1st through 3rd Squadrons were formed as follows:
HHT (Headquarters and Headquarters Troop).
A,B,C (1st Sqdn.); E,F,G (2nd Sqdn.); I,K,L (3rd Sqdn.)were the Cavalry Troops.
D (1st Sqdn.), H (2nd Sqdn.), M (3rd Sqdn.) were the Armor Companies.
There was no J troop. (No self respecting Cav Trooper would want to be part of a Juliette troop.

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Each Combat Squadron also had an organic Howitzer Battery of M109's. They were known as How Battery. (How original.

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Each Combat Squadron also had an organic Engineer Company from the 58th Combat Engineers.
I can't really say what the Air Troop consisted of, other than what I've already said but it's all conjecture on my part.
I can't tell you exactly what the CSS Squadron consisted of either except that it contained higher level maintenance assets.
A Cavalry Combat Troop in 1989 in the 11th ACR consisted of the following:
HQ Platoon (Command elements were Black callsign on the radio, and the other units were Gold. e.g the First Sergeant was known as Black 7. The CO was Black 6.): 1 M1IP Abrams Tank. 1 M577 TOC Track. 4 M113 APCs. 2 M106 4.2" Mortar Carriers. 4 HMMWV's, 1 M88 Recovery Vehicle. 2 2.5 Ton Trucks. 1 2.5 Ton Maintenance Shop Truck. (I might have the number of M113's and Hummers wrong, but this is what my memory recalls.)
1st Platoon (Red Callsigns): 8 M3 Bradley CFVs.
2nd Platoon (White Callsigns): 4 M1IP Abrams Tanks
3rd Platoon (Blue Callsigns): 8 M3 Bradley CFVs.
4th Platoon (Green Callsigns): 4 M1IP Abrams Tanks
The Armor Companies consited of:
HQ Platoon: 2 M1IP Abrams Tanks, the rest was probably the same as the Cav Troops.
1st Platoon: 4 M1IP Abrams Tanks.
2nd Platoon: 4 M1IP Abrams Tanks.
3rd Platoon: 4 M1IP Abrams Tanks
They did not have a 4th Platoon.
I really don't remember what the Engineer Companies had except they had the M728 CEV's, and the AVLBs, and the MCLC's.
The How Batteries had 2 M577s, 6 M109 SP Howitzers, 6 M548 Ammo Carriers, 1 M88, and some other vehicles like a Cherry Picker (cant remember its designation), and some Gamma Goats (again cant remember their designation). I don't know what kind of organization these vehicles were in though.
HHTs had 2 M3 CFVs with them, and the rest was all M113's, M577s, and Trucks. I couldn't tell you what quantities of these were in them. I heard someone once say that they were supposed to have 2 M3's and 2 M1's in them, but 3rd Squadron only had 2 M3's that I can remember.
Once again, I'd reccomend asking the 11th ACR PAO. The squadron is still active in its new roll as OPFOR at Ft. Irwin, CA.
Cheers!
-Jim Taylor