KSBP Up and Running

[SLO_Mike]

The feed has been up and running for a couple days but finally approved by liveatc today.  Here are a couple pics...  We have homemade j-pole, scanner and taplop in the closet, and the tower on departure.

 

[dave]

Nice job guy...feed sounds great!  One of the best.

Dave

[Jacko]

I am listening to this feed now and there seems to be constant ground hum

[SLO_Mike]

I am listening to this feed now and there seems to be constant ground hum

I noticed the same thing if the volume is turned up really loud.  I don't notice it at normal listening volume.

I tried connecting the laptop chassis gnd to my scanner antenna gnd but it didn't help... actually made it slightly worse.  The scanner and computer grounds should already be at the same potential via the audio cable.

I attributed the hum to the really long (8 footer is all I had laying around) 1/8" jack to 1/8" jack audio cable I am using and the fact that there is a cable modem and wireless router in the same closet.  I have not tried a shorter cable yet.

Any other ideas?

 

[dave]

I am listening to this feed now and there seems to be constant ground hum

Turn your volume down a bit - many feeds occasionally have ground hum but it is not always possible or easy to eliminate.  An audio isolation transformer between the scanner and sound card input is the best way to fix this when grounding doesn't work.  However, you need to be careful about impedance matching so that you maintain a reasonable audio level into the sound card.

-dave

[SLO_Mike]

I am having trouble with volume control.  I originally had this feed setup on my VXA-710 aviation handheld.  I had the volume on the first click on the radio and the "mic volume" in the volume control on the laptop just off zero and was still over driving the input.  The audio quality suffered due to the clipping.

Now I using a RadioHut TrunkTracker scanner with the volume maybe set to two, computer is still the same so I really can't turn it down much more.  I am thinking about adding an attenuator (voltage divider) in line so I can get some resolution out of the volume controls.

I might head over to RadioHut to pick this up...

http://www.radioshack.com/sm-buy-the-ground-loop-isolator-on-http-wwwradioshackcom--pi-2062214.html

 

[Jacko]

May I also suggest, keep your audio lines well away from power leads, as these can interfere, use shielded cables from the scanner to that lappy as well.

Also keep cables nice and short, and dont use the mic port on your soundcard use the line in port.

With my I used balanced cables in my audio setup although they are not very cheap..

[SLO_Mike]

May I also suggest, keep your audio lines well away from power leads, as these can interfere, use shielded cables from the scanner to that lappy as well.

Also keep cables nice and short, and dont use the mic port on your soundcard use the line in port.

With my I used balanced cables in my audio setup although they are not very cheap..

Thanks for the advice but the old taplop I am using doesn't have a line in... only a mic jack.  I am going to try the isolation transformer later this week and go from there.

 

[kobe6377]

   pretty

[SLO_Mike]

I might head over to RadioHut to pick this up...

http://www.radioshack.com/sm-buy-the-ground-loop-isolator-on-http-wwwradioshackcom--pi-2062214.html

Picked up the audio isolation transformer this afternoon from RS but it didn't change the hum at all.  I don't think the hum is from a ground loop anymore.  I am thinking it is the mic input on the taplop.  I don't have a line in so I think we are just going to have to live with it.

 

[Squawk 7700]

Sounds great on my end. I do hear a slight hum if I crank up the volume, but it's not that noticable.

[SLO_Mike]

Sounds great on my end. I do hear a slight hum if I crank up the volume, but it's not that noticable.

I installed a new soundcard yesterday that has a line in instead of using the laptop's built in mic in jack.  I think the feed sounds better with less hum.  Let me know what you guys think.