it seems not all SPI receivers are created equal. while i positioned myself for the best reception, i am still getting bouts of 30 something RSSI at only 40-50 meters away open road unobstructed. oddly though these are just momentary spikes where it rises to 50 something hence may be why i am not getting failsafe issues. watching your video at the park you seem to get consistently good signal strength all throughout.

SPI RX's are a hit and a miss especially since most of them are running reverse engineered protocols and it comes down to the quality of the boards.

Can you ensure the length of the antenna is approximately 31mm?

(06-Dec-2021, 02:36 AM)kafie1980 Wrote: SPI RX's are a hit and a miss especially since most of them are running reverse engineered protocols and it comes down to the quality of the boards.

Can you ensure the length of the antenna is approximately 31mm?

if you are referring to the white inner element exposed tip then yes it is around that length. does it have to be a hard number?? i actually undid the heat shrink to expose this white element.

Based on Oscar's post the optimal length is around 31.23mm: https://oscarliang.com/repair-2-4ghz-antenna-rx/

There are variations in antenna lengths by manufacturers due to specific tuning requirements to account for specific receivers hardware.

(06-Dec-2021, 06:18 AM)kafie1980 Wrote: Based on Oscar's post the optimal length is around 31.23mm: https://oscarliang.com/repair-2-4ghz-antenna-rx/

There are variations in antenna lengths by manufacturers due to specific tuning requirements to account for specific receivers hardware.

mine is exactly 25mm only! yeah i did learn way back these lengths wer indeed measured following an exact science. based on what oscar recommended it seems i have to strip off at least 6mm of the black outer sheath for optimal performance. hmm, shouldn’t happymodel be fully aware of this? or do they deliberately give customers a hard time??

I just measured the antenna on my Mobula 6 which is just a just a black wire (not a coax cable with a u.fl connector like on the new Diamond AIO boards) and the length of the wire is about 30 mm not including the soldered portion at the base which is about 1.5 to 2 mm.

You should have enough wire length to modify the antenna wire on the Moblite board which basically just means stripping away some of the ground shielding to expose the active element. If the range is worse than before then you can modify the wire back to the factory length for the exposed active element.

I guess Happy Model just bought a bunch of these premade U.FL coax cables and just put them on the board without altering the length of the active element. Just guessing unless someone has an explanation why Happy Model will do that intentionally.

your solid black wire on the mobula6 meets the 31mm closely as oscar mentions an acceptable +/- variance. i think its the same with the larva X which oddly is cramped between the chassis and battery hence the range issues.

the total length of my antenna from UFL plug to the stripped end is very generous at around 100mm++. i guess if i were to make a mistake during the stripping prcoess then i have enough antenna stock to work with! stripping to correct length should be an easy task. i just do not have the deft touch of a teenager with my middle-aged geriatric trembling fingers which were put to the test when i had to solder a motor wire that came off the moblite7. fortunately nothing burned but its not a solder joint worthy of praise!

so far i had been flying the mob7 indoors into adjacent rooms with the worst obstructions. i am getting as low as 20 something RSSI dips which does not trigger failsafe. previously i even had it go upstairs into another room and still no failsafe. this time its the VTX which had cut outs.

RF penetration though walls is hard to predict. Depending on what the walls are made of and what kind of interference exists in the premises, this can be tough to quantify.

Most people that fly at home experiment with different locations around the house such as a living room, or dining table or kitchen etc and different antenna combinations to get the best reception.

My Mobula6 just has a 25mW vtx power and I can barely fly around my house which is a brick construction with lost of residential wifi noise and I have a cell tower about 150m away.

Out of curiosity, did you double check your VTX tables to ensure you have the correct tables? What has recently been mentioned is that Betaflight 4.x onwards reverts to the lowest transmission power on the VTX if the table is not properly defined.

hmm, i just downloaded what looks like the vtx table for AIO boards which is only one table and no other from the various options. i will double check again. but so far i have no complaints using R-8 anywhere.

(06-Dec-2021, 09:49 AM)kafie1980 Wrote: RF penetration though walls is hard to predict. Depending on what the walls are made of and what kind of interference exists in the premises, this can be tough to quantify.

Most people that fly at home experiment with different locations around the house such as a living room, or dining table or kitchen etc and different antenna combinations to get the best reception.

My Mobula6 just has a 25mW vtx power and I can barely fly around my house which is a brick construction with lost of residential wifi noise and I have a cell tower about 150m away.

Out of curiosity, did you double check your VTX tables to ensure you have the correct tables? What has recently been mentioned is that Betaflight 4.x onwards reverts to the lowest transmission power on the VTX if the table is not properly defined.

as for the issue of vtx reverting to the low setting i think mine is good as it saves whatever vtx setting i choose. usually low setting at 25mW is acceptable already. btw i sent you a couple of vids via email. notice the RSSI values changing like a roller coaster. the open lot flight is like no more than 40 meters at best farthest from me.

newbie flight report:

today i flew a couple of packs outdoors in my favorite vacant lot nearby where i also almost lost my moblite7 fifteen days ago in my futile first attempt at fpv! this time it is easier to fly air mode since the quad is in a stable state of movement away from obstructions. i tried high speed runs and steep banked turns. the mob7 did not disappoint at all despite the diminutive size. while flying i thought to myself i will not crash this thing or anything with this type of flying unless i smack into something out in the open or develop some kind of equipment failure. i also thought to myself this kind of flying also gives me the doors wide open to doing the fun stuff and this is when things will become interesting as i may be slamming into things outdoors very soon!

fpv is indeed very rewarding and fulfilling as a part of RC flying. there is a unique thrill having that “you are in the seat” feeling of steering and maneuvering the quad. my early mornings are now spent on the front yard flying a circuit trying to do my personal best lap time in this imaginary course. the neighbors are now curious about the middle aged man with a box strapped on his face standing still with a little speck buzzing around. the mob7 is so quiet most of the people walking by do not even know its passing overhead if it do it high enough. cheers!

I was unable to view your videos as they have been marked "Private".

Yes, once you get the hang of it, you really like it.

I only get to fly weekends only because I need atleast an hour or so. Add to that it takes a while trying to get to my various flying spots to find which one is available and the un-packing and packing of gear.

I did try flying during weekdays while working from home but something always pop-up and then I feel bad about fully charged lipos sitting in a lipo bag.

I can fly my Mobula 6 or 1S BabyTooth in my fairly large back yard (shared with others) but I love flying my 5" the most and I need a good spot for that.

(07-Dec-2021, 06:01 AM)kafie1980 Wrote: I was unable to view your videos as they have been marked "Private".

Yes, once you get the hang of it, you really like it.

I only get to fly weekends only because I need atleast an hour or so. Add to that it takes a while trying to get to my various flying spots to find which one is available and the un-packing and packing of gear.

I did try flying during weekdays while working from home but something always pop-up and then I feel bad about fully charged lipos sitting in a lipo bag.

I can fly my Mobula 6 or 1S BabyTooth in my fairly large back yard (shared with others) but I love flying my 5" the most and I need a good spot for that.

oh so sorry about the videos! i am also a YT newbie. i shall check and revise settings. its not really the most spectacular cinematic experience but from someone barely a month into the hobby it was a blast flying outdoors without smashing into anything! funny thing about a quad is unlike high performance rc airplanes which i flew before these things have a ridiculous flight envelope making any control input imaginable possible to execute! in my earlier vids in the field i attempted hard steep banks almost entering into pirouette like a top which when sustained can almost induce spatial disorientation! funny looking at an almost vertical horizon bar, almost foregetting which way you banked due to the steepness of the turn. it is simply fun despite the tiny package.

today my optical lens for the EV800DM just arrived! it makes a world of difference as now i do not have to wear my reading glasses along with the goggles. much less eye strain but when i tried donning the reading glasses it still gave an additional level of clarity and detail! ergo i may do well with a higher grade spec lens! i was badly mistaken for downplaying the video quality of the system but it is actually very acceptable once corrected with the proper lenses. if this were the case with the better binocular goggles like the skyzone 04L with -6 to +6 diopters and better screens then those may be looming on the horizon for me!

funny i have spent more on getting the perfect image to compensate for my eyesight while the transmitter and whoop cost only a third of my fpv hobby!

You will get used to orienting yourself with regards to the surroundings. Keeping track of the horizon will become second nature.

Spending money on a good pair of goggles and transmitter is not a bad investment as it will last you a while and there is very little chance of damaging them.

Quads on the other hand, you can crash or lose.