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trouble shoot static on radio

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dksucharda

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Not sure if this is an appropriate question for this forum but here it goes. New to electronics. Just built an Elenco FM scanning radio. Ovrerall build went well. When I finished and turned it on all was well. Wen I hit the scan button it did lock on a channel and I could hear music but there as a TON of static. it is like this on every channel. I played with separation of the copper coils (the fractor?) which changes the frequency hertz the radio range the radio scans. I am sure it could be a ton of things but any thoughts/ideas would be appreciated. Thank you.
 
The TDA7088 IC circuit in an Elenco FM radio kit is junk. I think the Philips old TDA7088 IC is not made anymore, Maybe only Chinese copies.

Years ago I bought a tiny FM radio using the same circuit for $1.00 at The Dollar Store. It produced interference and did not pickup any fairly distant stations. It picked up a few local stations at the same time.
A REAL FM radio does not pickup interference and does not play more than one station at the same time.
 
Is there one of this at your place or neighbor ?
1690308459045.png

Try your receiver very far from 'civilization'
 
Start at the speaker, take scope readings of the static then work backwards through the circuit to see if you can learn where static originates from.
 
Turn off all power in house (assuming radio is battery operated) , then start breaker by breaker
turning back on. Fluorescent lights as Externet mentioned, ethernet cables, light dimmers,
generate large amounts of RF noise.

If radio line operated conder a line filter :

CW4L2-20A-S​



The above does not have filter freq response in its data sheet, so not sure how effective it is.

Build one :



Regards, Dana.,
 
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The simplest thing you could try is a longer antenna, and to "gound" not your antenna but the "ground" (negative/minus of the battery connection point to the circuit). The antenna should also not be a very thin wire.
Good luck.
 
It's a bad design using a cheap (bad) chip. Don't waste your time trying to reduce static by a few percent - static will still be terrible. The project is intended to teach you how to follow assembly instructions, read schematics and solder - it was not designed to be used on a daily basis.
 
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