I am looking for information about modernization of N001 Su-27 radar. As I have known, there are two different offers, one from Ukraine (Radionix) and the other from Russia (NIIP).
Ukrainian Radionix offers to replace N019-09 high-frequency receiver by N019-09R2 dual channel (Narrow-band & wide-band) high-frequency receiver, replace some other components and especially replace the N001-03 low-frequency receiver (signal processor) by new dual-channel (Narrow band at intermediate frequency (IF) of 28 mhz & wide-band at intermediate frequency (IF) of 84 mhz) low frequency receiver with new signal processors for air-to-air modes and air-to-surface modes.
Radionix explained that the narrow-band is for air-to-air modes while the wide-band is for air-to-surface modes and air-to-air long-range detection modes. below is their N001 modernization diagram:
Compare to old N001 diagram:
In the other hand, Russian NIIP has different approached way, using the by-pass channel concept. It means they keep all old systems for old air-to-air modes and add more components (by-pass channel) for new air-to-surface modes and new air-to-air mode (long-range detection mode). NIIP leaks very little information how they arrange the new components trap on the old components but N001-03VEP2 that they called digital dual-channel (low-frequency) receiver and Baguet-55-04.02 signal processor. Howver, when I read the N001-03VEP2 catalog, it receives the intermediate frequency (IF) of 28 mhz only instead of dual IF of 28 mhz and 84 mhz like Ukrainian Radionix concept.
Does NIIP uses only (narrow-band) IF of 28 mhz for both air-to-air and air-to-surface modes instead 2 IFs like Radionix?