Improving AM radio reception?

[ultrarunner]

We had medical equipment that required isolated ground... and special outlets so marked... it was to cut down on the "Noise" if I remember correctly...

 

[Bendboater]

any quick and easy way to filter the AC voltage?

Probably not. It should have been done in the radio power supply and you would really need to know the frequency of the interference to try to target it.
BUT, perhaps you could mess with the external DC power supply to the radio? In the case of my CCrane radio, there is a "wall wart" (DC power supply) that plugs into a wall outlet and has a power cord (zip cord) coming out of it that plugs into a 6 Volt DC input jack on the radio.
Option 1 - changing the power cord position (move it around....try coiling and/or twisting it if possible) might help ....... some. Maybe even wrapping some aluminum foil around this cord will help....some.
Option 2 - Put ferrite beads on the power cord, real close to the plug that goes into the radio (Google "Ferrite Snap on Rings RFI/EMI Noise Filter") I see Amazon has a package of them for about $10 ..... way over priced, but super easy to order.
Option 3 - Power the radio with a 6 volt lantern battery (or even a lead acid golf cart battery that can be occasionally charged) plugged into this power jack.
Option 4 - Buy (or build) a better power supply than the wall wart supplied with the radio.
I suspect that a combination of options 1 and 2 will get you "most of the way" there. Option 3 should be close to purrrrfect or a really expensive power supply in option 4

In the case of the other radio with the built in power supply?????? Maybe you could put ferrite beads on output of the built in power supply, but this would be a more challenging task (if it is even possible) and you need to be careful to not do it while the unit is plugged in.....just in case you goof and grab the wrong leadsullinghair:

Hope this helps.

 

[tallyho8]

Strikes me you just might be North of Line A out there, and de radio itself might not be de problem. Whole bunch of stations North of Line A was required to downpower transmission year or so back which meant lousey signal in lot of places.

(removed), I'm glad to see you posting again. I've missed most of your latest posts but back in 2013 before you stopped posting for a few years you had some very entertaining stories and I advise anyone who has a little spare time to read some of your old posts for some award winning swamp humor. :thumbsup:

 

[dragoneggs]

No wall warts for either radio. Just straight 110v into the back of each. In fact their plugs are interchangeable.

 

[user.69169]

What time of day you noticin de radio takes a dump? All day you added sumtin wid a switched power supply causin de noise. Could be dem new LED lights.
Got a HAM car headlight I wiggled a LED cob into few weeks back cause I could, and running on battery no RF interference. Running on LED power unit makes de radio go nuts. Switch plugs so dey on opposite sides of de phase to Neutral an radio goes back to bein happy.

Radio craps out after around sundown I stickin wid de line A thing.

Listen real careful when station IDs, lot of stations now announcing second call sign for de auxiliary fill in transmitters used to compensate fer Line A power down.
WHAM in Rochester 50kw station on clear chanel clear as a bell for years and reached few hundred miles gotta downpower now to keep somebody happy sounds like CB set now beginnin half hour to sundown. Also announcing WAIO fill station to de South. Signal 15 miles North stinks.

 

[user.69169]

(removed), I'm glad to see you posting again. I've missed most of your latest posts but back in 2013 before you stopped posting for a few years you had some very entertaining stories and I advise anyone who has a little spare time to read some of your old posts for some award winning swamp humor. :thumbsup:

Back den I got my fill of some CENSOR fellow here who an Anti Coonazz Bigot.
Got about accomplishin other things, a man wid 9 girl Harem can have his hands pretty full, say nuthin of his job box. Good part is generally population is missin a couple who off doin whatever dey do.

Got hooked on dese pills make my blood thin too to make de clown think he half de Doctor Granny Clampet was, an dey slowin me, puttin a tarnish on my Golden Years so to say. True to tell, old age not for cowardly men wid weak spines. I got bunch of in de house jobs in line for winter, and most de Harem knows way to my house. Gotta figure out how to hook my fancy phone to a TV I don't watch so I ain't gotta grab my readers to see dat miniscreen. Mans work is never done.

 

[Bendboater]

No wall warts for either radio. Just straight 110v into the back of each. In fact their plugs are interchangeable.

OK.
Here are some more options then:
- Improve filtering in the radio power supply
- As (removed) said, find and fix the source of interference
- Google "EMI Line Filter" for some filters that may help. Most require hard wiring in, but you can probably do that in a (grounded) metal box or, better yet, inside the radio.

 

[k0ua]

Step one on ANY suspected interference issue is to run the radio off of batteries and then pull the main breaker to the house. Shut it all down. Then you will know if the interference is in your own house. Rejoice if it is in your own house, because then it is something you can do something about. Then flip on the main breaker, but power down all of the other breakers. While listening to the battery radio, flip on the other breakers one at a time. When the interference re-appears, then you have isolated the circuit where the interference maker lives. Look on the breaker box legend or go around the house to figure out what that circuit powers, and begin unplugging one at a time each appliance or lightbulbs on that circuit. Of course it could be more than one circuit breaker or more than one appliance or more than one lighting device, but you get the idea. Narrow it down. Obviously if the problem persist after you have thrown the main breaker, then that is bad news. It is likely NOT in your home. Now comes the onerous task of figuring out WHICH nearby neighbor is the problem. Or is it utility related? All of these problems are not easily solved.

 

[Industrial Toys]

Just met up with a freind that does electrical distribution. Got four (I specified RF quiet) T8 Ballasts. Apparently that is not even talked about or requested in that industry, and they are a HUGE lighting distributer. He says I bought these before and was happey with them. I asked who buys these more expensive ballasts. He said School boards and hospitals. I asked why. Because they are INSTANT start. Instant as opposed to a fraction of a second later? Obviously there is more to it.

I will test them prior to installation. Since I may use them with LED retrofit T-8s, I wonder if those make any noise. That would be kind of futile.

 

[Bendboater]

Step one on ANY suspected interference issue is to run the radio off of batteries and then pull the main breaker to the house. Shut it all down. Then you will know if the interference is in your own house. Rejoice if it is in your own house, because then it is something you can do something about. Then flip on the main breaker, but power down all of the other breakers. While listening to the battery radio, flip on the other breakers one at a time. When the interference re-appears, then you have isolated the circuit where the interference maker lives. Look on the breaker box legend or go around the house to figure out what that circuit powers, and begin unplugging one at a time each appliance or lightbulbs on that circuit. Of course it could be more than one circuit breaker or more than one appliance or more than one lighting device, but you get the idea. Narrow it down. Obviously if the problem persist after you have thrown the main breaker, then that is bad news. It is likely NOT in your home. Now comes the onerous task of figuring out WHICH nearby neighbor is the problem. Or is it utility related? All of these problems are not easily solved.

Good advice.

 

[ponytug]

any quick and easy way to filter the AC voltage?

There are some things you can to do filter AC noise, but it depends a little on what you are chasing.
You can get EMI filters like this one, or this one, but the thing about RF noise is that much of it can be/is transmitted through the air.

The fact that the OP's 2.4GHz WiFi doesn't work and his 5GHz does is further evidence of a local source of RF noise. 5GHz will always be more resistant to noise, so one might want to think about a WiFi 5GHz repeater or mesh router for the shop, and not go chasing RF noise, which can get crazy. Trust me, been there, done that.

But if you do want to chase RF noise, and since there seems to be good evidence to think that the RF noise is in the shop, I think that the idea of turning all the breakers off and turning them on one by one is a great way to narrow the problem.

As it is a shop, I would point out that VFD are huge, and I mean HUGE, sources of RF noise. Fluorescent ballasts are notorious for noise as are small motors, e.g. fans or old refrigerators. Look for dimmer switches (speed controllers) and chargers as well. Also, I might want to double check that the shop ground is actually attached (it happens), and is making good contact.

Finally, hospital "isolated" outlets (orange faced) have grounds that are isolated, i.e. run separately back to the ground bus, not to be confused with redundant grounds, which have multiple paths to ground (for patient safety). NEC Code has shifted on this toward redundant grounds, in part because the standards on patient equipment are so much more stringent than they used to be in terms of shielding and isolation. Grounding gets really complicated really quickly in my experience.

All the best,

Peter

 

[ultrarunner]

Thanks Peter... 1995 hospital addition filled with Orange Isolated Ground Green Dot Hospital Spec... have not seen similar in the area...

 

[dragoneggs]

There are some things you can to do filter AC noise, but it depends a little on what you are chasing.
You can get EMI filters like this one, or this one, but the thing about RF noise is that much of it can be/is transmitted through the air.

The fact that the OP's 2.4GHz WiFi doesn't work and his 5GHz does is further evidence of a local source of RF noise. 5GHz will always be more resistant to noise, so one might want to think about a WiFi 5GHz repeater or mesh router for the shop, and not go chasing RF noise, which can get crazy. Trust me, been there, done that.

But if you do want to chase RF noise, and since there seems to be good evidence to think that the RF noise is in the shop, I think that the idea of turning all the breakers off and turning them on one by one is a great way to narrow the problem.

As it is a shop, I would point out that VFD are huge, and I mean HUGE, sources of RF noise. Fluorescent ballasts are notorious for noise as are small motors, e.g. fans or old refrigerators. Look for dimmer switches (speed controllers) and chargers as well. Also, I might want to double check that the shop ground is actually attached (it happens), and is making good contact.

Finally, hospital "isolated" outlets (orange faced) have grounds that are isolated, i.e. run separately back to the ground bus, not to be confused with redundant grounds, which have multiple paths to ground (for patient safety). NEC Code has shifted on this toward redundant grounds, in part because the standards on patient equipment are so much more stringent than they used to be in terms of shielding and isolation. Grounding gets really complicated really quickly in my experience.

All the best,

Peter

Just to clarify... I wasn't able to sync my extender at 2.4 but it did sync up at 5 during the initial setup. This was done very close to the router. Then I moved the extender first to the shop... that didn't work so I then put in the house but as close to the shop as possible.

I should probably try to reset the extender and start from scratch to try to get both the 2.4 extender network up as well as the 5.0 extender network.

 

[ponytug]

Just to clarify... I wasn't able to sync my extender at 2.4 but it did sync up at 5 during the initial setup. This was done very close to the router. Then I moved the extender first to the shop... that didn't work so I then put in the house but as close to the shop as possible.

I should probably try to reset the extender and start from scratch to try to get both the 2.4 extender network up as well as the 5.0 extender network.

I'm sorry that I didn't understand that. That's a bit weird. I wonder whether you have WiFi interference in the main house? Microwave? Dimmers? Cordless phones? FWIW: Different routers and extenders have wildly different ranges, but if you don't need the range, no point in spending the big bucks.

All the best,

Peter

 

[ponytug]

Thanks Peter... 1995 hospital addition filled with Orange Isolated Ground Green Dot Hospital Spec... have not seen similar in the area...

FWIW: Some of the newer outlets are white with a tiny orange triangle... Perhaps so as not to be confused with red standby power outlets?

 

[dragoneggs]

I'm sorry that I didn't understand that. That's a bit weird. I wonder whether you have WiFi interference in the main house? Microwave? Dimmers? Cordless phones? FWIW: Different routers and extenders have wildly different ranges, but if you don't need the range, no point in spending the big bucks.

All the best,

Peter

Thanks Peter... yeah I got all kinds of sources for possible EM interference! In my home office where the router resides and also in my shop. Oh and AV gear in between. :confused2:

 

[DaveMueller]

2. Also tried running the CC3 on 4 D cells instead of 110v and connected the loop antenna and BINGO... with a little adjustment of radio and antenna orientations, I am getting a fairly clean reception. Not crazy about running on batteries but that's what I will have to live with if I am not using internet radio.

Sorry to jump in late, but you could probably use an old 5V phone charger. Cut the end off and put on alligator clips, then connect it to the + and - battery terminals. Be careful with polarity. 5V is close enough to 4 partially depleted D cells. Look for a brand name charger, they're usually more concerned with EMI/RFI regulatory requirements. One of the reason the Apple chargers are still $30...

Dave
(another ham AA3EE)

 

[Fuddy1952]

Sorry to jump in late, but you could probably use an old 5V phone charger. Cut the end off and put on alligator clips, then connect it to the + and - battery terminals. Be careful with polarity. 5V is close enough to 4 partially depleted D cells. Look for a brand name charger, they're usually more concerned with EMI/RFI regulatory requirements. One of the reason the Apple chargers are still $30...

Dave
(another ham AA3EE)

Good idea and kill 2 birds with one stone! The 5 volt supply, a neg. & a pos. lead. Add a diode in series with +pos. lead, anode in from supply, band end (cathode) out to radio. Something like NTE125 or similar, silicon, it will ensure polarity is correct and drop about 0.7v, (so about 4.3v).