I got a photo of the KMS-4 sat and started wondering about the possible frequencies based on what could be antenna.
I wrote an email to the amsat-bb a while ago which I will repeat below. You should note there has been no reported emissions, and the photos linked below may have been from a model made for the press, so may have had fake/non flight hardware. The photos are also from the previous launch a few years ago.
Where did you get the photos you linked to and when were they taken/broadcast?
---------------------------------------------------------------------------------------------- Not sure if it has been posted yet, but there is a good technical write up of previous North Korean satellites here:
http://38north.org/2012/09/nhansen091212/
Some sites suggest 450 to 470Mhz is likely band. Ideally would need a very high gain setup with a wideband SDR dongle to see any transmissions. If they wanted they could turn all transmitters off unless commanded or else only when the GPS says they are within range of the ground station. Note the article linked is only the older satellites.
I don't believe there was any public reception of actual emissions from previous models. It does look likely UHF will be used. In this day and age if it does emit on UHF constantly someone probably will detect it and share. with possibly 6 UHF antennas there may be multiple downlinks. I will buy a pint for whoever decodes the GPS location downlink first!