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  • SlackDarren
    replied
    No there isn't. I used a Half liter plastic bottle, with some hot melt glue on the top. So when i pushed into the bottle it stuck to the inside top of the bottle. I then pushed some 15mm Plastic pipe in the bottom fitted lovely. then hot glued around the pipe and the bottle. Looks ugly but works a treat. Cable comes out through bottom pipe. Oh and also getting around 900 planes a day, previously using a quarter wave ground plane around 500.Thanks for your question.

    Leave a comment:


  • maltim
    replied
    [QUOTE=SlackDarren;n227993]Are these any good. image.png​[/QU

    Hi! Is there a cover for working outdoors and if not -how can I protect it from external influences?

    Leave a comment:


  • SlackDarren
    replied
    Are these any good. image.png

    Leave a comment:


  • abcd567
    replied
    Originally posted by SlackDarren View Post

    #1443 What is this program and where can I get it. Thanks

    It is called adsbScope




    Downloads

    Latest Version 2.7

    pepsi can halfwave dipole in radome-NO AMPLIFIER short (12 ft) Coax.jpg




    .

    Leave a comment:


  • SlackDarren
    replied
    Originally posted by abcd567 View Post
    Here are results of my 3 antennas WITHOUT AMPLIFIER, and short (12 feet) Coax from antenna to Receiver.
    As you can see, the Franklin & 5/8 wavelength Coil-Tuned are much inferior to Sleeved dipole when run WITHOUT AMPLIFIER.

    This shows that:
    (1) Half-wave Dipole is inherently tuned with SWR=1 if its two legs are cut at 69mm. This is very easy for any DIY hobbyist.
    (2) Franklin & coil tuned (and coco also) require tuning which depends on dimensions & alignments. Little errors caused by DIY hobbyist throw them far away from optimum. These can be best made accurately only in Factory environment with all jigs, tools, templates & sophisticated test equipment.


    Half wave Sleeved Dipole (Pepsi-can)
    [ATTACH=CONFIG]4594[/ATTACH]

    5/8 wavelength dipole with tuning/matching coils
    [ATTACH=CONFIG]4593[/ATTACH]

    4-element Franklin with Matching stub.
    [ATTACH=CONFIG]4592[/ATTACH]
    #1443 What is this program and where can I get it. Thanks
    Last edited by SlackDarren; 2025-01-23, 15:32.

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  • SlackDarren
    replied
    Wow what a interesting thread. Thanks.

    Leave a comment:


  • abcd567
    replied
    No need to cut the whip.
    Unscrew the whip and use a thin copper wire like one of 6 wires from a scrap network cable, or a thin steel tie wire like the one in first two photos below.

    Optimized Whip Steel Tie Wire.jpg




    Optimized Whip Steel Tie Wire-Dimensions.jpg


    Dimensions of Optimized Whip.png




    Use one of the many wires in a Scrap network cable





    category_5e_ethernet.jpg

    Last edited by abcd567; 2022-04-04, 04:03.

    Leave a comment:


  • Lufthansa
    replied
    20220403_180505.jpg


    Does anyone have an idea how I can shorten this antenna for 1090 MHz? Bought this antenna through Amazon a few years ago for some bucks, but it has performed / performs TERRIBLY....

    I don't know how to count the coils in the total length of the antenna (λ/4=6.88 cm or λ/2=13.75 cm). I've already read/searched a bit about coiled antennas/whips here in the forum, but didn't found a solution.

    I am grateful for any suggestion!
    Attached Files

    Leave a comment:


  • Bill@2020
    replied
    hello gentleman...
    i would like to show you my results of my development because of antennas. Years ago I started this development because of the unreliable ADS-B data during flying sharp u-turns, curves.
    The ads-b signal is generally vertical polarized. During flying curves the antenna is not vertical. Rod antennas and all other antennas on the market have all a vertical polarization.
    To avoid that problem I developed a new antenna which is very tiny, has a perfect pattern, can be used as sector antenna and no more filter is needed.
    attached I have a video which I made 2 days before ...the result was perfect and follows all simulated parameter ....

    Have fun

    Bill2002

    Sorry I have made comments in german....but you will understand :-/

    Leave a comment:


  • bg6snj
    replied
    Originally posted by abcd567 View Post
    Same wire data as above, simulated in software MMANA-GAL, gives Gain = 7.35 dBi, & very high SWR = 133 !!!!!!

    Which software to trust????

    Wire dia = 3mm
    Gap between stub wires =6 mm (center-to-center distance between stub wires = 1.5 mm + 6 mm + 1.5 mm = 9 mm)
    Optimum cable tap position = 45 mm from open end (or 69 mm -45 mm = 24 mm from shorted end)


    [ATTACH=CONFIG]4509[/ATTACH]. [ATTACH=CONFIG]4510[/ATTACH] . [ATTACH=CONFIG]4511[/ATTACH]

    I used 3.5mm diameter copper wire with 6mm spacing, built the Franklin antenna according to your size, and tested it with a 50ohm feeder. The resonance point is 1080MHz, and the SWR is as high as 3 at 1090.

    Can you tell me where there might be a problem?

    Leave a comment:


  • abcd567
    replied
    Originally posted by raptor22 View Post

    Do I need a filter?
    Here is my data capture record
    Screenshot 2021-09-17 195508.png
    Yes you do need a filter. Heavy mobile phone signal present in GSM850 band.

    Optional: You may conduct this scan also. It covers full band of DVB-T (24 Mhz to 1800 Mhz)

    ​​​​​​In thread "Do I Need a Filter":
    OPTION-4:
    DVB-T plugged into Windows Computer - Using GUI Spektrum.exe
    Last edited by abcd567; 2021-09-18, 01:13.

    Leave a comment:


  • raptor22
    replied
    Originally posted by Oblivian View Post
    Did you cut the top of the antenna down and put it on a can?

    I can't make that decision from this side of the world. All those commercial ones are far too expensive in our local value.
    But a DIY from wire to test may be a cheaper investment to try. Many use home-made and have good range.
    Do I need a filter?
    Here is my data capture record
    Screenshot 2021-09-17 195508.png

    Leave a comment:


  • abcd567
    replied
    raptor22:

    Please brows these two threads
    :


    3 EASY ANTENNAS FOR BEGINNERS



    QUICK SPIDER - No Soldering, No Connector



    .

    Leave a comment:


  • Oblivian
    replied
    Did you cut the top of the antenna down and put it on a can?

    I can't make that decision from this side of the world. All those commercial ones are far too expensive in our local value.
    But a DIY from wire to test may be a cheaper investment to try. Many use home-made and have good range.

    Leave a comment:


  • raptor22
    replied
    Originally posted by Oblivian View Post
    Known as MMCX or mini-sma

    The antenna looks like it might be normal or RP-SMA (reverse pin)

    It would need a MMCX-SMA short length. Or some good coax and use a MMCX 'pigtail' between. Just remember each connector adds a little loss.
    Should I buy this antenna or DIY a new one myself?
    this is my theoretical range but I get only 32NM using the antenna which came with the dongle.
    WhatsApp Image 2021-09-16 at 11.56.11 AM.jpeg

    Leave a comment:

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