I recently purchased a Kylin Fpv goggles from Chintal (Rcmumbai)
It took me a while to check them as i was quite busy in assignments.
But when i tried them there was a lot of fluctuation in the video even i was flying only within 100meter they get more worse when i go far. At the same time my other VRX works flawlessly.
I can't fly even my plane with it. So i thought there can be following reasons-
1. Auto tuning channel is not working properly
2. Rx antenna is faulty or it is wrong polarized i.e. we usually used right hand polarized but i believe it is left hand polarized.
3. Rx antenna connection is not good or loose.
4. Rx is faulty

Manually matched the channel
I checked by changing antenna but no improvement also stock antenna is SMA type but we use RP-SMA type.(ordered adaptor from Amazon)
Checked the connections of antenna inside the goggles it also looks fine(Ordered one pigtail from Amazon)
Don't know if Rx is faulty.

I'll install my DVR in goggles and post the footage.

Need some expert advice how can i give it a AV input so that i can add my other Video Rx to it? 

yes the stock antena is left hand polarized so try buying right hand one like fatsharks or any other u like
GOOD LUCK & HAPPY FLYING
$@! out