Cheap broadband planar elliptical dipole antenna
Posted: Fri May 11, 2018 11:14 pm
Cheap broadband planar elliptical dipole antenna.
The antenna consists of two ovals (Goldern Ratio) disks
Inner of the coax goes to the top disk,
Braid of the coax goes to the bottom disk.
Each of the ovals dimentions are 335mm x 207mm
Short length of RG58 or LMR195 would be ok for connection to the disks.
With a female type connector of your choice to the lower end of the coax.
Keep the distance between the disks close together 1mm to 3mm.
Run the coax down the lower section of the disk,
Could use glue/silicon/gaffer tape here, To keep the coax firm against the lower disk.
Silicon a plastic cover over the connections to keep water out.
Each disk could be made from Aluminium or Galvanised tin sheet.
You can solder directly to tin, Though the aluminium will require
two small brass plates one bolted to each disk.
The two ground plane radials should be bolted to the lower disk (see pics)
So the lower disk should be of slightly thicker gauge material for strength.
I mounted the two disks on a recycled plastic garden stake.
Do try to mount them on some sort of plastic as there is more moisture in wood,
And could impact performance.
You can transmit on 146mhz and anywhere between 250mhz to 2800mhz with an SWR of around 1.5:1 throughout the range.
Will receive 118mhz to 2800mhz or greater.
This based on a dipole so it has increasing gain in frequency and as such is some what Bi-directional.
It is neat because you can go any where in the ranges stated and not have to change antennas.
Uses..... VHF, VHF-UHF-TV, UHF low, UHF high, ADSB, 23cm Band....e.t.c.
My 9 element UHF antenna will out perform this antenna, Though not by much.
Also the 9 ele has a restricted bandwidth.
My 5/8 over 5/8 vhf antenna will beat this also (really digs out distant signals)
Though once again only works in the VHF region.
For ADSB I use the Antenna to LNA4ALL to 900mhz highpass filter (Or Bandpass filter) to SDRplay.
Easy to build and pretty cheap and works pretty well.
Any questions do ask...cheers Tony.
The antenna consists of two ovals (Goldern Ratio) disks
Inner of the coax goes to the top disk,
Braid of the coax goes to the bottom disk.
Each of the ovals dimentions are 335mm x 207mm
Short length of RG58 or LMR195 would be ok for connection to the disks.
With a female type connector of your choice to the lower end of the coax.
Keep the distance between the disks close together 1mm to 3mm.
Run the coax down the lower section of the disk,
Could use glue/silicon/gaffer tape here, To keep the coax firm against the lower disk.
Silicon a plastic cover over the connections to keep water out.
Each disk could be made from Aluminium or Galvanised tin sheet.
You can solder directly to tin, Though the aluminium will require
two small brass plates one bolted to each disk.
The two ground plane radials should be bolted to the lower disk (see pics)
So the lower disk should be of slightly thicker gauge material for strength.
I mounted the two disks on a recycled plastic garden stake.
Do try to mount them on some sort of plastic as there is more moisture in wood,
And could impact performance.
You can transmit on 146mhz and anywhere between 250mhz to 2800mhz with an SWR of around 1.5:1 throughout the range.
Will receive 118mhz to 2800mhz or greater.
This based on a dipole so it has increasing gain in frequency and as such is some what Bi-directional.
It is neat because you can go any where in the ranges stated and not have to change antennas.
Uses..... VHF, VHF-UHF-TV, UHF low, UHF high, ADSB, 23cm Band....e.t.c.
My 9 element UHF antenna will out perform this antenna, Though not by much.
Also the 9 ele has a restricted bandwidth.
My 5/8 over 5/8 vhf antenna will beat this also (really digs out distant signals)
Though once again only works in the VHF region.
For ADSB I use the Antenna to LNA4ALL to 900mhz highpass filter (Or Bandpass filter) to SDRplay.
Easy to build and pretty cheap and works pretty well.
Any questions do ask...cheers Tony.