A 396 observation

[scanrrman]

I was laying on the couch which is right next to my computer desk. My 396 was scanning all the usual stuff I scan. It was beeping low battery and I plugged it and set it on the computer desk next to me. I began to observe the scan rate decrease dramatically!!! Instead of it only taking a second or two to scan through system qk's 1-8 (which is does pretty quickly) it was taking about 4 seconds to scan!! I watched it for a few moments w/ no signs of it getting better. After about 10 minutes of watching I moved it into my usual spot in the bedroom. To my amazement (thankfully!!!!) it began scanning very fast like normal w/ the same systems on and me not changing a thing besides the location of my scanner. What is the deal?????????????? Was it my computer putting of some kind of interference?? This is spiking my curiousity. Can anyone offer any kind of plausible explanation? Would my computer really cause my scanner to dramatically slow down in its scan rate?

[XTS3000]

You better believe computers put out all sorts of interference that can slow down scanning. I realy notice this happening with the 996T.

What is happening is your computer is putting out so much interference, that your scanner is stopping on almost every frequency because of the interference. Once the scanner determins the noise is just noise, it continues it's scan, only to stop on the next frequency. This stopping on almost every channel causeing the scan speed to come to a crawl.

Even if every frequency in the 396 has a PL or DPL tone associated with it, the scanner will stop on frequencies with noise. The scanner stops on the noise, and then determins if the PL/DPL is correct, if correct then the squelch opens - if not, on to the next frequency.

What you are experiencing with slow scan is normal when using it around anything that causes interference like computers, routers, plasma TV's and video game systems. Try turning up the squelch a few notches.

Just pull the antenna off the scanner when you notice slow scan speeds. See if the scanner speeds up like normal operation. If it speeds up, then you are around some nasty interference.

You also mentioned the issue got worse when you plugged it in to the wall. The power cable is acting as a "counter-poise". Basically giving you a better ground plane. The better your ground plane is, the better you receive. Although if your plugging in your wall-wort to the power strip your computer is plugged into, the scanner has a chance of picking up your computers swiching power supply noise through the scanners wall-wort.

Cheers

[jtsjc1]

If I have my 246 on the table next to the comp, I can hear the movement of the mouse on the scanner. Sometimes it will slow down the alpha tags also. Joe

[scanrrman]

I figured it was the computer but I wasn't sure because all my freqs have PL/DPL programmed except for the mutual aid channels. That's pretty crazy!! I'll never set my scanner near the computer again, that's for sure. I got really upset at first like something was wrong but after moving it back into the other room I was very much relieved. It kept holding on systems that only had like 4 conventional freqs in them. Thank you very much for the informative reply!!

[XTS3000]

Yep, I also have all my channels programmed with PL/DPL. I noticed this problem when I tried scanning with the 396 and 996 both next to the computer. The 996t has slightly higher sensitivity, so it picks up a bit more noise too.

I put a discriminator tap in the 996, and while scanning, you hear everything (static, interference, etc.) while scanning through my computer speakers. Even when no one is talking and the scanner is scanning, you can hear the 996 stop on almost every channel while scanning.

Thankfully computer generated noise is not that strong. My simple solution was to get a 6 foot coax jumper plug the antenna into one end and place the antenna farther away from the computer. The interference disapeared for the most part, and scanning sped up considerbly. Better yet, an outside antenna works excellent. If you can't put an antenna on the roof, the attic works almost as well.

Good luck

[PeterGV]

PC = RFI Madness.

Back in the day (of, like, MS-DOS and stuff) there was actually a funny little program you could run on your IBM PC that played the Star Spangled Banner on an AM radio that you sat next to the system.