I know I've mentioned this before, but here is a range of 433MHz antennas...
http://www.simplesolutions-uk.com/pr...433mhz-antenna
I know I've mentioned this before, but here is a range of 433MHz antennas...
http://www.simplesolutions-uk.com/pr...433mhz-antenna
I tried all those and use them for picking my nose now, useless!Originally Posted by Ian Davidson
Purveyor of the FPV secret sauce at ImmersionRC
Useless for picking your nose with, or as antennas?
If they're useless as antennas that is odd (although I'm not doubting you) as I know their 900MHz 'rubber duck' style antenna is the best of its type I've tried and is the one stocked by many FPV vendors.
http://www.simplesolutions-uk.com/pr...le-whip-916mhz
Seldom is the antenna a problem, but the implimentation usually is a big one. Dipoles at 433 MHz are large, so most people tend to fold them up or lay them flat which is the worst thing you can do. Thus a 1/4 wave whip usually does well as it can be left vertical eventhough its efficiency could be better. I need to see how a 1/2 wave whip performs (and if it will stand upright), but these allow for better implimentation on the aircraft if it has a tail.
The turnstile is really a good solution only when you need to lay your RX antenna flat. Being dual polarizaed and havnig no nulls, it has a predictable pattern. However, there will always be some loss due to the fact that you are polarizing in multiple axes.
-Alex
If it is broken, fix it. if it isn't broken, I'll soon fix that.
videoaerialsystems.com - Performance video piloting
Both, the majority of them are normal mode helicals which are fine for applications such as handheld radios for voice comms, but not efficient enough to make the most of a 433MHz RC control link.Useless for picking your nose with, or as antennas?
Purveyor of the FPV secret sauce at ImmersionRC
Sircana (maybe sassen), sorry for reviving this thread but I got to thinking and want to make sure I'm clear on the gain on the dipoles. Are they really 8db better than the monopole or is it just 8 counts on the exuhf rssi indicator (or does the rssi report db)? That seems like an awful lot of gain...or that the monopoles are pretty bad.
I'd test this myself but I don't trust my gear with the monopoles, it is just flakey for me.
In the ideal position (vertical against vertical), they showed around 7dB more signal, but they also have a wider null. Without testing them in an anechoic chamber (I haven't done it just because I cannot simulate the EzUHF ground plane without distroying it...) I cannot give you more details, but I would say this difference comes from a higher directivity from the dipole (a flat donut), and more efficiency.
But just considering Trappy's flights monopoles rock. In fact this test was not to discuss dipole vs monopole, but to find if the small normal mode helicals were good enough for "normal people" ranges.
The dipoles are less omni and hence offer a bit more gain, which is great for long range, or level flight, they do however have a much more pronounced null. They do indeed offer about 6 to 8 dB more gain when compared directly to the monopoles.
Purveyor of the FPV secret sauce at ImmersionRC
I'm not gonna run dipoles, I'm just curious. Seems to make sense for guys flying quads through trees and buildings.
There was a great video demonstration here of someone doing a test using a diversity RX and a monopole on one, dipole on the other while displaying rssi from each. You can very clearly see the much larger null of the dipole in that video...
It actually got me thinking about going back to a single monopole for the eurofighter... I have the EZUHF lite RX in that one, and it's currently got a sander style dipole but range will never be more than 1 km or at most 1.5 to 2km and of course flight will be aerobatic, hence why the null is perhaps more concerning than the lack of range from a single monopole.
Still haven't made a decision on that front yet!
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