delta loop calculator" on the web for reference. There are many wire antenna possibilities that can be pressed into testing for 1090, including quads, loops, moxons, etc. .


    I found this commercial MaxRad RDS antenna on ebay for the princely sum of $8 USD. It is originally designed for 800MHz, but it was a simple matter to trim the radiator and radials down to 1090 :

    gpl.jpg

    These were still available as of today, so if you decide to try this antenna and want to trim it down, I took one completely apart and got the dimensions so you don't have to:

    1. Radiator is pressed in to the hardline center. DO NOT ATTEMPT TO TWIST AND REMOVE IT. Trim it in place. It protrudes 81mm from the center conductor (measured with cover off) Remove the black plastic bootie and trim accordingly from the tip. (13mm for a 68mm adjusted length)

    2. Ground Radials are 84mm long and threaded into the aluminum base ring, measured observing the three to 4 threads left exposed. Remove the black plastic bootie and trim accordingly from the tip. (16mm for a 68mm adjusted length)

    If you insist on taking it apart to see the guts, after the three radials are unscrewed and removed, the assembly slides out of the cover. It is a bit fiddly to get the threads all lined up when putting it back together. Remember this is aluminum, so be gentle.

    The antenna works well, in my estimation, set at about 25' in a window for now, can get up to 178 miles South and about 150 North. It'll be interesting to see how it does mounted in an enclosure outside with a clearer view to the East and West.


    I'm a newbie to ADS-B, but a longtime amateur radio hobbyist, so this is a refreshing new facet. Currently using a Noelec 820T2 RTL with an Intel Compute Stick, running Win 10Pro, Dump1090, Virtual Radar Server and feeding FR24. site is T-KSAT6

  7. #27
    Passenger skyspotter's Avatar
    Join Date
    Nov 2015
    Location
    SA Texas
    Posts
    42
    Quote Originally Posted by K5TED View Post
    Lots of great antenna ideas here. The wonderful thing about 1090MHz is the antennas are very small. This allows lots of experimenting with little actual materials needed, unlike HF or even VHF antennas. At 1090, the cables and connectors are more elaborate and costly than the actual antenna materials.

    With experimention in mind, here's an antenna design that outperforms the supplied whip, and requires no more than a BNC barrel connector and a few cm of 24g solid copper wire, in this case, a strand from a piece of CAT5...

    The Delta Loop. This can be positioned and fed in many different configurations with varying pattern results:

    dll.jpg

    The orientation and feed methods:

    delta-loop.gif

    Basic design is using 10cm per side at this frequency. Check for "delta loop calculator" on the web for reference. There are many wire antenna possibilities that can be pressed into testing for 1090, including quads, loops, moxons, etc. .


    I found this commercial MaxRad RDS antenna on ebay for the princely sum of $8 USD. It is originally designed for 800MHz, but it was a simple matter to trim the radiator and radials down to 1090 :

    gpl.jpg

    These were still available as of today, so if you decide to try this antenna and want to trim it down, I took one completely apart and got the dimensions so you don't have to:

    1. Radiator is pressed in to the hardline center. DO NOT ATTEMPT TO TWIST AND REMOVE IT. Trim it in place. It protrudes 81mm from the center conductor (measured with cover off) Remove the black plastic bootie and trim accordingly from the tip. (13mm for a 68mm adjusted length)

    2. Ground Radials are 84mm long and threaded into the aluminum base ring, measured observing the three to 4 threads left exposed. Remove the black plastic bootie and trim accordingly from the tip. (16mm for a 68mm adjusted length)

    If you insist on taking it apart to see the guts, after the three radials are unscrewed and removed, the assembly slides out of the cover. It is a bit fiddly to get the threads all lined up when putting it back together. Remember this is aluminum, so be gentle.

    The antenna works well, in my estimation, set at about 25' in a window for now, can get up to 178 miles South and about 150 North. It'll be interesting to see how it does mounted in an enclosure outside with a clearer view to the East and West.


    I'm a newbie to ADS-B, but a longtime amateur radio hobbyist, so this is a refreshing new facet. Currently using a Noelec 820T2 RTL with an Intel Compute Stick, running Win 10Pro, Dump1090, Virtual Radar Server and feeding FR24. site is T-KSAT6
    Are you using the Ebay Antenna? BTW i just notice got a new neighbor on KSAT QTH.. am feeding as T-KSAT5. Looks like youre near the airport coz youre tracking most of in-outbound planes. 73s.

  8. #28
    Passenger K5TED's Avatar
    Join Date
    Dec 2015
    Posts
    36
    Quote Originally Posted by skyspotter View Post
    Are you using the Ebay Antenna? BTW i just notice got a new neighbor on KSAT QTH.. am feeding as T-KSAT5. Looks like youre near the airport coz youre tracking most of in-outbound planes. 73s.

    Yes, I am. Tried a homebrew groundplane, a three element collinear, and a Franklin design, and keep coming back to the modified Maxrad from eBay. It gets the best overall coverage. Can't beat it for about $11 shipped. Just put on the FlightAware filter and increased the message count. Running it indoors in a North facing window for now til I get the outdoor enclosure built and mounted.

    I'm near Blanco and Wurzbach.

  9. #29
    Passenger skyspotter's Avatar
    Join Date
    Nov 2015
    Location
    SA Texas
    Posts
    42
    Quote Originally Posted by K5TED View Post
    Yes, I am. Tried a homebrew groundplane, a three element collinear, and a Franklin design, and keep coming back to the modified Maxrad from eBay. It gets the best overall coverage. Can't beat it for about $11 shipped. Just put on the FlightAware filter and increased the message count. Running it indoors in a North facing window for now til I get the outdoor enclosure built and mounted.

    I'm near Blanco and Wurzbach.
    No wonder youre picking most of AC coming from west approach. Am near Perrin Beitel and Starcrest Dr. Cool! am using homebrew Qwave antenna with amp powered with Directv power inserter and also with FA filter. Do you feed to FA?

  10. #30
    Passenger K5TED's Avatar
    Join Date
    Dec 2015
    Posts
    36
    Quote Originally Posted by skyspotter View Post
    No wonder youre picking most of AC coming from west approach. Am near Perrin Beitel and Starcrest Dr. Cool! am using homebrew Qwave antenna with amp powered with Directv power inserter and also with FA filter. Do you feed to FA?
    Presently feeding to FA, FR24 and PP and my own FRS site.

    Would be great if you would run PP to give a local MLAT MU/GS or feed raw to my PP site :-)

    BTW, the existing FR24 MLAT spots on the trainers buzzing around is fascinating.
    Last edited by K5TED; 2016-01-08 at 02:28.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •