Friendly fighter radar interference?

[GalmOne 1]

I read somewhere that the radar sets on F-4J Phantom II's had to be adjusted to different frequencies all within the X-band, and that there were only 18 channels available (at least during certain ops) during the early 70's. This makes me wonder whether it was possible then to send up only a small number of planes together since they could all interfere or overload each other's radar sets. If this is the case, are later Cold War jets (like the F-14, F-15 etc.) limited to this as well?

 

Here's the excerpt I found it from:

 

t was always fun when we got a "new" bird - nOT! You F/A-18 fixers don't know what you missed; it doesn't even concern you nowadays. If the pilot or RIO sees co-channel interference from another plane, he just pushes a button to change channels. That wasn't so in the good ol' F-4J's and F-4S's, as they were "manually" tuned.

There were 18 frequencies used, all X-band (9ghz), and since you had 12 birds in a squadron, the odds of getting a new bird in a "wrong" frequency was really high. You wouldn't want to send out a flight of Phantoms that were closer than 2 channels from each other, because the radars would pretty much "jam" each other, or overload each other's receivers with radar energy. So, we'd get to re-tune 'em, which meant a buttload of work:

1) Open the radome, insert the package extension rail.

2) Extend the radar package after removing the 4 nuts from the X-frame.

3) Connect air conditioning from the -8 and power from the -60

4) Select the channel range on LRU-6A2

5) Select the channel range on the 4A3A7 board.

6) R&R the two filters out of the 2A8 (Receiver)

7) Wait for COM/NAV to replace the filters in the turtleback

8) Fire up the radar, warm it up until the transmitter kicked in (5 minutes)

9) Re-tune the main KPA (Klystron Power Amplifier, 1,525 watts) by adjusting the four struts, de-tune strut #3 to obtain maximum power

10) Re-tune the CW Illuminator KPA using same procedure (the CW Illuminator generated the RF signal the Sparrow missiles followed to their target)

11) Button it up, and you're done ... but put a new set of KPA's on order, because they don't like being tuned to a new frequency, and you can bet your arse you'll be putting in a new set within two weeks. Oh, joy! Roll Eyes Wink

 

Such were the joys of a 'Nam-era F-4 radar tech We busted are azzes, and learned a lot.

Funny, I hadn't worked on one of those birds in 25 years, but still have the routine pretty well down pat Wink

 

S/F,

 

Wook

 

from http://www.secretpro...php?topic=149.0

Edited September 25, 2012 by GalmOne