1South west side approach
A reasonable spot is along highway 62 westbound. It takes a fairly long drive when coming from Esfahan before you are able to make a u-turn. You have to pull over on the north side just when the road is gradually sloping down. Depending on the way the helicopters are parked, you will be able to read some of them.
2South east side approach
Another spot is on the western parallel road that runs along 65 southward. It is higher and it can be accessed in various places, on of which doubles as the bases' main entrance. Although there are sand hills inside the fence, there is one spot were you can have a peek between them. You will now see the western part of the ramp head-on, rows of Bell 206 can be seen. Onfortunately, you will be looking towards the gate of the base and this spot is about 25 metres from a guarded watchtower from the revolutionary guard complex behind you... Only a short stop and hopefully they have some of their serial on the nose.
3South west appartment buildings [RISKY]
Probably the best spot, albeit a bit risky and hard to enter, are the appartments in the residential area to the southwest of the base. The eastern side of this area is lined with appartment buildings of sufficient height. From there you will just be high enough to see over the earth walls that line the inside of the base fence. The northern most appartment is about 900 yards from the southwestern edge of the ramp. Late afternoon light and a lot of luck, there are bound to be military residents here, should provide some serials. Access to these building is difficult, they have fenced off parking lots in the basement and some have shops on the ground floor.
4Old base
An alternative to spot 1 and probably the most 'relaxed' when they are flying is finding a spot on the old south base. There used to be an access road off highway 62, but that is closed down now. So you have to go south a bit further on the parallel road of 65 and cross it following the signposts to the railway station. After crossing the 65 you will get a roundabout, do not go back onto 65 northbound but straight. At the t-junction make a left towards the old access gate. Before you reach the gate, go right on the sand path. At some points you will have comparable views to spot 1 although the distance is greater and you are a bit lower. The terrain is bordered by a wall with holes in it, so a poke or two might yield results.
Alternatively, stay near the gate in the old guard house for example. From there the flying activities on the western side can be watched.