First, some background. This isn't required reading, so you can skip to the last sentence of the text block. 

So, I'd previously been "measuring" throw speed using video. It seems that at high fps (200 or more), this gives fairly accurate readings, but it's always a delayed result and quite tedious when analyzing a series of multiple throws.
After noticing that my readings approached 60 m/s using a stone, I had to rule out the sport radars I was originally targeting. For these devices, the speed data is close to the limit, and the projectile must fly toward the radar.
Next, I started looking at shooting chronographs based on Doppler technology. The FX chronographs caught my eye first. The first generation was a bit of a turnoff because it was battery-powered and hard to find, and the second generation supposedly had a minimum speed measurement of 90 m/s (according to the specifications on some websites; I haven't used it myself, so please correct me if anyone has!). So I continued looking and came across the Garmin Xero C1, which I purchased. Incidentally, there's a similar model, the Athlon Rangecraft Velocity PRO, which, judging by the reviews, slightly overstates its speed measurement figures.
I've been on a couple of testing trips so far, and I can't say I'm satisfied. The device works fine, but it's not designed for use with a sling, to put it mildly. Also, I never expected the readings to be displayed only on the radar, without real-time transmission to a phone app or voice alert. I noticed that it detects throws more reliably when I'm standing in front of it and the throw trajectory is roughly level with it. However, I was also able to detect throws when I stood about a meter behind it and threw slightly above the device. This allows you to see the display where you can track the throw detection and indicators, but the risk of damaging the radar is significantly higher. I'm considering installing a protective transparent plexiglass cover in front of it, for example, but that's not particularly practical in the field.

Therefore, it would be interesting to know who uses what kind of projectile velocity measuring devices besides video (if any) and can give advice on how best to place them, where to stand, how to safely throw relative to the device, and so on....

swiftcreek wrote on Jul 2^nd, 2026 at 2:49pm:

Yeah, in his video and in the Mersa video you can see something exactly like that. 
And yes, FX has an app that transmits real-time data to a smartphone/tablet (and also seems to provide voice-over), since they don’t have a built-in display.
And yes, the specifications for this device list the minimum measurement speed as lower than that of the second version. I wonder if the second version is capable of recording such low speeds.

It is assumed that different small Doppler-based devices have similar acquisition parameters for measurements, so the installation methods and "tricks" may work the same for all of them.

I have tried 4 different radars.
1. Pocket Radar Smart Coach
2. FX Pocket Chronograph Mk 1 (no longer manufactured)
3. FX Archery Chronograph   (no longer manufactured)
4. TAG One

#1 has great sensitivity for lots of objects, but only a speed range of 11 - 58 m/s
#2 was by far the most reliable and had a huge speed range (6 m/s - 300 m/s)
#3 had the same apparent specs as 2, but the sensitivity was terrible. It wouldn't pick up stones hardly ever.
#4 has a speed range of 11 - 100 m/s but the sensitivity is not great for small stones (ok for 80g and up).

The new FX Pocket Radar has too high of a speed floor, as mentioned.

Some pointers on using doppler radar devices.
1. All of these require the throw to be inline with the direction the device points (all of them except the #1 require a phone to use). 

2. The more inline the release of the projectile and the direction of travel with the antenna the better the return signal and more reliable the readout.   All of these have cosine error, so the more off angle, the lower the readout will be relative to the actual speed.

3. Things that reflect radio/microwaves will have higher return signals and hence be easier to pick up.  So, metallic things work better. Potentially, painting them with metallic paint could help (I have yet to try this, but have tried aluminum foil).

4. The internal algorithm to turn the range of speeds measured by the device into a single speed can affect the reliability. The TAG one often doesn't give a readout because the characteristics of the projectile sometimes don't match what is expected, so no readout is given (that is what their main engineer told me over email.) For example, I cannot get it to give a readout of a tennis ball thrown over about 70mph no matter what I do. I believe that the velocity decay is too fast and the algorithm doesn't have high confidence to fit the max velocity, which is why it won't give a readout (even with reflective material and a reflector on the radar, I couldn't get a reading).

5. You can use a reflector to increase return signal and potentially the frequency that you get a readout. See Floating Flint's excellent video.
https://youtu.be/U73vYYoL2PQ?si=ewp0XHVY_2HdVUxe
Surprisingly, this doesn't seem to help with the TAG One.

6. There is a distance around the centerline of the device that will be more reliable for giving a readout. It is different for every device depending on the internal antenna. Depending on the emission pattern of the antenna. For example the FX would give a readout if I was off to the side by several feet, the TAG one will only give a readout if I'm within about 6" of centerline. 

7. There is a finite distance away from the device that it can get sufficient return signal to give a reading. Too far away from the device and the transmitted radio signals from the device are too weak to reflect strongly back to the device.
So, that is why throwing over the top (along with tip 6) works well sometimes.

Archaic Arms had good success over the top of the radar. I didn't like doing it, because it always reduced the readout speed by 1-2 m/s (or more depending on drag of the ammo). This is because the readout seemed to start several feet in front of the device (ostensibly from the antenna pattern). I did do a vetting of the FX both with a tennis ball and a plastic glande and good ol' fashioned high-speed imaging. The radar and imaging were within 1 m/s of each other. And when Archaic Arms hit 82 m/s, this was over the top, with a lightweight stone, so the release velocity was likely a bit higher.

If you do stand behind it, a protective case, like what Primal Slinging did with his GoPro Case (https://youtu.be/dsLjZZcHN7I?si=9dSeEaWyBCoRw3dp) is probably a good idea. Or just get really comfortable with what height your releases are at and use that.

I was able to sling at the side of the FX Archery Chronograph successfully by releasing it within a few inches of the centerline every time, but I had to mark where my feet hit the ground to make sure I didn't whack the radar.

Let me know if you have more questions. I've used these tools quite a bit in recent years. Archaic Arms, Sarosh and Mersa can also all chime in here, as we all got the same FX Pocket Chronograph Mk 1 (until I lost mine )

I also have one of the cheap baseball chronographs (specifically this one: https://www.amazon.com/dp/B0D1X5Q5DX) and while it does the job, I wouldn't exactly recommend it.

You pretty much have to set it up in front of you since there is no voice readoff or storage. There is a button to show the last 10 readings, but then you have no idea which was which or even if it caught a bug flying by or something like that. And then because you have to set it up in front of you, you either have to leave it low and make peace with lower readings from cosine error, or prop it up high and risk hitting it.

It's much cheaper than the alternatives, but still not cheap enough to make it a good beginner purchase. Probably better to save your money for a little longer and get one of the better ones described here(although apparently the good ones aren't made anymore ).

The one positive I will say about this one is that because the front screen is so big and bright, it's a good option to set up under your target when you have a group of people throwing at the target. We did this at DSSC, and even though it's not a great absolute measurement because you get lots of drag over distance sapping away the speed(especially with tennis balls), it still gives you an interesting relative measurement between everyone's throws.

Oh, I'm glad there's interest in the topic!

A search turned up programming algorithms for tracking microchips, as well as options for expensive tracking systems or video post-processing. The idea is interesting, but it seems there's no finished product yet. I'm not yet sure if such systems will be able to clearly see stones in video, given the high speed and the small stones, and the background and lighting can vary widely.


It's great that you've used several devices and have such experience overall. Thanks for the advice. The part about the foil funnel for enhancing waves was interesting; I hadn't even thought of that.
I noticed the AA video with the radar, and so far I've only managed to get a lock once with the same radar position. It was a series of about 50 throws, and the radar detected about 28. And without forward protection, it seems dangerous. Incidentally, today I managed to lock almost all 50 throws in a continuous series while standing two steps in front of him and one step to the left. Even throws that went significantly sideways were recorded. Overall, the radar is good, but you need to somehow get used to throwing through it to see the results in front of you, or come up with something to see the results when it's behind you. The easiest way is to attach a mirror on a flexible stem.

I also came across a video on YouTube today featuring an interesting golf device, the Shot Scope LM1. Reviews say it's good, but I'm not sure if it's suitable for our needs.


The most frequent offer I've received from them so far isn't the FX Chronograph MK2, but the FX Pocket Chrono V2.
And 61 seems pretty high, too. My average is 54-55 so far, and today I've only had 5-6 shots above 60 out of about 100...


The Garmin Xero C1 can also measure the speed directly in front of the target, i.e., it measures the remaining speed before impact. If you add the projectile's weight, it adds kinetic energy calculations and some other readings, but this placement seems doubly dangerous. 

Pocket rock.et wrote on Jul 8^th, 2026 at 1:15am:

This is some crazy high speed with a 27 inch sling.

Has anyone ever tried to use a golf launch monitor to measure sling projectile speed? There are a lot of different devices out there based on radar technology. Some will display the numbers on the device itself, some of them have bluetooth connection and go with an app. The speed range should be fine for slinging. I think they measure club speed and ball speed and calculate other numbers from that, which a slinger just could ignore.

For example:
PRGR launch Monitor
rapsodo MLM
swing caddy SC200
flight scope launch monitor
...

I don´t know if they would just give you the ball speed when detecting no club speed. I also don´t know about the sensitivity of the devices, since they shouldn´t be placed too far from the "golf ball".

If anyone has experience with such a device, please let us know.