Cheap LED radio inteferrence?

[Roger Long]

Picking up on "Four Points" idea of using a cheap solar walkway light to light up a Windex without running wires up the mast, I picked up a Hampton Bay unit for under 4 bucks at Home Depot. It's light, and easily reconfigurable. The LED is mounted on long leads so easy to snip, solder and relocate.

I'm just about to start the project but I have a thought. I've heard of LED's causing interference on VHF frequencies. Will having this thing 6" from my antenna cause problems?

I'm going to go dig my handheld radios out of my storage unit tomorrow and experiment but I'd be interested to know what our resident radio experts think. It wouldn't surprise me a bit to find no problems with the handheld's and then get this thing up on my mast and out of reach and discover that I have a problem. Radio is witchcraft to me.

 

[woodster]

Radio is witchcraft to me.

you think thats bad i had a friend buy a radio one time advertised and the smallest radio in the world................. it worked fine for about six months................he turned the dang thing off.............. and hasnt be able to find it sence

regards

woody

 

[Maine Sail]

Your biggest problem with be finding a voltage controller to supply the right amount of voltage to the light so you don't kill it, and yes you may likely have radio noise issues if you add a voltage controller .

Here's a good discussion on why the right power supply is critical.
http://store.marinebeam.com/whyounetokna.html

 

[Mark Maulden]

find a power boater so you have access to an antenna/radio. Handhelds could be less sensitive. Put ur light next to antenna in all orientations and up/down the antenna. Try 4-5 channels. If no interference, then ur probably OK. Usually, it's wiring that radiates so ur chances are good.

 

[kenn]

Picking up on "Four Points" idea of using a cheap solar walkway light to light up a Windex without running wires up the mast, I picked up a Hampton Bay unit for under 4 bucks at Home Depot. It's light, and easily reconfigurable. The LED is mounted on long leads so easy to snip, solder and relocate.

I'm just about to start the project but I have a thought. I've heard of LED's causing interference on VHF frequencies. Will having this thing 6" from my antenna cause problems?

LEDs themselves don't create interference; any interference will come from high-frequency switching-type regulation used to limit current to the LED(s)

I wouldn't expect that cheap solar-charged walkway lights would employ high-frequency regulators, but I don't know for sure. I have a couple in the basement, I should haul them out and crack one open...

In any event it's fairly easy to test for RF radiation. You can do initial tests with a cheap AM-FM portable. Trying both AM and FM bands - tune to a quiet spot between stations, turn up the volume and move the radio toward and away from the light and listen for a buzz/whistle/whine when you're close.

A handheld VHF should be sensitive enough to detect any significant VHF-specific noise, especially since you can get right up close while testing.

With FM and the VHF units, make sure that any muting or squelch is off and you're hearing that lovely annoying rushing sound, in order to test.

One other point - I believe that masthead antennae are most sensitive to the side, and least sensitive directly above and below the antenna, so that could work to further minimize interference.


But whoa! A lawn solar unit as windex light is a cool idea! :dance: I hafta consider this while my mast is down. One could possibly change the whitish LED for one or two red ones; they might work better with the red reflectors and be kinder to your night vision.

 

[Roger Long]

I have a couple in the basement, I should haul them out and crack one open...

This is the one I'm thinking of using:

Do you see anything that looks like a high frequency switching power supply there?

 

[JohnShannon]

I see no evidence of a high frequency regulator (an inductor) this looks like a linear regulator and should cause no RF problem

 

[Bill Roosa]

I agree, no HF circuits here so there should be no problems. I have 60+ LEDs on my courtesy light which runs on straight DC and I don't have a hint of interference.

 

[Forrest15112]

I wouldn't be concerned about the interference. I have worked with RF for 25 years and never had a problem with nearby solar panels nor dc-dc regulators. I don't recall any cases with something at the antenna either but simple DC to DC regulators don't switch or even filter much ripple out of the solar panel. The solar panel will not be generating anything at night anyway ( unless you get those new lunar panels) . A battery powered LED will generate no RF noise.

This is really a cool idea. The only possible problem I see is cheap yard LED's come with cheap batteries. You might consider a better quality battery. I was thinking that a couple of low intensity red LED's on the stationary markers of the windex facing downward would be easy to see. You still have the issue of seeing the vane though.

My boat has been on the trailer for a few years and I have been getting it ready for the water. I am already replacing mast lines, wiring, etc. This is definitely something I will look into because I do most of my sailing at sunset/ night time and have kept a flashlight in the cockpit mainly to check the windex. I wonder if these types of lights could be confused with standard marker lights? Thanks for the idea.

 

[Alex Dare]

Keep in mind, most of the older FM VHF transceivers..marine, ham, aviation..ect.. not to mention the old CB radios (AM) had LED displays and indicator lights built right into them. I'm sure you'll be fine.
I think you could probably pot that PCB in some epoxy or soemthing similar and give yourself some extra weather protection.

 

[Roger Long]

You still have the issue of seeing the vane though.

I think just an LED at the base of the vane shaft should be sufficient. It doesn't take much once your night vision kicks in and the Windex has a reflector on the tail. I don't plan to install the windward angle markers on my Windex. I think they are silly and, besides, they would just depress me about the less than stellar pointing ability of Strider[/].

It should be a dark night tonight so I'll take the unit and Windex outside and assess.

Good idea on the battery.

 

[FourPoints]

I was waiting until I got all the pictures posted, but I went ahead and posted what I've got since this thread took off a little sooner than I expected...

http://sailingit.com/blog/archives/176

As for the concern about interference, this unit operates on 1.5v DC, I don't think there are any interference concerns.

 

[Roger Long]

I went ahead and posted what I've got

You're doing better than I am. I unsoldered the LED from the circuit board and soldered in a few inches of wire so I could move the LED away from the unit. Now, neither the LED nor the circuit board work.

Are LED's very temperature sensitive?

I've done this kind of thing before and didn't have any problems playing Dr. Frankenstein with the solar light to power the air pump but something went wrong here.

 

[FourPoints]

I got the pics of the light installed uploaded to the site and added to the bottom of the page, still haven't found pics of the internal components or the epoxy bedding and zip tie installation.

http://sailingit.com/blog/archives/176

as for LEDs being temperature sensitive, they are (somewhat), but a soldering job probably wouldn't hurt them, but too much heat on the board could have damaged something. LED's are also polarity specific and only operate with the positive and negative correct, unlike a traditional incandescent bulb which doesn't matter. Try flipping the wires to reverse the polarity and see if that helps.

If the bulb leads are short as in many of the models I looked at, you may be better off buying one with a longer lead to work with so you don't have to touch the PCB... The one I got was only $2, so you can afford to buy a few and mess up once or twice

 

[kpgraci]

Are LED's very temperature sensitive?

If there is room to attach it I use an alligator clip as a heat sink between the solder joint and the part/circuit. To be extra safe you can have a bit of damp (not wet) paper towel clamped around the wire.

 

[FourPoints]

Your biggest problem with be finding a voltage controller to supply the right amount of voltage to the light so you don't kill it, and yes you may likely have radio noise issues if you add a voltage controller .

Here's a good discussion on why the right power supply is critical.
http://store.marinebeam.com/whyounetokna.html

That's not a problem with this setup, it's already built in as a complete unit...

 

[Maine Sail]

That's not a problem with this setup, it's already built in as a complete unit...

A lot of the home units are designed to run on 12V only not 14.4 +/-.. If you remove the 110V regulator you may be left with a device that is not adequately built for 12+ volts and it may have short life.. I can't tell by looking at that device but do know that the PC board looks different than marine/automotive LED units I've seen and used. If you've used it and it works then that's good info.

 

[Witzend]

A simple voltage limiting circuit deploying a zener diode will protect your LED from charging over voltage, no need for a fancy PWM control.

 

[Roger Long]

I can't tell by looking at that device but do know that the PC board looks different than marine/automotive LED units I've seen and used.

I can hazard a guess by buying the whole gubbins at Home Depot for less than 4 bucks that is not at all marine or even automotive quality. It might be to aviation standards, (just a wry gibe from a former G.A. aviation maintenance officer, you wouldn't believe the junk that gets put in small aircraft because the FAA makes it impossible to upgrade anything.).

Since it's sole source of power is a little solar cell and a single 1.5 volt battery, I don't expect it to get overpowered.

 

[kloudie1]

You are correct, Roger.. ya won't have any trouble with radio interference from that thing. I have been using one for a cockpit light/additional anchor light for a while.. I've not had any problem with the hand held close to it. Mine was $2.99 at the wallyWoild .. I did put in an Energizer 2450 milliampere-hour nickle metal hydride batt in place of the original cheapie.. Runs all night on a charge..