2013 m. rugpjūčio 12 d.

Compact and effective 2m/70cm dual band antenna for satellite operation



Antenna was designed for SO-50 satellite operation.
It has gains 4 dBd on 2m and 6.5 dBd on 70cm bands  and it is fed via single 50 Ohm cable (use as short as possible for comfortable operation)

All elements made from aluminium welding 3.2 mm rod. 
4 mm material can be used with no problem.
For other diameters and frequencies I recommend to use wonderful MMANA-GAL software.

Here's the antenna definition for MMANA-GAL basic.
Copy and paste the text between //////
(Menu > Edit >  Antenna Definition window)


/////// mark text below //////////

*
436.0
***Wires***
9
0.0,    -0.3495,    0.0,    0.0,    0.3495,    0.0,    0.0016,    -1
0.281,    -0.3495,    0.0,    0.281,    0.3495,    0.0,    0.0016,    -1
0.0,    0.3495,    0.0,    0.1506,    0.3495,    0.0,    0.0016,    -1
0.0,    -0.3495,    0.0,    0.1506,    -0.3495,    0.0,    0.0016,    -1
0.1651,    -0.3495,    0.0,    0.281,    -0.3495,    0.0,    0.0016,    -1
0.1651,    0.3495,    0.0,    0.281,    0.3495,    0.0,    0.0016,    -1
0.1405,    0.16285,    0.0,    0.1405,    -0.16285,    0.0,    0.0016,    -1
0.302,    0.1622,    0.0,    0.302,    -0.1622,    0.0,    0.0016,    -1
0.477,    0.1476,    0.0,    0.477,    -0.1476,    0.0,    0.0016,    -1
***Source***
1,    0
w2c,    0.0,    1.0
***Load***
0,    1
***Segmentation***
800,    80,    2.0,    2
***G/H/M/R/AzEl/X***
0,    2.0,    3,    50.0,    120,    60,    0.0

/////// end mark above this line //////////////////


Antenna is optimised for satellite operation therefore calculations must be done in upper band sides (145.85 MHz  and 436 MHz respectively)

73! de LY2SS

12 komentarų:

  1. The signal is sounding great. S9 in the maximum but some fading from time to time, like everyone.

    Hoping to see you on the satellite again very soon!

    Tim, G4VXE

    AtsakytiPanaikinti
  2. Thank you Tim for the nice report!
    You were loud here too! And then that sudden fading... See you on the next pass!

    73!

    AtsakytiPanaikinti
  3. 73.51 TNX QSL QTC very good Pls QSY PDF Email TKS from San Cristóbal Tachira Venezuela

    AtsakytiPanaikinti
  4. Hello everybody! I want to make 2+70 moxon antenna with moxon on 144 and 3 el Yagi for 435
    Can you recalculate it for 6.5 aluminium wire.
    Thanks a lot by UB8JAS

    AtsakytiPanaikinti
  5. What kind of wattage could this antenna handle?

    AtsakytiPanaikinti
  6. I think it depends on what type of cable being used and what are isolating parts mande from (dipole feeding point and isolators between Moxon vibrator and reflector). I used RG-58 cable. My guess it should handle 50 Watt on VHF/UHF. But since I own only Baofeng radio I could not test it.

    AtsakytiPanaikinti
  7. Great antenna , i made it with 20 mm Conduit boom and the Coax is 75 Ohm. its Work Good.
    de YC1TDL

    AtsakytiPanaikinti
  8. This looks really nice. What did you use to connect the elements to the pipe?

    AtsakytiPanaikinti
    Atsakymai
    1. This is the hardest part, because there's no way to reliably solder aluminum elements with copper coax wire. I used inside part taken from https://ksd-images.lt/display/products/0000/3645/12351460.jpg
      It consists of small solderable mettalic tube with two nuts. I cut that tube in two parts and molded (after soldering cable) them in plastic element holder. Then element is fastened with nut. I hope you got the idea. 5 years passed since I made that antenna but I still don't have the idea how to make that part properly. Everybody need compact, inexpensive, easy to make for beginners and reliable solution but I haven't seen it yet.

      Panaikinti
  9. Thanks. This is very useful. How about the clamps to connect the directors and the reflector to the pipe? The parts you used look perfect but I can't find them on the internet.

    AtsakytiPanaikinti
    Atsakymai
    1. These are clamps used attach PVC pipes to walls. Like that
      https://ksd-images.lt/display/products/0000/0898/10452161.jpg?h=2000&w=2000

      Panaikinti