Batboard

Hi

I have a truck with one of the large orange strobe lights on it. Went you turn on the light, you hear noise over the GM-300. There is not contact with the light except the ground plane and all the connectors are tight. More than likely it is feed back though the wiring systems. Any Ideas on how to stop this????


ADAM

What brand/model is the "Big Orange Light"? Is it old? Many of the old double flash stuff didn't have very good RFI Protection. Thats why you hear WEEEEE WEEEEEEEEEEEEEEE.... WEEEEEE WEEEEEEEEEEEEE.... WEEEEEEE WEEEEEEEEEEEEEEEEEEE the radios of vehicles with old whelen stuff. New Haven has some cars with old double flash edge bars. I swear, the power supplies make more noise than the siren.

Must be another fine Whelen product. Several blunt smacks with a hammer fixes most Whelen power supplies....hell...it even makes some of them work again!

Seriously, install a good noise filter on the radio. Also try to move the radio's power and ground source to a different location away from the strobe's power leads.

I used to hear that in radio's with older 1980's era power supplies. If its getting its power from a remote power supply of recent vintage, there should be an RFI drain off of the strobe cable that is suppose to be grounded. Check to see where the ground for the power supply is, vs the radio.

If its one of those standalone strobes, just try to relocate the ground for the strobe, or even the radio. It very rare to have the strobe noise come thru the radio these days.

(BTW: I have a total of 22 strobes in my vehicle with 3 radios, haven't heard any RFI).

nmfire10 wrote:

New Haven has some cars with old double flash edge bars. I swear, the power supplies make more noise than the siren.

You still gotta love the sound! A couple of the guys in the FD still have those older all metal p/s, and they are still classic. I believe our rescue truck still has them for the rear strobes, and when your sitting in the back....

Those things are old, loud as hell but they keep on ticking. Well, ok more like screaming, but you get the idea.

If it is an old rotator light..the problem can be fixed or reduced by cutting the power lead on the rotator motor.. wind the power lead around a ferrite ring and reconnect..do the same for the ground lead ... place a .5 to 1 uF cap across the leads (avoid electrolytic if possible, Mica or Tantalum work best) *** keep the leads on the cap as short as possible**** this should eliminate (or at least reduce the noise from the light)......Z

WE have had a numbe r of strobe lights make noise with the motorola mobiles.Maxtracs,radius , gm300.We go to the radio control head and short out yellow and black/red tracer
wires to cancel hook switch function. SQ. still works on front of
radio. We learned this first when scanning with mic off hook.
Then we found that it stopped sounding the strobe light through the mobile radio speaker.
Susan157
eMail va3srm@rac.ca

If possible, try to relocate the antenna or strobe. I have seen some work trucks where they were next to each other and caused problems.

Is the noise heard on other radios when you transmit, or is it heard on your radio (the problem radio) when you are recieving?

I have been dealing with the whelen strobes for 20+ years now. TYhe only time I've heard this noise was on a lo-bander (45mhz) receiving a distant signal. Is the radio a lo-bander? If not, then you have a problem with the strobe light itself. The oscillator used to generate the high voltage has become more wide band because of possible corrosion/ failing of buypass caps because of water/ moisture getting in on the circuit boards and is "sweeping" through some high freqs. Your radio alone may not be the only thing this strobe light is interfering with. In this case, yes , the power filter on both the light and the radio may cure the problem, but this is a pre-amble to an existing problem that may lead to your light failing. I am still not convinced of having high voltage circuits like this in the open environment.
SOMEONE PLEASE GIVE ME BACK MY SOUP CAN LIGHTS FROM THE EARLY 80'S. The power supplies were inside the car, miles of strobe cable, but never a failure.
I have alot of older power supplies from the EDGE era( circa 1980 through
1990) You could defib a patient with these babies:>:>:>:>:>:>:>:>
Jimmy

Even know they may sound good. but lost of guys like hearing the noise from the OLD Whelen P/S They just have this sound to them.

best is to take an old whelen Strobe II but a Telephone industive pickup next to it

I have the schematics for the old PIE PAN power supply, and the old WPS 222 siren. The oscillators are IDENTICAL, so you see where the idea for strobes came from, first came the siren, then came the strobe. 555 oscillators, 4013 switchers, and triacs to fire the neg. trigger. Ya gotta play with one some day. As Robinn Williams would say in his younger comedian days:
" I want yall to grab the backend of your tv set and feel the power, as it shocks you butt across the room; and it'll move ya, Move ya, MOVE YA! Somebody'll get a laugh!!!!!!!!!!
Jimmy

Medic 1 / 10 in Seattle use those loud "Weee weeeeeee" strobes. I love the way they sound...
Scott

My god!!!!!!!!!!!How old is Medic1/10?/ I service a '79 Grumman Telesquirt still using the UPS 90.

Maybe they were made in France before the US....?

Cool sound, don't fix it unless it is way too loud. I remember hearing that "wuh-whaa wuh-whaa" on the AM aircraft band and in aircraft headsets way before they were used on vehicles!

And you didn't use the gold film strobe tubes? They cut down the intensity a little, but heck that far up you can see strobes for 10 miles or so.
Jimmy