ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2  All   Go Down

Author Topic: When a Combiner goes bad...  (Read 3174 times)

Andrew Broughton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1552
    • Check Check One Two
When a Combiner goes bad...
« on: February 14, 2018, 10:54:06 am »

1 P10T into PA821A

Good Combiner vs. Broken one...



Logged
-Andy

"Well, my days of not taking you seriously are certainly coming to a middle..."

http://www.checkcheckonetwo.com
Saving lives through Digital Audio, Programming and Electronics.

Scott Helmke

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1392
Re: When a Combiner goes bad...
« Reply #1 on: February 14, 2018, 11:48:05 am »

Wow, haven't seen that one before.  When I've had a bad PA821A it'll be one or more ports just not getting a full signal through.
Logged

Andrew Broughton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1552
    • Check Check One Two
Re: When a Combiner goes bad...
« Reply #2 on: February 14, 2018, 02:04:37 pm »

I'm very curious what goes wrong inside them that can cause this kind of grief.
Logged
-Andy

"Well, my days of not taking you seriously are certainly coming to a middle..."

http://www.checkcheckonetwo.com
Saving lives through Digital Audio, Programming and Electronics.

Henry Cohen

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 906
  • Westchester Co., NY, USA
Re: When a Combiner goes bad...
« Reply #3 on: February 15, 2018, 09:49:28 am »

I'm very curious what goes wrong inside them that can cause this kind of grief.

Presuming this is only one input channel, its amplifier stage is bad. probably overloaded at some point.
Logged
Henry Cohen

CP Communications    www.cpcomms.com
Radio Active Designs   www.radioactiverf.com

Andrew Broughton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1552
    • Check Check One Two
Re: When a Combiner goes bad...
« Reply #4 on: February 15, 2018, 08:49:17 pm »

Makes sense. Yes it was just one input.
It was tough to diagnose without a scanner.

Thanks, Henry.


Sent from my iPhone using Tapatalk Pro
Logged
-Andy

"Well, my days of not taking you seriously are certainly coming to a middle..."

http://www.checkcheckonetwo.com
Saving lives through Digital Audio, Programming and Electronics.

David Pedd

  • Full Member
  • ***
  • Offline Offline
  • Posts: 108
  • Gilbert, AZ
Re: When a Combiner goes bad...
« Reply #5 on: February 15, 2018, 09:46:17 pm »

Presuming this is only one input channel, its amplifier stage is bad. probably overloaded at some point.

Went to a Shure seminar yesterday.  Great info.

The Shure man demonstrated how you overload the receiver front end by using the paddle antenna when you don't compensate for the db overload.

I'm guessing the same type of overload could fry the combiner.

Logged

Lyle Williams

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1556
Re: When a Combiner goes bad...
« Reply #6 on: February 17, 2018, 07:20:53 am »

An attenuator is one of the most useful RF debugging tools you can own.
Logged

Andrew Broughton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1552
    • Check Check One Two
Re: When a Combiner goes bad...
« Reply #7 on: February 17, 2018, 11:03:47 am »

An attenuator is one of the most useful RF debugging tools you can own.
I'll bite... Could you elaborate?
Logged
-Andy

"Well, my days of not taking you seriously are certainly coming to a middle..."

http://www.checkcheckonetwo.com
Saving lives through Digital Audio, Programming and Electronics.

Henry Cohen

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 906
  • Westchester Co., NY, USA
Re: When a Combiner goes bad...
« Reply #8 on: February 17, 2018, 07:36:22 pm »

I'll bite... Could you elaborate?

As a quick diagnostic tool to see if any part of your signal chain is being overloaded (with saturation of the subsequent gain stage) and causing problems which can appear as co-channel interference.

They are also indispensable when gain balancing a distributed antenna system.
Logged
Henry Cohen

CP Communications    www.cpcomms.com
Radio Active Designs   www.radioactiverf.com

Lyle Williams

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1556
Re: When a Combiner goes bad...
« Reply #9 on: February 18, 2018, 07:09:01 am »

If you add (say) 6dB of attenuation and your problems drop by more than 6dB, something is operating outside it's linear operating range.
Logged

ProSoundWeb Community

Re: When a Combiner goes bad...
« Reply #9 on: February 18, 2018, 07:09:01 am »


Pages: [1] 2  All   Go Up
 



Page created in 0.098 seconds with 22 queries.