449.425

7/29/07

		Technical Specifications
		control codes: 10* turns off PL 11* turns on PL

SYSOP (password required)

7/21/07 K2LM, N1FGY and KJ1K The cavities were removed and the adjustment screws were cycled in and out many times to "clean up" the effects of age and weather that have caused problems with the cavities. The cavities were then retuned, reinstalled and the repeater power output was increased from 20
watts (the maximum prior to tuning that would not cause desense) to 40 watts. A test of the repeater showed desense does not occur at full power output (measures as 86 watts). Tuning data is as follows:

Before cleaning/tuning:

Input = common, output = Rx:
    444.425    IL = 1.79 db @ 0 dbm drive
    449.425    Rej=-74 db @ 0 dbm drive
    449.425    Rej=-91 db @ -20 dbm drive

Input = common, output = Tx:
    449.425    IL = 1.42 db @ 0 dbm drive
    444.425    Rej=-73 db @ 0 dbm drive
    444.425    Rej=-91 db @ -20 dbm drive

K2LM noted that the Tx rejection was non symetric, indicating that the two
Tx cavities were not tuned to the same frequency

After cleaning/tuning:

Input = common, output = Rx:
    444.425    IL = 1.56 db @ 0 dbm drive
    449.425    Rej=-73 db @ 0 dbm drive
    449.425    Rej=-90.4 db @ -20 dbm drive

Input = common, output = Tx:
    449.425    IL = 1.56db @ 0 dbm drive
    444.425    Rej=-74 db @ 0 dbm drive
    444.425    Rej=-93 db @ -20 dbm drive

Tx rejection is now symetric as it should be.

Much thanks to K2LM for coming to help us and for bringing his wonderfull HP
analyzer with him.

Pictures take of Ed and Jim performing the cleaning and adjustment of the 449.425 duplexer.

News: 10/03/06

Added a ground between the Radio and the controller to silence the fan wine.

older news: 9/29/06

Perfectly operational
Rebuilt antenna
repaired hardline and NEW jumpers
Two rack jumpers replaced.
rebuild/retuned receiver w/Krylon
NEW, as in never used before 100watt PA running at 40watts
desense cut off is at 52watts.
retested Circulator
Some ham mods to the exciter and the Zmatch board was removed.
Added Fans to the PA that are controlled by the controller to reduce heat and avoid 24x7 power usage.
removed all unused wire and soldered anything that was connected using the alumnium amp connectors.

Basicly this repeater has been rebuilt/retuned and is in tip top shape.

OLD NEWS:
449.425 stuff that needs to be done.

In approximate order of how we can get into trouble

4/10/06 Antenna/feed line bad 10 to 1 SWR.
PA is not putting out properly?

4/12/06 K2AEP, KJ1K, N1FGY all worked on receiver and antenna problems.
4/13/06 KJ1K

Fixed ID, FCC requires an ID
installed a backup antenna

4/19/06 KJ1K and N1FGY installed a circulator.
4/26/06 6meter crew installed the Squelch mod to 449.425 while they were there.

Circulator:
RJ Communications Products Inc
Model HI-460-B SN 8824
Tested ke3ht 4/14/06
422mhz - 500mhz
0.18db - .25db forward insertion loss
Return Loss forward = -25db (with and without a load on the output)
Insertion loss reverse from antenna port to xmitter port 33db @ 449.425mhz
Insertion loss reverse from antenna port to xmitter port 11db @ 347mhz
Insertion loss reverse from antenna port to xmitter port 11db @ 543mhz
Lots of loss above 1ghz.