laptop power supply interference

[blueangel-eric]

I have a older Dell Latitude laptop and the power supply puts out terrible interference on VHF and makes 2m and railroad listening impossible in my apt and when mobile. Yes i take the Laptop with me. I have a ferrite bead from a old pc power supply on it with the wire looped through it a few times and then also tried a few radio shack clip on beads on both cables and doesn't reall help much. don't know what else to do. if there isn't any internal mods to do would those aftermarket power supplies walmart now sells be any better?

 

[datainmotion]

Eric,

My experience with the Latitude and Inspiron series is that the noise is generated internally (possibly the charging circuit in the laptop).

Mike

 

[blueangel-eric]

The signal strength meter shows a strong signal coming off the power supply full strength but not the computer. when i unplug the ac cord then the noise goes away.
It's a Latitude D600 btw.

Eric,

My experience with the Latitude and Inspiron series is that the noise is generated internally (possibly the charging circuit in the laptop).

Mike

 

[datainmotion]

The charging / power supply circuit inside many consumer-grade laptops is a common point of failure (yours may be "telegraphing" that)

When you use it "mobile", do you use an inverter or an actual DC power supply that plugs directly into the laptop?

Back to the AC power supply though, is there a friend or relative who uses a Dell Latitude or Inspiron laptop you could use for a couple minutes to determine if its the power supply or laptop?

 

[blueangel-eric]

The charging / power supply circuit inside many consumer-grade laptops is a common point of failure (yours may be "telegraphing" that)

When you use it "mobile", do you use an inverter or an actual DC power supply that plugs directly into the laptop?

Back to the AC power supply though, is there a friend or relative who uses a Dell Latitude or Inspiron laptop you could use for a couple minutes to determine if its the power supply or laptop?

What do you mean about a common point of failure? does that mean my power supply is going bad or the computer is?

i know someone with a newer Dell with vista. would that work?

I use an inverter. the $18 Black N Decker from Walmart

 

[datainmotion]

Here's what I would to (process of elimination):

• Try a different (OEM) power supply (OS doesn't matter, voltage and connector polarity does)
• Try your power supply on a different Dell Latitude (if compatible)
• Try your power supply at a different location (someone else's house)

As for my comment on the charging circuit, it MAY be going bad, but you won't know until you try a different OEM power supply or laptop and even then, you may still not know.

 

[04Z1V6]

I had the same problem but the noise was back feeding into the 120v outlet, onto other equipment plugged into it. I solved this by getting a real good surge protector that also had RF filters.

 

[blueangel-eric]

well i tried my friends computer and swapped PS's back and forth and the newer computer is just as noisy as the old one. my old Comcrap (compaq) laptops i had were lousy computers but were easy on the RF. I guess Dell uses cheap ps designs and don't keep RF in mind. I wonder if all us radio people should write letters to Dell so they can improve things in the future or even offer better replacements for existing computers. surely we can add a choke or ferrite bead inside it and cut if off at the heart of the problem of someone knew what they were doing. I wonder what the problem could be and how to fix it. where's the power supply mods people? I know there are hams that know these things surely someone can nail it on the head.

 

[poltergeisty]

It's more than likely the Proc. Move it to a different location.

Is the adapter plugged into a grounded outlet? I just moved some things here and grounded my IBAR surge suppressor. That made a difference! In fact, I have a question to post about it though. :lol:

Try this experiment. Unplug the laptop and leave the adapter. See the same interference? Although, that might be flawed because there needs to be a draw on the line, I don't know...

 

[DPD1]

well i tried my friends computer and swapped PS's back and forth and the newer computer is just as noisy as the old one. my old Comcrap (compaq) laptops i had were lousy computers but were easy on the RF. I guess Dell uses cheap ps designs and don't keep RF in mind. I wonder if all us radio people should write letters to Dell so they can improve things in the future or even offer better replacements for existing computers. surely we can add a choke or ferrite bead inside it and cut if off at the heart of the problem of someone knew what they were doing. I wonder what the problem could be and how to fix it. where's the power supply mods people? I know there are hams that know these things surely someone can nail it on the head.

Chokes won't fix it... Unfortunately it's more than that. It's basically just low cost components. All this kind of stuff is manufactured en-masse by huge factories in China now. It doesn't matter what brand you buy, chances are the sub components came from the same place, or even the same factory. People want cheap prices, so that's what we get.

Try looking for a power supply with the same specs, only better quality. Just be careful it's exactly the same and has the same polarity plug and all that. I'm hesitant to suggest it, because I absolutely do not want to be responsible for somebody burning their house down. But you can take some kind of metal box and just hold it up against the wall over the power supply. Or if it's on the floor, set it over it. DO NOT leave it on there for more than a minute just to test and DO NOT let the metal come in contact with the supply. See if that slows it down or stops it. If it does, you might be able to make something out of brass mesh that will pass heat and block it some. But do not restrict the heat at all or come anywhere near touching the power supply. This is at your own risk.

 

[blueangel-eric]

It's more than likely the Proc. Move it to a different location.

Is the adapter plugged into a grounded outlet? I just moved some things here and grounded my IBAR surge suppressor. That made a difference! In fact, I have a question to post about it though. :lol:

Try this experiment. Unplug the laptop and leave the adapter. See the same interference? Although, that might be flawed because there needs to be a draw on the line, I don't know...

I'm in a small apartment. no where to move the computer and be far from the antennas. this outlet is one of the few that is grounded. i checked with an electricians tool that you plug in and it lights up. The living room has a wireless router with lots of noise and the laptop sits at the kitchen table. I was going to move it to the living room but i now use it for ATCS monitoring so i need it in there to reach the 900mhz mag mount antenna on the pizza pan sticking out the window.

 

[blueangel-eric]

I used some metal casing already from a CB radio to block the signal and that didn't work at all. I put it all around the PS and it didn't affect it at all. it's unbelievable. nothing stops it. Of course it didn't cover it perfectly on all four sides but you'd think it would cut it down some.

Chokes won't fix it... Unfortunately it's more than that. It's basically just low cost components. All this kind of stuff is manufactured en-masse by huge factories in China now. It doesn't matter what brand you buy, chances are the sub components came from the same place, or even the same factory. People want cheap prices, so that's what we get.

Try looking for a power supply with the same specs, only better quality. Just be careful it's exactly the same and has the same polarity plug and all that. I'm hesitant to suggest it, because I absolutely do not want to be responsible for somebody burning their house down. But you can take some kind of metal box and just hold it up against the wall over the power supply. Or if it's on the floor, set it over it. DO NOT leave it on there for more than a minute just to test and DO NOT let the metal come in contact with the supply. See if that slows it down or stops it. If it does, you might be able to make something out of brass mesh that will pass heat and block it some. But do not restrict the heat at all or come anywhere near touching the power supply. This is at your own risk.

 

[W6KRU]

I have a Latitude D600 and I don't have any issues with interference from the laptop or the power supply.

 

[blueangel-eric]

tonight the interference decided to follow me portable trackside when i was using it while watching trains with just the batteries i had to be 10-15 ft away with my ht just to scan without interference. I guess the interference is stronger with the power supply. I toted everything on my bicycle since it was cooler. I use the computer for ATCS to see the signals to know if trains are coming or not. but need to be able to listen to the trains too without the same tool being my worst enemy. and someone said put the computer further away from the antennas well in the car that dont' work too well

 

[poltergeisty]

Maybe the rejection in your radio is craptacular?

 

[smason]

I have 2 Dell D810s a Dell D800 and a few others (same supply as the D600) and I've never noticed an issue.

 

[blueangel-eric]

It's an FT60R i have the most problems with and that's the only dual band with multiband receive i have. though other radios do have problems. just not as bad. but then this one covers more freqs that the others don't cover. more freqs = more interference.
someday when i have more money after i get a new bicycle and other stuff i will have to get a different model radio i guess.

Maybe the rejection in your radio is craptacular?