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Author Topic: AM radio broadcast after breadboarding a lm386 and 741 op amp  (Read 4904 times)

awdman

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AM radio broadcast after breadboarding a lm386 and 741 op amp
« on: December 13, 2009, 12:38:48 AM »
alright I know it is just interferance but I was able to pick up my local AM channel 740 when I was breadboarding my LM386 project after adding a 741 chip to it. Is this normal? it is pretty cool though.

Anthony

J M Fahey

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Re: AM radio broadcast after breadboarding a lm386 and 741 op amp
« Reply #1 on: December 13, 2009, 01:05:33 AM »
On breadboards that usually are "in the open", have poor grounding and flimsy, non soldered, different metal contacts, I guess the unusual is *not* to get some interference.
Or you may live unconfortably close to said radio, in which case you will get it everywhere.
I live 1 block from the river coast in Buenos Aires, in the ancient (today only a tourist attraction) port of La Boca.
Some 10 years ago, i had that "zzzzzzzzt click click click zzzzzzzzt" sound *everywhere*, on any amp, radio, TV, Walkman, the works. (Even on the phone).
I almost got crazy, it appeared at random, lasting 10/15 minutes.
One day a sailor neighbor was visiting me and asked me "how are you picking that marine Radar?"
I went to the corner and saw this beautiful Spanish fishing ship being repaired.
It seems to be that radars have two (maybe more) settings: open sea (full power) and Port (a couple  watts or even milliwatts)
These guys were testing it full power.

joecool85

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Re: AM radio broadcast after breadboarding a lm386 and 741 op amp
« Reply #2 on: December 14, 2009, 09:20:27 AM »
On breadboards that usually are "in the open", have poor grounding and flimsy, non soldered, different metal contacts, I guess the unusual is *not* to get some interference.
Or you may live unconfortably close to said radio, in which case you will get it everywhere.
I live 1 block from the river coast in Buenos Aires, in the ancient (today only a tourist attraction) port of La Boca.
Some 10 years ago, i had that "zzzzzzzzt click click click zzzzzzzzt" sound *everywhere*, on any amp, radio, TV, Walkman, the works. (Even on the phone).
I almost got crazy, it appeared at random, lasting 10/15 minutes.
One day a sailor neighbor was visiting me and asked me "how are you picking that marine Radar?"
I went to the corner and saw this beautiful Spanish fishing ship being repaired.
It seems to be that radars have two (maybe more) settings: open sea (full power) and Port (a couple  watts or even milliwatts)
These guys were testing it full power.

Neat story.  I haven't dealt a whole lot with radio interference on than from trucker's CBs.  Here in Maine we don't have a lot of radio towers really.
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