LED / ham radio question - Fiberglass RV
RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 01-29-2021, 10:25 PM   #1
Senior Member
 
AC0GV's Avatar
 
Name: Kenneth
Trailer: Scamp
Wisconsin
Posts: 917
Registry
LED / ham radio question

I'm looking for radio operators that have solved the LED RF noise problem. I'm running Under 100 watts and receiving weak signal stuff Not the local 100,000 watt FM broadcast station..
I need an assortment of 12-volt LED lamps that are RF quiet.
I assume that that means a brand that is polarity dependent AND 12 volts only. No 12 -24 volt.
I have that now and must run an incandescent over the operating location to hear even FM repeaters.
I always turn off the converter when boondocking, but the LEDs are still jamming things. In a campground there is no hope due to other campers. I need them for the RV, a communication shelter, and a home station, all are 12-volt only systems. BTW, the Scamp reading lights are RF quiet.TNX
Attached Thumbnails
29 LED pile.jpg  
AC0GV is online now   Reply With Quote
Old 01-30-2021, 04:41 AM   #2
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 4,852
Smile Snipe hunt

It's not the LED itself that is causing the RFI issue but the bias circuitry. To eliminate brightness changes due to voltage variations, the LED's are typically powered by a switching supply, usually a current source. The switcher produces a wide band of harmonics most likely entering your receiver through one of the I.F. stages. Replacing the LED bulbs with incandescent bulbs is the simplest solution. Obviously efficiency is not an issue if you are running shore power. If you want to keep the LED's, I would try replacing the bias circuitry with a simple series resistor or perhaps a linear series regulator like the 78xx series.That would require purchasing LED's (the component) and adding your own circuitry. Note: a simple resistor bias will cure the RFI but unfortunatly your lights will now be voltage sensitive and less efficient. Most likely that's what the Scamp lights are using.

Unfortunately switching regulators are everywhere; your cell phone, your lap top, your flashlight, your tow. Even your electric toothbrush. And nothing is ever completely off.
Raz is offline   Reply With Quote
Old 01-30-2021, 07:38 AM   #3
Senior Member
 
Name: Gordon
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 4,513
Rule #1. Dont buy cheap LED bulbs (Edit: Dont buy LED bulbs with cheap voltage regulators).

Unfortunately we also need rules 2-25 to solve this problem and I have not found them yet. I've been buying from SuperbrightLEDS.com and they usually sell better quality, but the one I got from them to replace the bulb in the new style Scamp reading light was the worst RFI offender yet. Returns are easy enough with them so trial and error might be rule # 2.

I would guess that maybe two percent of the members of this forum are concerned with RFI from their light bulbs bothering their ham radios. But 100 % of the members at ARRL would have a problem with LED bulbs at home or at camp at one time or another. I assume you are a member of ARRL since it is such a good resource:

http://www.arrl.org/files/file/RFI/Light_Bulbs.pdf
ARRL :: Technical :: The ARRL RFI Book 3rd Edition
Forum » RFI - Discussion and Q&A » LED light bulbs cause RFI
Radio Frequency Interference (RFI)

(This third link is to the forum.. perhaps a post there will elicit specific vendor or bulb suggestions)
gordon2 is offline   Reply With Quote
Old 01-30-2021, 08:28 AM   #4
Senior Member
 
Larry C Hanson's Avatar
 
Name: Larry H
Trailer: Trillium
Arizona
Posts: 386
DIY LED Fixtures?

Hello,

One can build their own LED lights using LED strips from Ebay.
The strips can be cut up into 3 LED segments. Each segment
runs on 12VDC and has no active components so is very RF
quiet. Most any fixture can be converted by choosing how many
LEDs needed for the required brightness and wiring and gluing the
amount needed into the fixture. The strips work great on the old
fluorescent fixtures. In my old Trillium a couple of the original
fixtures were modified with just one little 3 LED strip piece and a
small SPST toggle switch providing ambient lighting at a cost of
70 ma. draw per fixture. Two provide plenty of ambient lighting.

Examples of Ebay Light Strip for sale:

https://www.ebay.com/itm/10pcs-50cm-...8AAOSwEzxYb0ae

https://www.ebay.com/itm/10pcs-SMD-5...UAAOSw8L5b86WF

The 'warm white' LEDs throw a nicer light than the white or cool white
because there seems to be less of the blue part of the spectrum emitted.

BTW one does not need the aluminum channel to mount the strips.
They can be glued onto the old metal fixture using JB Wed Quick epoxy.

LEDs are great but I still prefer to read using incandescent bulb using a
little AC halogen desk lamp converted to 12v by bypassing the transformer
and using a 7W landscape light type halogen bulb.

Uncle Larry
Larry C Hanson is offline   Reply With Quote
Old 01-30-2021, 09:57 AM   #5
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 4,852
Quote:
Originally Posted by gordon2 View Post
Rule #1. Dont buy cheap LED bulbs.
Actually, it's the cheap ones that use just a resistor to bias the LED. No RFI if theres no switcher.
Raz is offline   Reply With Quote
Old 01-30-2021, 10:26 AM   #6
Senior Member
 
Jon Vermilye's Avatar
 
Name: Jon
Trailer: 2017 Escape 21
Oswego, NY
Posts: 2,117
Registry
Quote:
Originally Posted by Raz View Post
Actually, it's the cheap ones that use just a resistor to bias the LED. No RFI if theres no switcher.
Agreed. While it may be difficult to find LEDs without built in voltage regulation, using them will solve the problem. They may create another one - most of the unregulated LEDs are not happy if your converter goes into equalization at 15+V. Still, the unregulated ones are cheap enough that replacing failures might make sense.

I have the same RFI problems with both my converter & solar controller when attempting to pull in distant FM stations. I've tried a number of filters, both at the devices & at the radio with no improvement.
Jon Vermilye is offline   Reply With Quote
Old 01-30-2021, 10:53 AM   #7
Senior Member
 
BatDude's Avatar
 
Name: Bat Dude
Trailer: Escape
Michigan
Posts: 343
LEDs and RF etc.

Some of the LED headlamps that are very high power/brightness have had to be set aside for our bat work. While one can see potential pit vipers while walking jungle trails the RF and sound interference has precluded virtually all ultrasonic recording of bats for a non-invasive means of surveys.


The noise swamps all sound signals below 30kHz- 35 kHz.


No longer have my HAM ticket, V31JU...never did get a US ticket when returning after 25+ years of living in the jungle.


Good luck with your quest. Most of us had to return to incandescent headlamps to not obliterate our acoustic data.



Bat Dude
__________________
Conservation biologist specializing in bats. Now stepping aside from paid $ bat work and just Escaping, painting and mentoring grad students
BatDude is offline   Reply With Quote
Old 01-30-2021, 11:18 AM   #8
Senior Member
 
Name: Darwin
Trailer: 2002 19 ft Scamp 19 ft 5th Wheel
Posts: 3,290
Send a message via Yahoo to Darwin Maring
Even the phone charger that plugs into the cigarette lighter receptacle in the car produced RF interference.
Darwin Maring is offline   Reply With Quote
Old 02-05-2021, 07:50 PM   #9
Senior Member
 
AC0GV's Avatar
 
Name: Kenneth
Trailer: Scamp
Wisconsin
Posts: 917
Registry
RF quiet LEDs

Quote:
Originally Posted by AC0GV View Post
I'm looking for radio operators that have solved the LED RF noise problem.
I ended up at Superbrightleds.com and after a long search found 2 types that were 12 volt only and a replacement for the 921 lamps, I order several of both. I found no 194 lamps that I liked. They did also have replacements for the old lamps that screw into a standard socket but are 12 volts. I wanted some for my shack project and could not find them. I'll report back about the radio noise when the WX gets warm. Highs this weekend are to be ZERO and below (f). To see my shack project, search ac0gv on QRZ.com or click on my "biography" in about me in this group.
Thanks for the leads.
AC0GV is online now   Reply With Quote
Old 02-05-2021, 08:01 PM   #10
Senior Member
 
AC0GV's Avatar
 
Name: Kenneth
Trailer: Scamp
Wisconsin
Posts: 917
Registry
RF quiet charge controller

Quote:
Originally Posted by Jon Vermilye View Post
I have the same RFI problems with both my converter & solar controller when attempting to pull in distant FM stations. I've tried a number of filters, both at the devices & at the radio with no improvement.
I just this past fall purchased TWO Bioenno Tech LLC / Bioenno Power SC-122420JUD Charge controllers. They are shipped for LiFePO batteries but there is a setting for SLA and I am using that on two sets of FLA batteries. So far, including winter field day it appears RF quiet. (mine were about $50 each.)
AC0GV is online now   Reply With Quote
Old 02-05-2021, 08:44 PM   #11
Senior Member
 
Name: JD
Trailer: Scamp 16 Modified (BIGLY)
Florida
Posts: 2,109
I bought cheap - no name - LED light fixtures and installed them all over the Scamp and have operated HF, VHF, and UHF with no issues. I have used NVIS antennas, vertical antennas and dipoles and no problems.
One field day I did have problems with a Harbor Freight inverter generator (the first 2500 watt Predator) that had hash and a EMI filter on the output took care of that.
Currently I am using an EPEVER MPPT solar controller with 300 watts of panels on the roof and have a PD battery charger/power distribution box still no problems with RFI.
Just Lucky I guess.
redbarron55 is offline   Reply With Quote
Old 02-05-2021, 08:47 PM   #12
Senior Member
 
Name: JD
Trailer: Scamp 16 Modified (BIGLY)
Florida
Posts: 2,109
"The switcher produces a wide band of harmonics most likely entering your receiver through one of the I.F. stages."
Must be very very poorly shielded IF stages.
redbarron55 is offline   Reply With Quote
Old 02-05-2021, 08:52 PM   #13
Senior Member
 
AC0GV's Avatar
 
Name: Kenneth
Trailer: Scamp
Wisconsin
Posts: 917
Registry
Roll the dice

Quote:
Originally Posted by redbarron55 View Post
I bought cheap - no name - LED light fixtures and installed them all over the Scamp and have operated HF, VHF, and UHF with no issues..
Yes, it seems to be a real roll of the dice. Some cause no trouble and others jam everything. My first house LED lights are now in an outbuilding and if I forget to turn them off they jam radios in the house. And my first charge controllers are now owned by non-hams.
AC0GV is online now   Reply With Quote
Old 02-06-2021, 06:53 AM   #14
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 4,852
Quote:
Originally Posted by redbarron55 View Post
Must be very very poorly shielded IF stages.
Yes. Better receivers are dual or triple conversion with one of the IF frequencies at 455 khz. Most switcher run between 10 khz (some you can hear!) and 100 khz, putting harmonics right there. I have seen shielding on the front end and if the radio has a power supply it will be a well shielded switcher, but not much on the IF stages. With a narrow band and mV signals, I doubt designers worry about ambient noise.
Raz is offline   Reply With Quote
Old 02-06-2021, 08:02 AM   #15
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 4,852
Quote:
Originally Posted by AC0GV View Post
I ended up at Superbrightleds.com and after a long search found 2 types that were 12 volt only and a replacement for the 921 lamps, I order several of both.
I hope this works but I think you are going to find that these too will have switching drivers. Years ago I converted an old Coleman lantern to LED's. High output LED's and a series resistor. Superbrights used to sell the LED'S. Should you need to go that route, it's not hard to do.

Click image for larger version

Name:	20210206_085149.jpeg
Views:	4
Size:	56.0 KB
ID:	139304Click image for larger version

Name:	20210206_085139.jpeg
Views:	3
Size:	36.0 KB
ID:	139305Click image for larger version

Name:	20210206_084510.jpeg
Views:	4
Size:	71.2 KB
ID:	139306Click image for larger version

Name:	20210206_085222.jpeg
Views:	4
Size:	62.1 KB
ID:	139307
Raz is offline   Reply With Quote
Reply

Tags
scamp


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Calling all ham radio people HF op in a Scamp? gordon2 Hobbies & Passions 89 12-10-2020 01:04 PM
HAM Radio in a 16' Scamp Deluxe frankcfx Problem Solving | Owners Helping Owners 6 03-16-2014 06:40 PM
Ham Radio Al POGUE Hobbies & Passions 103 10-22-2013 01:11 AM
CQ CQ Ham Radio Scampers... Bob H General Chat 4 06-15-2012 07:48 AM
Ham radio Scamp for sale on QRZ.com Mike Taylor Classified Archives 0 06-29-2009 05:47 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 10:15 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.