AS-1289 RF noise heard on receiver

[ag7c - Pete]

I just received my new AS-1289 Ant Switch.
Seems to work FB.  Very nice addition to the remote shack.
2 issues were noted, however:

 1. With no antennas connected, only the transceiver connected on COM and the AS-1289 powered up, a lot of RF hash noise is conducted on the COM coax to the transceiver.   By making sure the AS-1289 logic board is grounded to the case, the noise on RX is gone and all TX tests good with under 100 watts TX on different antennas and also a dummy load.

 2. There is a trace on the top of the logic board which is is much too close to the underside of a mounting screw head.  Could be a problem if the soldermask gets scraped away and the mounting screw head contacts the pcb trace.

73
Pete
AG7C

[SM5DXU]

Pete, I've got the same kind of receiver noise after installing the AS 1289. Where did you make the ground connection?

/ Göstha

[ag7c - Pete]

I removed all cables and power from the AS-1289.  I removed the case top.

I removed the 2 mounting screws for the logic  board.  Turning the board over, I carefully scraped away the soldermask on the copper ground plane in a ring around each of the 2 mounting screw holes.  Just enough to mate with the metal standoffs.  I tinned the bare copper.   Then I remounted the logic board with the 2 mounting screws.

Pete
AG7C

[SM5DXU]

Thanks Pete! I'll copy your solution and report the result. My remote QTH is 50 km away, so the work will have to wait until my next visit there.

/ Göstha

[sm2o]

Hi

I tested to do the same modification and I could also register an improvement when it's done, so we will make the change manually from now on, and change the PCB from next batch, TU

73 de mike

[ag7c - Pete]

Thanks for the update Mike.   As I mentioned, the AS-1289 is certainly a nice addition to the Radio site here.
Sure would like to have a one and only one antenna selection mode, though.   

Pete
AG7C

[ag7c - Pete]

Sorry Mike,

I meant the ability to select  whether I would have one and only antenna selected or not on the Set Antennas page.

Pete

[sm2o]

Hi, You mean that you want to be able to select more than one antenna at the time ?

/mike

[ag7c - Pete]

Hi Mike,
Yes.  I was thinking of receive only situations with multiple antennas or for certain test setups here.
But then I realized everything is working FB as is and the idea may not be that important to anyone else.

Please forget I mentioned it.

Pete
AG7C

[SM5DXU]

Now I've made the modification you suggested, Pete. What a difference it made! All hash noise disappeared.

Thanks a lot and 73,

/ Göstha

[ag7c - Pete]

Thanks for the update Göstha.
Great to hear that you had good results.

73
Pete
AG7C

[EA7EU]

Have you any picture¿¿¿???

I removed all cables and power from the AS-1289.  I removed the case top.

I removed the 2 mounting screws for the logic  board.  Turning the board over, I carefully scraped away the soldermask on the copper ground plane in a ring around each of the 2 mounting screw holes.  Just enough to mate with the metal standoffs.  I tinned the bare copper.   Then I remounted the logic board with the 2 mounting screws.

Pete
AG7C

[sm2o]

Here is some more info about improvements of the AS-1289

http://www.remoterig.com/wp/?page_id=2706

73 de mike

[ag7c - Pete]

Hi folks at RemoteRig,
Thanks for continuing to make the AS-1289 a better unit.  I also noticed relay chatter on 6mtr SSB at 100 watts.  Similar to your Ver1.3 fix, I installed 0.01uF 50V ceramic caps on each relay control line and 0.1 uF 50V ceramic cap on the +12V line to the relay board.  No more relay chatter noticed  The AS-1289 continues to do an excellent job for my remote station.  Bypassing and shielding are most important, especially in an antenna switch box.  Values for the bypass caps allows a little bit of leeway but soldering certainly requires a steady hand and a magnifying lens (for most of us anymore).

Pete
AG7C

[Jan (Microbit)]

Thanks for your feedback!