How efficient is a doublet antenna?
An efficient doublet should be at least 1/4λ to 1/3λ at the lowest operating frequency. A 3/8λ version has an efficiency greater than 98% relative to a λ/2 dipole and can have SWR values that are reasonably easy to match.
Is a doublet a good antenna?
Doublet antennas provide an ideal form of wideband wire antenna that is low cost and can be erected very easily. As such doublet antennas can provide an ideal solution to many HF antenna requirements.
How long is a G5RV JR antenna?
G5RV JUNIOR is a HF Wire Antenna, covering 40m to 10m bands. It’s overall length is 51ft 15.55 meters, Ladder line 15.6 feet 4.77 meters and should be fed with good quality 50 Ohms coaxial cable (recommended feed length of 45 or 90 ft).
Does a doublet need a balun?
Like all of the single-ended configurations, it required a balun on the output to allow for balanced lines. The standard version of the balun used a 4:1 impedance ratio either though a misunderstanding of the impedances likely to be present at the terminals or because such baluns were cheaper to make than 1:1 baluns.
How long is an 80 meter dipole antenna?
Each dipole leg is 34.4 feet long. Note that the SWR on 80 meters changes very little compared to Fig 2. No change was made to the 80-meter dipole or the transmission line. Fig 6 – Measured SWR for the 80- and 40-meter multiband antenna system.
What bands will an 80 meter dipole work on?
Read more about . . . . Dipole Length Calculations.
|Approximate Lengths for HF Ham Band Dipole Antennas|
|Band (MHz)||Length (Feet)||Length (metres)|
|3.5 (80 metres)||137||42.2|
|7.0 MHz (40 metres)||68.5||21.1|
|10.1 (30 metres)||47.5||14.7|
Will a G5RV Jr work on 80 meters?
The G5RV was designed as a 20m antenna with a little gain that matches to 75ohm coax and it just happens to work fine on 80 through 10m although 80m is down a bit. The G5RV JR is half size and would work best on 10m and is useable 40 through 10 or even 6m and 40m will suffer a bit.
How high should dipole be?
Recommendation. For best results, dipoles should be at least 1/2 wavelength above ground level. For the lower bands, especially 160-40 meters, this can become impractical–place your dipole as high as your situation allows.