I am trying to receive SSTV Images from the ISS (145.8Mhz) and I all have is a simple "bunny ears" dipole antenna. In what configuration (straight, vee shaped, upside down vee, ...) and orientation should I place the antenna to optimize signal reception? Could you please explain why and/or link to some sources where I can learn how to find the proper orientation myself?
I've tried answering this question myself but I all found was tutorials that either didn't specify the antenna configuration/orientation or even contradict each other.
While vertically dipoles are widely discussed, there are not many sources (that I could find) that discuss other dipole configurations. Since the radiation pattern of a vertical dipole is shaped like a doughnut (where the dipole is passing through the doughnut hole), I was expecting that rotating the dipole by 90 degrees (so that it lies in the horizontal plane) would also rotate the radiation pattern accordingly. Apparently I was wrong.
Assuming that the information on that website is correct, I can't really find an orientation for good reception of a signal coming almost-vertically from the sky.
Also, I wasn't able to figure out what polarization is being used by the ISS SSTV transmission. This website reports it as "U: linear, V: linear", but there is no explanation of what U and V mean in this context (I assume it's a standard notion but I haven't been able to find an explanation either).
What does this polarization refer to anyway? Since the ISS rotates I assume the polarization will also shift by 90 degrees (twice) from the perspective of the receiver. At what point in the orbit does the apparent polarization match the nominal one?
Finally, to optimize reception I assume I'd need to rotate the antenna along with the ISS pass (to properly direct the radiation pattern and match polarization). What's the correct orientation at any given point in the orbit?
If reorienting the antenna is not possible, are there any tips for choosing a fixed antenna position? Is it better to optimize for reception when the station is directly overhead, for when it's rising/setting, somewhere in-between, ...?
As you can see I'm a little confused, and I would be grateful for any guidance from anyone more expert than me.