this is a little off topic, but I need some information and can’t find it on google… I’m looking at using thisantenna, but it’s a waveguide style antenna, and while I understand the general idea of how a wave guide antenna works to create transmit gain, I do not know if it actually creates any receive gain. I cannot find any information about this. does anyone have any experience with waveguide antennas?
Indeed I do.
Gain is expressed in that article as 9dB, this is 9dB for both receive and transmit.
I have used waveguides before (180 degree) and found them to work quite well. Although be aware that often when you have a vertical waveguide the transmission polarisation is horizontal (this is also noted in that article.)
Cheers
Good evening Forepoint -
This particular waveguide antenna has horizontal slots cut through the broadside surfaces of the waveguide.
Let’s say it’s 1 slot on one side, for right now. The energy traveling down the waveguide from the transmitter sets up a current that flows along the sides of the slot cut through the conductive wall. The electrical field is oriented along the slot and so the electrical field of the energy that gets radiated from that horizontal slot will be horizontal.
That’s one slot.
Now, if I cut an identical second slot an electrical 1/2 wavelength further along the waveguide on the same side, that slot will do the same thing. The fields of both slots will reinforce in the direction normal (at 90 deg; in the case of this antenna mounted pointing straight up, the horizon) to the surface into which the slots were cut, but at angles above and below the horizon will sometimes cancel and othertimes reinforce. making the majority of the energy focused toward the horizon.
Two slots can double (3dB) the gain over a single slot, four slots give you 6dB, 8 slots give you 9dB, etc. I am guessing that this one has 4 or more slots on each side.
Since they claim this antenna is omnidirectional in azimuth, that means that there are identical sets of slots cut on both broadside surfaces, and there must be a little magic done to ensure that you get good radiation off the sides of the antenna (the small dimension of the waveguide).
A waveguide antenna can be very sturdy, takes ice and snow better than a yagi.
Since this is horizontally polarized, remember that with your client units.
Jon
I have not used this particular wave guide, but have had very good results from every wave guide aerial I have used - much better than most of the vertically polarised aerials claiming the same gain…