Questions tagged [circular-polarization]

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Turnstile antennas with a "single-point feed": what's the antenna theory behind this, and how do I build/model it?

The conventional turnstile antenna uses a 1/4wl phasing line between the crossed elements, to get the required phase shift. 4nec2 includes an example file, though, of a circularly-polarized Yagi using ...
1200bps's user avatar
  • 31
0 votes
1 answer
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I have a 433MHz LoRa Dipole antenna mounted on a rocket. I am looking for a suitable Antenna to receive data from this. Any Suggestions?

The idea was to send GPS data from the rocket to the ground station at 433 MHz using a Lo Ra transmitter - mainly to help locate it once it lands and also to provide in-flight telemetry. I have a ...
David Allan's user avatar
1 vote
1 answer
110 views

The HPBW of a helical antenna

can someone tell me what are the formulas of HPBW for a helical antenna? I've searched a lot and I saw that there are two different formulas of HPBW for the helical antenna, this one, $$ \mathbf{(HPBW)...
Abdullah Ali's user avatar
3 votes
2 answers
2k views

Can left-hand and right-hand circular polarizations exist at the same time?

I read in a comment: it doesn't matter which circular polarization you choose, because they are both present, and the whole point here is to select one of them instead of receiving both and getting ...
Phil Frost - W8II's user avatar
2 votes
1 answer
960 views

How to use 70 cm WiMo phasing harness for a COTS crossed yagi antenna?

In order to generate circular polarization in a crossed-yagi, a 90° phase delay is required between the horizontal and the vertical antenna. In practice, this is achieved either by making a mechanical ...
Ibtissam Latachi's user avatar
5 votes
2 answers
1k views

Does a parabolic reflector dish change circular polarity?

I've been receiving satellite signals in the L-band (~1.7GHz), recently. These signals are RHCP. So far, I've been using a DIY helical antenna in axial mode, and a patch antenna with cropped or ...
polemon's user avatar
  • 257
2 votes
1 answer
123 views

Why is it claimed that circular polarized RF has better penetration properties compared to linear polarized RF?

It is claimed in blogs and other unverified internet sources that circular polarized RF signals are better for penetrating structures, such as walls. An example here, there are many others when you ...
Edwin van Mierlo's user avatar
1 vote
3 answers
455 views

Would the antenna described work?

For reception of amateur radio satellites, turnstile antennas (consisting of two crossed dipoles fed out-of-phase) are often used. I've recently had an idea - what if two half-wavelength dipoles are ...
Mark's user avatar
  • 131
1 vote
1 answer
1k views

VHF / UHF - Terrestrial Circular Polarized Antenna

I've been doing mostly HF for the last 20 years and just recently installed a 2m/70cm mobile rig in my shack for base station work. I like to work FM simplex and repeaters when the HF bands are not ...
Inisheer's user avatar
  • 135
6 votes
1 answer
371 views

How to stack circular polarised antennas

I'm interested in stacking a pair of circularly polarized "crosshair" antennas. Do I construct such as both antennas are in phase with one another then match the two signals in phase via the coax line,...
Ben's user avatar
  • 347
3 votes
2 answers
1k views

What is Circular Polarization?

So I just learned that a satellite does not send out a circularly polarized signal, it just switches orientation slowly when it topples through space. I thought that because they were spinning, the ...
Skyler 440's user avatar
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9 votes
2 answers
3k views

Are satellites Left or Right hand circularly polarized?

I'm thinking of building some helical antennas for satellite work. I want to know which way to wind them. If satellites are spinning randomly, how can we know if they are left hand or right hand ...
Skyler 440's user avatar
  • 7,590
1 vote
2 answers
176 views

Will swapping receiver polarity on a spiral antenna change right hand to left hand polarization?

I'm evaluating a helix antenna, and wanted to try out a reverse circular polarization than it's designed for. I do know that it's balanced and has no other components that would preclude polarity ...
Adam Davis's user avatar
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