Easy Build - Short Effective Multi-band HF Vertical Antenna

Описание: Build Instructions - build this in 20 minutes!

Materials
1. Red banana plug
2. Black banana plug
3. BNC to banana plug adaptor
4. SOTABEAMS Tactical Top Insulator (Part no. TTOP-100)
5. Pre-constructed coax common mode choke
6. Pre-constructed 49:1 transformer (optional for the 40m band)
7. SOTABEAMS yellow lightweight wire (Part No. AWLW-100)
Also, various lengths of heatshrink tubing in red and black and blue. Soldering iron and solder.

Construction
1. For the vertical element, Cut 5.5 m (plus a little extra for folding at the top) of wire and solder (tin) one end. Place heatshrink over the wire. Screw onto the red plug. Warm the heatshrink. Loop the top end through the top insulator and secure with tape for testing and later heatshrink for a permanent solution..

2. For the counterpoise, cut two 4.25 m lengths of wire. Strip and tin one end of each wire. Place a thicker and two thinner lengths of heatshrink.

3. Solder the wires together and slide the heatshrink down. Connect to the black banana plug.

4. Slide the smaller heatshrink inside the larger piece and bend the counterpoise wires so that they are 180 degrees from each other. Then use a hot air gun to shrink the heatshrink. The counterpoise wires should cool and remain 180 degrees in opposition.


5. The counterpoise ends can be simply looped and heatshrink used to finish them. Alternatively, attach short loops of guy line and heatshrink on.

Testing
The antenna was modelled on EXNEC. Radiation pattern (40m) shown is good in the horizontal plane and gain is -4dBi at this frequency, which is not surprising given its short length.

SWR is around 10:1 for every band above 40m, which is within the range of most tuners. At 40m the SWR is 23:1, which is why I put in a 49:1 at this frequency.

Testing
The antenna was modelled on EXNEC. Radiation pattern (40m) shown is good in the horizontal plane and gain is -4dBi at this frequency, which is not surprising given its short length.

SWR is around 10:1 for every band above 40m, which is within the range of most tuners. At 40m the SWR is 23:1, which is why I put in a 49:1 at this frequency.



This effective multi-band antenna will work on 20m-10m with a tuner and with a little extra help, it will also work on 40m. I've already tested this antenna on a rocky mountain top:
   • Short HF Multi-band Antenna - 40m-10m!  

Here's my video explaining how random lengths work with a 9:1
   • Which Balun, UnUn or Choke to use and why?  

73, Fraser MM0EFI