The Survival Podcast Forum

Survivalism & Self Sufficiency Topics => The HAM Radio Board => Amateur Radio How-To's => Topic started by: Carl on March 06, 2017, 07:46:32 AM

Title: The DIPOLE , the easy to make antenna for Ham radio
Post by: Carl on March 06, 2017, 07:46:32 AM
  So,you are new to Ham radio and need an antenna for the new to you HF rig. There are many choices though few that come close to the simplicity of the DIPOLE or INVERTED "V" antenna. While I enjoy the use of multi-Band antennas myself,many people just desire a simple ,one band antenna and these are easy to make from commercially made or home brew kits. A dipole is the most simple of antennas the can work on ONE HF BAND without the need for a tuner to tune the antenna,though an SWR METER should be used to verify the antenna is cut to proper length and matches the impedance of the radio so as to be safe when transmitting .

  A dipole or INVERTED "V" are the same antenna,just a slight difference in orientation. The dipole is center fed and stretched between two supports in a straight line,vertical or horizontal ,or even sloping ,though then it's not a dipole,or close to it,and normally has an impedance of 72 OHMS and so will indicate a 1.4 to 1.5 SWR...if your meter is doing it's job. The dipole is slightly directional to it's 'sides' and nulls a bit on the ends,so  should best be broadside to your intended 'targets'

  An INVERTED "V" is a dipole  with the center (feed point) held higher than the ends and is nearer to 50 OHMS impedance that your radio demands ad also exhibits an OMNI-DIRECTIONAL pattern . The Inverted "V" matches the radio better and is nearly equal ability in all directions. A good support on the feed point and the inverted "V" is happy to have it's ends tied to trees or fences ,lower to the ground,at the ends.

  So with a simple pair of wires with insulators you can have a somewhat directional,an OMNIDIRECTIONAL,or even a VERTICAL antenna ...each with advantages for different situations as a VERTICAL tends to have a lower angle radiation for long distance and the directional or omnidirectional dipole/inverted"V" and also ...when the dipole or inverted "V" are below 1/4 wavelength above the ground on the 40-60-80 meter bands you can utilyze NVIS ,or high angle of radiation to make use of HF in nearer proximity to your station (50 to 600 Miles) and actually operate into valleys,over mountains etc into areas where radio signals normally would not work.

3.75 MHZ      62.4 feet per side  124.8 feet total length
7.15 MHZ      32.7 feet per side  65.4 feet total length
10.12 MHZ    23.1 feet per side  46.2 feet total length
14.175 MHZ  16.5 feet per side   33 feet total length
18.1 MHZ      12.9 feet per side   25.8 feet total length
21.22 MHZ    11  feet per side     22 feet total length
24.9 MHZ       9.4 feet per side    18.8 feet total length
29.0 MHZ       8  feet per side      16 feet total length

Measurements are for finished length ,so allow extra wire for connections and adjustment for SWR at different locations.

  There are lots of options and plenty to read and deside on for your first,next,or last antenna.

Title: Re: The DIPOLE , the easy to make antenna for Ham radio
Post by: Smurf Hunter on March 06, 2017, 08:01:26 AM
Good summary info in one place.

Title: Re: The DIPOLE , the easy to make antenna for Ham radio
Post by: Carl on March 06, 2017, 08:02:16 AM
Good summary info in one place.


Thanks,you read faster than I type.