Mode Selection

This information is edited from a repost of an acig.org forum post by mrdetonator:

http://www.secretprojects.co.uk/forum/index.php/topic,25.msg59.html#msg59

The radar scan modes БСВ, БСВ-ΔH4, БСВ-ΔH1, СМВ, МВ are switched automatically according to aircraft altitude Hs (DV-30 barometric probe) and the antenna position ”ΔH” switch.

"БСВ СЦ-R-БСMB" switch

The scan mode БСВ-СЦ can be selected manually by the pilot with the radar mode switch in the "БСВ-СЦ" position.

e.g. the aircraft is flying with its nose below the horizon (descending), but the antenna bearing is above the horizon.

At an altitude of 1500m the БСВ mode changes to СМВ automatically.

If the antenna elevation is below the horizon under the same conditions (descent), at an altitude of 1500m the БСВ-ΔH1 mode switches to the МВ automatically and vice-versa.

The БСВ-СЦ mode does not have altitude limitations, the "ΔH" switch does not have an effect on it.

NAVED "АВТ/РУЦЧН" Switch

Set to "АВТ", the radar mode selection is done automatically by the GCI datalink (ARL-SM).

The radar scan patterns under GCI are better optimized due to known PPS/ZPS aspect.

The one-way commands from GCI are displayed on special symbol indicator mounted on the ASP-23DE gunsight.

Set to "РУЦЧН"Pilot, interrupts the GCI datalink.

Click on this photo to zoom in and look at the small black panel to the lower right.

This is very similar to the switches discussed above.