airtraffic

Author Topic: KISM Status  (Read 8388 times)

Offline TonyP123

  • Newbie
  • *
  • Posts: 8
KISM Status
« on: March 15, 2013, 08:01:50 AM »
Well, I don't know long this has been the issue on the feed. I noticed the multiplexer for my antennas took a dump. It's been introducing a hum into the radios, to which it's being transmitted into the feed. I pulled it out of the antenna line and made a direct connection to the receiver. I will try to improve my signal to my radio by duplexing another antenna to the radio as a band-aid  ...1dB increase would make my happy.. Weekend project.

I have also added a noise filter into the audio cable between the radio / computer. This should have adjusted my audio unbalance between the two. I will work on tweeking the filter this weekend. Built a 50 dB PAD filter and I will replace the fixed value resistors with a var-resistor. If I can get rid of the hiss, I will do cart wheels. lol

Thanks to the KISM listeners for you patience.  :-) 
tony



Offline dave

  • Site Founder
  • Administrator
  • Hero Member
  • *****
  • Posts: 4593
    • LiveATC.net
Re: KISM Status
« Reply #1 on: March 15, 2013, 08:03:05 AM »
Thanks Tony!

Offline InterpreDemon

  • Hero Member
  • *****
  • Posts: 514
Re: KISM Status
« Reply #2 on: March 15, 2013, 06:26:20 PM »
Tony - Good luck on the hiss, but I think the real problem is that your receiver just has a poor squelch gate. Anything that filters that out is going to make the desired audio sound like it's going through a sock. Only solution is either modify the rig or brew up an external squelch, which would be pretty easy... one quad op-amp and a handful of resistors and caps. Could tailor some nice audio, too. Sounds to me like you have two different receivers... what's the setup?

Offline TonyP123

  • Newbie
  • *
  • Posts: 8
Re: KISM Status
« Reply #3 on: March 21, 2013, 07:23:07 PM »
The main radio is an AOR AR5000  kinda over kill for this task. I have it connected to a SCANTENNA .
One of the secondary radios I have is a Uniden 780XLT...which BTW is an excellent VHF radio but has been made obsolete on our police trunk (rebanded).

The best part of the AR5000 is its' built in filters of 5 different settings relating to the audio characteristics.I also have available the Audio De-emphasis feature. I don't use it much but did turn it on as of this recent issue I have.

 I was able to make adjustments to the I.F bandwidth. I have it set to 6kHz .  I'm not sure if I like the way it sounds.