Makes sense - unfortunately, I have the gun and it's just going 'ok'.
Maybe I'm missing something; the info on the targeting was helpful, though I'm still a little unclear between the crosshairs, and the dot in the middle of targeting near it.
Another mystery currently is why nearly all my hits with the SU-26 or even my TD's seem to be doing only 0 to 10% damage. I've had a number of artillery appear to hit right on in a row each doing 2% damage. I've had the game say 'critical hit' or similar indications of a good hit with as little as 0 damage.
I usually drive a ways into the map now to be able to hit more. Of course some maps have a lot of barriers blocking artillery. Hitting moving targets is still, er, hit and miss.
With this gun doing '150/270/270' damage (not sure what that means) I'm even more surprised at all the hits doing so little damage.
My tank destroyer can hit a tank right in the side and do 10% damage a couple times, then the tank one shots the TD head on. Who knows.
For example that just happened, my TD was waiting as a tank moved, then I shot it four times, getting it to 12%, and he seemed to one-shot my AT-1. Not sure what he was.
Sometimes it does more, occasionally 80%, even a few one shots I think, I thought there'd be a lot.
The targeting reticule seems to need a while when I move the target much; while I'm waiting 5 seconds for it to target someone else kills it usually.
I'm not sure how they're targeting so fast if artillery - if maybe they're shooting before the circle shrinks.
I'm saving for the 700 range tier 9 radio; it's expensive at 5600 to research. Hope it's a big help.
I'm still getting a feel for when the targeting circle is broken up, part on the enemy part not.
You have a lot of questions. Almost all of them can be answered by the wiki, but I'll save you the trouble with a few.
Targeting time: you can buy a gun laying drive (module) to speed that up, but what you really need is an experienced gunner and commander. The gunner should be obvious, and the commander gives a bonus to the rest of the crew in addition to determining your view range. The difference between a 75% and 100% crew is large, the difference between a 50% and 75% crew is absolutely huge. I don't recommend spending gold on crews until you get to t5 or so, but at this stage it is absolutely worth it to at least get your commander to 75%. If you really like artillery you should at least get the gunner and loader up there too.
Where the shell goes inside of the reticule is determined by a normal distribution, the tightness of that distribution is affected by your gunner's skill. In short, a better gunner makes the shot go to the middle of the reticule more often, in addition to making the reticule itself collapse faster.
As for missing, just don't fire until your reticule is either smaller than the target or as small as it will get, and don't forget to lead your shots. Pushing caps+0 turns on another reticule that shows you where the server thinks you are pointed (and thus where the shot will really go), using that will help a lot when you have to make quick shots.
Low damage, and low damage critical hits: First, critical means you damaged a component or crewman, doesn't say anything about actual HP damage to the target.
Second, HE (which artillery shoots almost exclusively) is not at all like AP. If it penetrates (which it normally doesn't) it does full damage to the target. If it doesn't penetrate the damage is halved, and then 1.3 points of damage is subtracted for each mm of armor on the target. So, for example, if you hit the front of a KV's hull at a flat 90 degree angle shooting a shell that does 150 damage: You will almost certainly not penetrate, so potential damage is halved to 75. 75 is how much armor the KV has on its frontal hull, so 97.5 is subtracted from your damage. Since you can't do negative damage you will do zero damage. It's possible that the same shot could splash damage onto his gun, and you could have a "zero damage critical hit."
The KV is a t5 heavy and you will see plenty of them in your su26 (thank the matchmaker). However if you shoot the more expensive ammo that deals 270/shot, in the above situation, you would deal 37.5hp damage (about 6%) to the KV. That's not good, but that is frontal armor, and artillery shells tend to land on their tops where the armor is weaker, so in practice (with the good ammo) you can expect to do some meaningful damage. That said, it is important you use the better ammo, 150/shot just won't cut it. (To be clear, I don't mean gold ammo, I mean the more expensive silver ammo).
Once your crew is reasonably skilled you should start to get a feel for flight time. Once you have that down you can start taking shots at moving targets. At its tier the ability to accurately hit moving targets is fantastic, because nothing at t3 is truly slow, and so it is usually moving. In addition, with its nice pen of 61 you will be able to penetrate their fast units, and once you can accurately hit them while they are moving you will start to get a lot of kills. So, even if you find yourself unable to adequately damage that KV you should be able to kill his support off, allowing your team to swarm him.
Better radio: Radio is very important for artillery, even with your limited range. It will help quite a bit.
AT-1 being ineffective: AT-1 is great for its tier (but only for its tier), the main problem is probably the matchmaker throwing you at things you have little hope of damaging, especially with the stock gun. Training your crew will help a ton. But, do make sure you are using the best guns and the right ammo for the situation. Regardless of that, expect to die when you are shot by basically anything as that is the life of most TDs.
The AT-1 has two great guns, the 76mm and the 57mm. The 76 should shoot HE, the 57 AP. 57 has great penetration, decent damage, good accuracy, and great RoF. 76 has a really strong punch and medium-bad accuracy and RoF. The 76 shines because at t2 nothing has much armor, and your HE will often penetrate, KOing targets in one shot. The 57 is something to use if you like longer shots, or if you keep finding yourself in t3-4 fights because its pen will allow you to do some damage to those tanks. Whichever gun you use, you should never be leading a push, you are just too squishy for that.
For those interested in the HE math, here is a
link.
And, Craig, for specific questions you would probably be best off searching for the answers on WoT's forums.
http://forum.worldoftanks.com/ They have a forum for each class of each nation's tanks, so you can almost always find a thread about the specific tank you are asking about.