Frequency hopping experiments on the NRF24

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RichardT
Posts: 18
Joined: 03 Mar 2019, 17:15
Location: Surrey

Re: Frequency hopping experiments on the NRF24

Post by RichardT »

For anyone interested who hasn't seen this Youtube video on range testing of various Nrf24 modules and antennae here's a link - https://youtu.be/gtM832Z0ujE - iforce2d is the author and it's called - Ultimate nRF24L01 range test comparison. In another video he's done a successful 30km range test!

It has shielded vs. unshielded with different antennae. It's a bit long; at about 18:40 mins there's an essential bit which has pictures of the types of Nrf24 used.
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Phil_G
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Re: Frequency hopping experiments on the NRF24

Post by Phil_G »

Thanks Mike, good to know... and Rich, his comments after 18:40 ring true with some but not all of my own 'open' modules - I've found screening helps the funny ones, I have several times noticed hand-proximity effects, usually making the signal better but sometimes making it worse!
iforce2d at 19:20 in the video wrote:"...I was wondering about whether the whip antenna was interfering with the actual radio board itself, due to it not being shielded... ... this is what my transmitter that I keep complaining about is set up like... the signal from the antenna is quite strong and can interfere with the innards of [the NRF] since its not shielded..."
My Pixie and Pico both have a screen made from kitchen foil on card, and one of the car transmitters improved with a couple of copper-wire radials:


IMG_20200802_235616.jpg

IMG_20200802_235628.jpg

IMG_20200802_235731.jpg

IMG_20200802_235744.jpg


The 'new' screened NRF versions show none of these effects, dont appear to need extra capacitors, and seem impossible so far to upset, and believe me I've tried, I've thrown everything at them and they carry on regardless. For me theres no doubt now, this was indeed a Eureka moment!

I left a pair running on soak test overnight last night, with logging to pick up any failsafe or resyncs - no issue, 100% all night long and still running now - thats about 18 hours solid. Yesterday I was constantly cycling transmitters & receivers trying to provoke a hiccup but failed dismally - a solid 200 packets per second all day long. I wish I'd realised from the start that screened versions were readily available!

I've swapped out the 'open' modules in the Talisman, the RS Navigator, and the OS Pixie, and I'm going to do the model car transmitters next. I'm convinced the change is worthwhile. The OS Cougar still has an 'open' NRF set to 1mbps awaiting the range-test I never got around to - I will.

Heres the Pixie with its shiny new module, compare with the top pic above - kitchen foil consigned to the bin :D


IMG_20200924_171112.jpg


We need some weather now so I can take the Talisman slope-soaring again!

Cheers
Phil

Update:

So far I've refitted 4 of my NRF conversions with new 'screened module' - the OS Pixie, RS Navigator, Talisman and the bench-test tranny - and it occurred to me that maybe I should do a range-check before swapping any more - if they turned out to be no good I didnt want to have to swap them all back again :D

Today there was an opportunity to do a ground-range check, though not on my usual straight road, so we ran out of space at 500 metres at which distance it was still absolutely solid, 200 packets per second. I also tried the +PA+LNA version of the receiver (with the two pigtails) for the first time, which also behaved perfectly, frankly I couldnt tell any difference to the RF-Nano receivers - I really need a longer road! I'm perfectly happy to fly these trannies again now, knowing that the new screened RF modules share the terrific range of the old open ones.

The screened version is my 'NRF of choice' now, I wont be buying an more 'open' ones and the ones I have in stock will probably be used for receivers :D


IMG_20200705_225242_884.JPG


Cheers
Phil
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tiptipflyer
Posts: 393
Joined: 16 Feb 2018, 22:49
Location: Germany

Re: Frequency hopping experiments on the NRF24

Post by tiptipflyer »

Regarding the bad RF-nanos, I also had four of them. After complaining, Keywish did send me four new ones immediately, which are perfect. They even refrained from returning the old, bad ones.
So I am very pleased with the service, Keywish is offering.

Frank
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F2B
Posts: 200
Joined: 16 Feb 2018, 11:23
Location: 20 m NE of Amsterdam

Re: Frequency hopping experiments on the NRF24

Post by F2B »

I've had the same experience as Frank did, received them today.
Never have been treated this well after a mishap like this.
Which must have been a shock to the people at Keywish as well.
Working on some other projects now, but I'll report when trying these tiny marvels.
F2B or not to be....
bluejets
Posts: 316
Joined: 19 Jun 2019, 04:09

Re: Frequency hopping experiments on the NRF24

Post by bluejets »

Very difficult getting a straight answer sometimes when dealing with the Chinese.

At times I've outlined the problem quite logically and received an answer so far off base, I just have to say, WTF.

Normally I detest any of these acronyms as they almost drive me crazy sometimes but apparently it's not looked upon as being as offensive ( work that one out) and besides, there's not anything that come close to emphasising the current situation.

Roll on the Queen's English. :D
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Phil_G
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Re: Frequency hopping experiments on the NRF24

Post by Phil_G »

bluejets wrote: 12 Oct 2020, 10:11Roll on the Queen's English. :D
Its actually "English Language Day" today Jeff :D (the real one, not the fake UN English Language Day, which is actually St Georges Day)

Heres a list of my own RF-Nano manufacturing codes, that have been tested good for 250kbps.
So far my only bad ones have all been 1913CL.
Attached is the test program again.

Good:
1840YD
1447IF
1937BU


Bad:
1913CL
Attachments
isplus.ino
(917 Bytes) Downloaded 165 times
MaxZ
Posts: 330
Joined: 31 Jan 2019, 11:48
Location: Boskoop, Netherlands

Re: Frequency hopping experiments on the NRF24

Post by MaxZ »

Well, it is not a new project that I can show, but I have not been posting for a while. But just now I did a final check, and I am happy to report that I have successfully upgraded my diy transmitter with one of the modules Phil posted about a few weeks ago! (https://www.aliexpress.com/item/4000132850562.html)
My dear wife kindly assisted me by holding the transmitter, while it was on automatic sweep, on the street corner, and I could walk along the street for some 130 meters LOS before the Rx and servo started to splutter. Maybe not a perfect score, but I am happy to use it like that on a surface vehicle/boat.

I did have to change the internal layout though, because the new HF unit may be shorter than the old one, but it is a bit wider, and that was just too much to fit it between the stick unit and the top end of the box (together with the ProMini). So I had to mount it in the vertical with the antenna sticking out through the faceplate, but that is just fine, I can bend it in any direction anyway.

Cheers, Max
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tiptipflyer
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Joined: 16 Feb 2018, 22:49
Location: Germany

Re: Frequency hopping experiments on the NRF24

Post by tiptipflyer »

Hi guys,
regarding my Futaba FT5D replica transmitter posted here:
viewtopic.php?f=42&t=971&start=38
The Tx has quite a lot of flying time since I built it without any problem.
Now I replaced the tx module with the new shielded NRF24 version. Works great as expected and the instalation is more tidy as before.
FutabaFT5D7.JPG
Frank
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tiptipflyer
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Location: Germany

Re: Frequency hopping experiments on the NRF24

Post by tiptipflyer »

This is a simple S/C transmitter with only a few gimmics using the shielded NRF24 amd a promini.
It has full S/C compound incl. pick up elevator and three position sequential throttle plus inactivity buzzer, voltage alert and throttle led (not connected yet).
It is a very tiny block and will fit in an Engel Handy transmitter case in the original size with ease incl. a 2s lipo or a 9V block lipo.
My other Engel Handy replicas are all a little bigger to give enough space for either an Orange 2.4G module or a Jamara 35MHz module. They do not fit in the original size case. (75x35x35mm)
That brings back memories again, I had the real Handy Tx when I was 12 years old, stearing a Graupner Kitty with a Kinematic actuator.
SAM_4007.JPG
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Kitty002.jpg
Frank
Martin
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Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: Frequency hopping experiments on the NRF24

Post by Martin »

This may already have been reported here - if so, I'm sorry.

This guy on instructables claims to have significantly enhanced the range of the cheap nRF24L01+ modules (the unshielded ones with no PA) by a simple antenna hack to add a dipole antenna in place of the PCB one.

Image

https://www.instructables.com/Enhanced-NRF24L01/

I'm not suggesting we try it for the transmitter - the shielded module power amplifier and 'proper' antenna is recommended.

But might be worth some tests for a receiver? Also the idea might work for adding the 'whisker' type quarter-wave thin co-ax antenna often seen on commercial receivers? You could probably modify an RF-Nano the same way, as it has the same kind of PCB antenna? For inital cheap tests better to use the almost throwaway stand-alone nRF24L01+ modules, and finally perform a before-and-after modification test using the same RF-Nano with the same transmitter in the same location.
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