Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 90; Flight Crew Total 8000; Flight Crew Type 700
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
General None Reported / Taken
Aircraft; ATC Equipment / Nav Facility / Buildings
During the descent and joining of the LYNXX 8 STAR; we the crew were assigned to cross 5NM east of the HEC VOR at FL240; then we were given instruction to contact Los Angeles Center on 135.2 MHz. Immediately upon switching to make contact; there was a loud background noise that would best be described at a loud squeal or tone. I; the pilot monitoring; made the radio call to ATC with our assigned restriction. ATC was able to hear us; however their transmission was extremely difficult to hear. Upon ATC's initial response they gave us an assignment to 'make the crossing at HEC'; which was barely intelligible. The STAR has a published 'EXPECT' clearance of FL240 at HEC. I attempted to clarify the instruction as we were rapidly approaching our assigned restriction; but between radio traffic and the very loud squeal/tone; it was difficult to understand ATC. We were then given another instruction to descend lower prior to HEC; which again I had to clarify due to the radio noise issue. We understood the instructions to make our crossing assignment 5NM east of HEC and then to the lower altitude. We did not cross HEC at the published 'EXPECTED' altitude due to the confusion. Shortly after this we were handed off to Joshua Approach; and experienced no further issues with radio noise/interference. We did inform Los Angeles Center multiple times of the issue with 135.2 MHz. At no time was there a traffic risks/loss of separation.As an additional note; the next day the same crew departed Southern California over roughly the same route; and we were again assigned 135.2 MHz for ATC. We had the same noise issues again but fortunately we were able to get a new frequency quickly. At no time did we experience the issue on any other frequency anywhere.
[Report narrative contained no additional information].
CE525 flight crew experiences a loud squeal on ZLA frequency 135.2 making communication nearly impossible. After switching to a new frequency comm returns to normal. During the next day's departure the 135.2 frequency is again assigned with the same results.