[evlatests] Fwd: #9 frm

[Chuck Kutz]

Jim Jackson wrote:
> Chuck,
>
> FYI.
>
> Jim
>
>> Date: Thu, 06 May 2010 10:19:22 -0600
>> From: Dennis Mobley <dmobley at aoc.nrao.edu>
>> Organization: NRAO
>> User-Agent: Thunderbird 2.0.0.23 (Windows/20090812)
>> To: Jim Jackson <jjackson at aoc.nrao.edu>
>>
>> Jim,
>> Antenna 9 has ripped the P-band cable out of the FRM trombone assy. 
>> When this occurs the rotary joint bearings fail/lock-up. The rotary 
>> connects the subreflector tube and subreflector allowing for the 
>> 327Mhz dipole cabling to be free from rotation. Antenna 24 did this 
>> last year, now antenna 9. This could be a signal for a possible 
>> systemic failure of the Kaydon precision bearings used in this joint 
>> on all of the antennas. I spoke to John Wall. He feels after 28 years 
>> with no external provisions for lubrication the bearings failure is 
>> eminent for the rest of these rotary joints, with the P-band cable 
>> being destroyed.
>>
>>
>> Dennis
>
All,

 From Front End Group's perspective:
When this incident occurs; we loose the DC power cable, the AC power 
cable and the two heliax signal cables. When this happened on antenna 
24, we also blew up both the P-band receiver and the 4-band receiver.

I am not so comfortable with these occurrences being eminent.



Sincerely,

Chuck Kutz