Tuning FX Radar

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bd2021

bd2021

Member
Nov 18, 2021
379
16
MN, United States
So the FX radar app doesn't seem to be displaying the true velocity, or is computing the energy incorrectly. For a pitbull modified benjamin bulldog with 135 grain slugs:

Shot count: First 5
Low: 907 fps
Hi: 939 fps
Avg: 923 fps
STD Dev: 10.8
Spread: 32.0 fps
3/23/22 12:35:47 PM, 939 fps 264.7 (264.3 calculated) ft. lbs
3/23/22 12:36:10 PM, 921 fps 254.3 (254.2 calculated) ft. lbs
3/23/22 12:36:35 PM, 930 fps 259.5 (259.2 calculated) ft. lbs
3/23/22 12:37:02 PM, 919 fps 253.0 (253.1 calculated) ft. lbs
3/23/22 12:37:38 PM, 907 fps 246.7 (246.6 calculated) ft. lbs



It is probably a rounding error, but on the other hand, I notice that my fx crown MKII strangely only shots in particular fps bins, e.g.,

905 fps

902 fps

(never 903 or 904 fps)



Anybody else notice this?




 
Probably the fps are with a decimal but that is not shown. So the calculation is ok.

Never seen if some numbers don't show up. Maybe it is just by accident.



Screenshot_20220321-171232.1648072127.jpg

 
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Probably the fps are with a decimal but that is not shown. So the calculation is ok.

Never seen if some numbers don't show up. Maybe it is just by accident.



Screenshot_20220321-171232.1648072127.jpg
Click to expand...

See if you ever get a 922 or 920. I get the same sort of results. Many duplicates but I think it is unlikely that the fps would be sorted into fps bins with interverining fsp bins being 0.

I only have about 60 or so shots with the 25 cal, and I have many 907, 905, 902 fps, but no 906, 904, or 903 fps. Seems odd.
 
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I agree hanging it is not the best way to do it. There are pros and cons. 

Con: It will effect harmonics. 

Pro: Hanging on the barrel assures it will always be pointed in the same direction as your barrel,, If you have it underneath and you change targets you may no longer be shooting directly over the chrono

Also when I got mine it no longer comes with the piece that attaches to a tripod. It used to come with an extra piece, so now you are kind of forced to hang it from the barrel.


 
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Interesting. 

I'm find that my FX radar sometimes won't "see" the pellet while shooting. I've tried adjusting the gain to 10% , but still misses shots. I'm sure a pellet flew as I heard the impact. Any suggestions? 

Thanks , Mike
Click to expand...

I've had quite a bit of this with mine, even down at 10% return level. Hoping that a clean and solid 5 volt supply will fix mine, if not it will probably be sold for a lab radar or something similar.
 
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I have an old Chrony shadow type velocity checker that works fine for a backup. I've used with my other airguns and archery gear for years. Runs on a 9 volt battery. Once in a blue moon it fails to register a shot . 

FX has a good idea but need to work out the bugs. Hopefully, it's a software solution. 

I do like the ease of the use FX radar , when it works properly. 
 
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I usually have to play around with the settings and its distance from the muzzle whenever I’m moving it between rifles. I have it powered with a small 5V USB battery pack and that has eliminated the burden of swapping batteries so often but I can’t say that has made it any less persnickety about getting reliable readings. What I like about it is the audible report via the smartphone and the ability to save a record of the string. However I cannot count on always getting the first shot and that is a massive negative for me because I need to know if regulator creep or stiction or anything of that nature is affecting the velocity after the gun has been idle.

What does work 100% of the time is a $30 Chinese chronograph. That makes me wish FX had skipped the fancy radar and just used a simple and reliable infrared illuminator/pickup. I guess they needed a Rube Goldberg feature to hit the $200 bracket.
 
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Another tip....

On an Android: When using the FX chrony, and you close it out using the 'back' arrow, then reopen and it doesn't 'see' the pellet and won't give a FPS like it just did when open. Use the three vertical hashes at the bottom left of your home screen and open that to see all of the apps that are open behind the scenes. That'll show all apps that have been used. FX should be one of those apps. Swipe it up and off the screen, that will actually 'close' it. Then reopen directly from the app icon again and it will start working as it should. I could not understand why mine wouldn't see the pellets until I figured this out. Works every time.

mike
 
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Thinking back to when I was testing my battery mod, no there is no microphone on this. I know this because I was able to wave my hand fast enough to get it to register (lowest speed setting), and my hand makes no noise. It can also track things like Nerf darts (if I remember correctly). Once you go into measurement mode, it turns the radio on and uses pure doppler to decide if something moved.



Also something that might be useful down range, it will measure an object approaching. Not sure if you can get the full 1100fps pointing this way, but maybe. Eventually I'll try it. This might be a cheaper option to get muzzle and downrange speeds to predict the BC of a round (maybe). Again untested and you'd want two of them which approaches the cost of a Labradar.
 
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