Itelite DBS mods P3P troubleshoot

mcgrath111 · Aug 29, 2017

JohnnyB said:
Only reason I didn't mention the sunhan amps, though they help a little it's not as much as you would think because an amp that doesn't have automatic gain control, it's output power is totally based on the input it receives. Though is says 3 Watt, it's nowhere near because of the tiny bit of input it receives from the remote.
Here's a pic of an inspire remote with a 3 Watt sunhan attached, which has even more output from the remote than the P3, measuring straight out of the amp....
This is the power that's fed into the antenna...

Power that's fed into the antenna, plus your antenna gain = total power ERP. This is 16.28dBm and if I add the 9dBi DBS antenna that gives you 25.28dBm of total power ERP (Effective Radiated Power) This would be the same method DJI uses to get their specs.
25.28dBm converts to .33 Watts.

The difference between that and an amp that does have AGC (automatic gain control) is that one with AGC will take a small amount of input and will automatically adjust the gain to its max clean performance, without distorting the signal. Example.. this is a RF-Linx SAXU 1.5 W amp that does have AGC... Here are the results...

28.28dBm plus a 9dBi antenna = 37.28dBm total power.. also called ERP. (Effective Radiated Power) which converts to 5.34 Watts.

Though the sunhans would help, measurements says it's not much. But this is just one person's opinion (a blue collar guy at that) that has both kinds of amps and both kinds of antennas (DBS and Maxx).... Like myself, some has to find out on their own what works best for them. My findings however, these antennas performance didn't change as much as I had hoped by adding the amps.
In a good location, I can fly beyond VLOS almost in any direction with the 9dBi DBS, (without amps) without even pointing the antenna at the AC.
IMO, something (trees, wifi interference from the 100's of houses/business's that surrounds you) is the cause of your problems. But that's just me. (Not being sarcastic)

Great response, Im starting to get my head around all of this!

I took it out today and hit 1.6km on the beach (though houses behind so there would still be interference).

I think at this stage I dont need the maxx and Im happy plotting around the 1-2km mark.
With that being said, ill probably get twitchy hands and end up buying the maxx haha, but perhaps ill hold off on the amps for the time being.

Thanks for all your help much appreciated!

JohnnyB · Aug 29, 2017

Don't take me wrong.. sunhans have there place in my set-ups. It's nice to have various setups for different situations. The lobe on the 14dB Maxx is a lot narrower and tighter.. aiming would be more a lot more important, but as stated above.. it will penetrate... Nothing wrong with having an assortment. Will it penetrate where you're wanting to fly? Find out

JohnnyB · Aug 29, 2017

One more suggestion (hint)... the quality of everything in your signal chain matters, even if it's one set of cables between your antenna and controller. A good set of shielded cables can make a bit of difference. Unshielded cables can introduce interference into the signal... Research your components.

k9time · Aug 30, 2017

Johnny is correct on the amp thing. Its not as easy as just hanging amps on and getting incredible distance. Sometimes I get a mile , sometimes I get lucky and the stars, moon and wifi interference all line up and i get 5 miles. And then there's the can of worms you open when adding them.. Another battery or batteries to maintain, building your own shielded cables to get the right lengths for your setups and lugging all of it around. Next is a tripod setup and it goes on and on.. I love both my tricked out birds but it's been a long haul .. Luckily there is some great guys and info on this forum.. Digdat0, DirtyBum, Procharged97 , Matts175 and WilliamM have been great teachers and great reading when you search out their posts. Good Luck and great flying..