Let's talk radar chronographs

[Justaguy]

I'm old fashioned. I do not see the value of a high end radar chronograph. They are too expensive and add NO more value or accuracy over the garden variety sun screen type that you can buy from China at $70 or less. Please consider your usage. You only need a crono for tuning purposes. Once that is done, you put it away and do not use it until you do more tuning. Then there is is the accuracy thing. The old fashioned sun screen type with a clock over a known distance will always be more consistent than a radar model. When it comes to accuracy, there is no comparison. If the clock is accurate, so is the speed displayed. Then is accuracy really important and the answer is no, it isn't. What you really need is consistency, because the displayed number is relative to accuracy and repeatability at the end of the day. Don't waste your money.

Some guys just like to have cool toys.

I bought the Labradar on sale for $350. I don't NEED it, but I sure do like it.

 

[GeneT]

The LabRadars are going for $200 and lower now! I kinda wanted to try out a Garmin, but hard not to consider a LabRadar at that price… until I ask myself why is everyone selling them?

Because the Garmin is much faster and easier to set up, and in my experience (echoed by many others) it never misses a shot (LR does, and optical chronys certainly do, particularly if lighting is poor). The Garmin (and new LR) are also small enough to just keep in your range bag, so you always have it with you and don't have to "plan" to have a chrono session. It's just there in your bag if you suddenly start questioning your velocity, or want to help out a friend.

I've owned a lot of chronos, including the original Labradar and now the Garmin. The Garmin (and presumably the new LR) isn't just the newest toy - it's a markedly superior device in pretty much every way.

GsT

 

[AlanMcD]

It is your money and you can do as you wish with it, but all the features you mentioned can be done with the conventional crono and even though the radar units advertise BC, it really cannot because the point where the second speed reading obtained is only a best guess of distance, it cannot be relied upon as accurate. BC can only be calculated with two separate cronos at a predetermined distance apart. At the price difference between the two types, I can buy many conventional cronos and still be way under budget.

Sorry, but again much of this is just wrong . . . your description of the distance as being a "best guess" oversimplifies the fact that it is a mathematically calculated property using known physics and an accurately measured distance to the projectile via Doppler radar (speed is calculated off the rate of change of this data). Furthermore, it does not give just a "second reading" at a "best guess distance", but the speed and distance of the projectile every 0.002 seconds (once detected) for potentially well over a hundred data points (depending on the range to target) all with an known signal to noise ratio - data that can be easily fit and analyzed with a polynomial regression (if desired) for an even more robust pair of values to use for BC calculation via distance between readings.

By the same logic, one could call the distance used in your calculation with multiple conventional chronographs as just a "best guess" value as well - especially if measured with a laser range finder (same tech, different wavelength) . . . which is nuts because if we are measuring something out to fifty yards or so we would most likely use that as the "better" data given the difficulty and time involved in doing it with a tape.

I'm not saying that radar units are superior to conventional units in every case - they are not. Probably the best example being where one wants to know muzzle speed in a very confined indoor space, like maybe in a few feet while testing in a room like a work shop on a bench - the radar is not going to be able to do that. But I do feel that people should be told the correct facts without bias so that they can make their own determination what to buy. For data geeks like me they are a very useful tool. I lived with one conventional chrony for many years, but I find this new option to be very useful, if admittedly more expensive. I'm not saying anybody needs to choose one, but at least understand what the choice actually is . . .

 

[steve-l]

Sorry, but again much of this is just wrong . . . your description of the distance as being a "best guess" oversimplifies the fact that it is a mathematically calculated property using known physics and an accurately measured distance to the projectile via Doppler radar (speed is calculated off the rate of change of this data). Furthermore, it does not give just a "second reading" at a "best guess distance", but the speed and distance of the projectile every 0.002 seconds (once detected) for potentially well over a hundred data points (depending on the range to target) all with an known signal to noise ratio - data that can be easily fit and analyzed with a polynomial regression (if desired) for an even more robust pair of values to use for BC calculation via distance between readings.

By the same logic, one could call the distance used in your calculation with multiple conventional chronographs as just a "best guess" value as well - especially if measured with a laser range finder (same tech, different wavelength) . . . which is nuts because if we are measuring something out to fifty yards or so we would most likely use that as the "better" data given the difficulty and time involved in doing it with a tape.

I'm not saying that radar units are superior to conventional units in every case - they are not. Probably the best example being where one wants to know muzzle speed in a very confined indoor space, like maybe in a few feet while testing in a room like a work shop on a bench - the radar is not going to be able to do that. But I do feel that people should be told the correct facts without bias so that they can make their own determination what to buy. For data geeks like me they are a very useful tool. I lived with one conventional chrony for many years, but I find this new option to be very useful, if admittedly more expensive. I'm not saying anybody needs to choose one, but at least understand what the choice actually is . . .

First I have been in the radar business for better than 60 years. I do understand the technology and because I do, I made those statements. The return signal amplitude of a pellet at any distance beyond 50 meters with the very weak transmit power used would be almost undetectable. It is the physics that I'm going by. I suspect that the return echo from a pellet much beyond 20 meters would be lost in the background receiver noise. That's why any BC calculation would be a WAG at best. On the other hand, A conventional sun screen crono at the muzzle and another one at the target at say 100 meters would be more than accurate enough to do the BC arithmetic and get a repeatable result, but again, it's your dime.

On edit, I should also add that the Chinese also include a spare LED light source at no extra cost, just in case you shoot one up at distance. On second edit: Not only is the transmitter very weak, the transmitter pulse width needs to be extremely short not to block out the receiver at short distances. (Consider a radar mile (two way) is 6.36 micro seconds). This fact greatly exasperates the ability to perform a BC calculation.

 

[AlanMcD]

First I have been in the radar business for better than 60 years. I do understand the technology and because I do, I made those statements. The return signal amplitude of a pellet at any distance beyond 50 meters with the very weak transmit power used would be almost undetectable. It is the physics that I'm going by. I suspect that the return echo from a pellet much beyond 20 meters would be lost in the background receiver noise. That's why any BC calculation would be a WAG at best. On the other hand, A conventional sun screen crono at the muzzle and another one at the target at say 100 meters would be more than accurate enough to do the BC arithmetic and get a repeatable result, but again, it's your dime.

On edit, I should also add that the Chinese also include a spare LED light source at no extra cost, just in case you shoot one up at distance. On second edit: Not only is the transmitter very weak, the transmitter pulse width needs to be extremely short not to block out the receiver at short distances. (Consider a radar mile (two way) is 6.36 micro seconds). This fact greatly exasperates the ability to perform a BC calculation.

Ok - that makes a lot more sense . . . thanks for clarifying it. I appreciate knowing it comes form direct experience in the field.

I'll admit have not used mine out past about 50 yards yet, but the data I have from it with .22 pellets seems very robust, with good usable S/N values (it's even better with .25 pellets). I do have some .22 data out to 100 yards that someone sent me, and it looks good out to about 75 yards but gets sketchy after that. I don't know how the radar companies did it, but the data does seem to be meaningful a good ways beyond 20 meters - to at least a bit over double that (although that is with a .22 - I did a bit of a trial with a .177 and it was no where near as good; that might be about 20-25 meters or so). I'm happy with working with data under 50 yards for the BC work I want to do with it as I mostly shoot .22 caliber. More distance would be better, but this is a great start. I do have the higher power USA model - I doubt the lower power versions would do anywhere near as well.

I went down this path because I had done some testing with my Chrony at a distance to gather data to analyze, but since I only have the one I had to work on string averages at both the muzzle and down range, at least as a starting point. What I observed kind of blew me away - I was finding a significantly higher ES down range vs. at the muzzle. Logic would say that if BC was anything close to constant, it should be less down range because of the amount of total speed scrubbed off - proportionally, the % ES would result in a lower number at slower speeds after having flown down range. But since it was the opposite, I thought through it long and hard and the only thing I could come up with as a cause would be variation in BC from shot to shot.

Since I did want to investigate this phenomena, and to do it properly I had to be able to work on individual shots, not averages of shot strings. I was left having to decide whether to get multiple conventional chronies or try the radar approach. I sat on the decision for a few years as the original Lab Radar was very interesting but was quite a bit of money at the time - but with the price drops from the next generation launching I was willing to give it a try. I'm glad I did, and am happy with it for my uses. I'll probably upgrade when the third or fourth generation comes out.

 

[steve-l]

Ok - that makes a lot more sense . . . thanks for clarifying it. I appreciate knowing it comes form direct experience in the field.

I'll admit have not used mine out past about 50 yards yet, but the data I have from it with .22 pellets seems very robust, with good usable S/N values (it's even better with .25 pellets). I do have some .22 data out to 100 yards that someone sent me, and it looks good out to about 75 yards but gets sketchy after that. I don't know how the radar companies did it, but the data does seem to be meaningful a good ways beyond 20 meters - to at least a bit over double that (although that is with a .22 - I did a bit of a trial with a .177 and it was no where near as good; that might be about 20-25 meters or so). I'm happy with working with data under 50 yards for the BC work I want to do with it as I mostly shoot .22 caliber. More distance would be better, but this is a great start. I do have the higher power USA model - I doubt the lower power versions would do anywhere near as well.

I went down this path because I had done some testing with my Chrony at a distance to gather data to analyze, but since I only have the one I had to work on string averages at both the muzzle and down range, at least as a starting point. What I observed kind of blew me away - I was finding a significantly higher ES down range vs. at the muzzle. Logic would say that if BC was anything close to constant, it should be less down range because of the amount of total speed scrubbed off - proportionally, the % ES would result in a lower number at slower speeds after having flown down range. But since it was the opposite, I thought through it long and hard and the only thing I could come up with as a cause would be variation in BC from shot to shot.

Since I did want to investigate this phenomena, and to do it properly I hacd to be able to work on individual shots, not averages of shot strings. I was left having to decide whether to get multiple conventional chronies or try the radar approach. I sat on the decision for a few years as the original Lab Radar was quite a bit of money at the time, but with the price drops from the next generation launching I was willing to give it a try. I'm glad I did, and am happy with it for my uses. I'll probably upgrade when the third or fourth generation comes out.

Trying to put this all together, The radar crono is certainly more convenient and therefore easier to use. I cannot deny that, but they will not be as accurate or consistent as the sun screen variety. However, an argument can be made for the need for accuracy. I don't think it is important for an air gun. Yes, I hear folks using them at extraordinary distances, but that is not the role they are best in even though I play with distance from time to time for fun.

Pellets are still the ammunition of choice for the short intended distances of the typical air gun role and there lies the issue you were dealing with. Diabolo pellets are drag stabilized not spin stabilized. In fact that is a point of contention, but that is for another discussion. A pellet being drag stabilized is much more susceptible to atmospheric conditions like wind humidity and air density, but a pellet's best attribute is its energy loss over distance. In the typical air gun role, you want the pellet's energy to dissipate quickly for safety reasons. That's a good thing. If you want to shoot at MOA accuracy at 100 meters, you had better have perfect atmospheric conditions. When you don't have that, you have deviation