This one is really nice and compact, has good bandwdith (over 1MHz 1.1:1) and yet has maintained an excellent pattern at the same time with more than 10dBi.
PLEASE NOTE:
- This antenna WILL NOT show the true SWR in any antenna modelling package unless you are using one which uses the latest NEC4 calculation engine. Do not confuse your version of EZNEC with nec version. EZNEC uses nec2 by default.
- There are two sets of measurements listed below. One uses imperial sizes, the other uses metirc sizes. Ensure you use the correct one for the material you have
- 'within one or two millimetres' Will not do! take the time to ensure you get the spacing ant element lengths as close as you possibly can to the measurements below to ensure good, solid performance
- Please read the 'how to make the LFA Loop' page here
2 x 9 element versions of this antenna at the RSGB VHF Field day 2009
Note: performance figures centred on 144.300MHz the centre SSB frequency
Performance
Forward Gain: 10.06dBi at 144.300MHz
Front to Back Ratio: 20.06dBi at 144.300MHz
Bandwidth: 1MHZ below 1.1:1
Please read the 'how to make the LFA Loop' page here
Azimuth Plot of this wideband 4el 144MHz LFA
Elevation Plot
SWR Plot from 144MHz to 145MHz
Antenna Layout
Build Dimensions for UK/USA/European version Version
Element Spacing in metres Half element Length in metres Element Notes
Reflector 0 .5155 3/8 Inch - .514510mm Tube
DE1 .136 .426 Either 1/2 inch or 12mm Tube same size for both
DE2 .324 .426 Either 1/2 inch or 12mm Tube same size for both
D1 .657 .4625 3/8 inch - .4615 10mm Tube
D2 1.224 .4365 3/8 inch - .4355 10mm Tube
Notes:
DE1 and DE2 are joined at the ends by either 10mm or 3/8inch tube. Feed point is the centre of DE1
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