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Radio Shack sound level meter

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Kekkaishi

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radio shack special

Hello to all,

I need to design FM receiver that is able to tune to commercial FM radio broadcast channels spanning from 87.5 MHz to 108 MHz, and to produce audible demodulated output. Doing some research, I came across radio shack special. I've tried to enter the author's website but it is dead. So I need some guidance from all of you.


1. Instead of using audio jack & headphone, can I change it with speaker? If can, May I know which type of speaker can be used?

2. If I want to design the pcb board using ultiboard , may I know which component in the ultiboard's library should I use to represent the source and drain coil? Another thing, since I just learning ultiboard using e-book, what component should be used to represent antenna in the ultiboard. Sorry for this stupid question but I really need guidance from all of you.

3. For the Drain coil, may I know how to make it has 3 turn tap?

Anybody has the copy of instruction from Mr. Patrick website?

Thank you for all your helps.
 

radio shack trimmer cap

I build this radio but with BF 247 and work fine,you can also use BF 256 .
 

radioshack special

zlatkoMM said:
I build this radio but with BF 247 and work fine,you can also use BF 256 .
Click to expand...

Can you please explain more?

echo47 said:
I see several other web sites describing that little receiver. You may find some answers there:
https://www.electronics-lab.com/projects/rf/007/index.html
https://solomonsmusic.net/RadioShackSpecial.html
**broken link removed**
Click to expand...

I've tried looking at all the website mentioned but they are older version of mr patrick cambree right? Anybody else who have the guides/instructions from mr patrick's website? please...
 

trimmer capacitor radio shack

Thanks echo47. Now I can see Patrick's RSS. May I know how to make the drain coil to has 3 tap?
 

mpf102 detector

I don't think I know the full answer, but for other folks to help you, please give a link or image or something showing exactly which coil you are referring to.
 

f245c fet

Oh sorry for not showing the image. Below is the coil I've mentioned before.

23.jpg


One more thing, Instead of using audio jack, can I use speaker? And do I need capacitor or resistor to connect the speaker with lm386?
 

build drain coil fm radio

You can connect an 8 ohm speaker to the output jack. The circuit feeds the output through a DC blocking capacitor. The "radio" has an AM detector and does not have AGC so the volume from an FM station (tuned to one side) will depend on the strength of the signal. If the signal is strong and if the 9V battery is brand new then the LM386 will produce 0.45W.
 

special for radio shack

Hi Kekiashi....
Drain wire is after 2 turn for 88-108MHz.
Tuning freq also depends of tuning capacitor.
If you use standard tuning capcitor from am/fm radio
coil must have 5 turn fi-8mm Cu 1mm wire streched 13mm,drain wire also after 2 turn.When i making this i dont use IC for amplifier but ordinary npn transistor
conected to headphones.
regards
and good luck in build...
 

buy 100nf capacitor radioshack

Thanks Audioguru and zlatkoMM,

One more question, the MPF102 FET Transistor is out of stock at my area. So may I know other transistor that could replace this MPF102? Thank you.
 

how to use radio shack pcb

Kekkaishi said:
One more question, the MPF102 FET Transistor is out of stock at my area. So may I know other transistor that could replace this MPF102?
Click to expand...

One of your local suppliers should carry a brand called NTE. That company specializes in substitute parts. Their NTE451 is listed as a substitue for MPF102.
You can get the data sheet by doing a search for MPF102 from the following web page: http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm
 

radio shack special and ground plane

Thanks House_Cat. I'll try looking for that component.
 

mpf102 multisim

Also you can use BF247 or BF 256 fet .
I not suggest you build coil on board becose how can you adjust cooil if is on board?
So better build with Cu wire 0.8 to 1 mm.
Varicap with 2 plug must be good for FM.
 

mpf102 substitute

Is there any difference between varicap and varicap diode.

The one I have is like the picture below. The plastic one. Is it ok to use it for this radio shack?

**broken link removed**
 

radio shack

It is actually called a variable trimmer capacitor.
A varactor diode is a diode that changes its capacittance when you change its voltage.

Your variable trimmer capacitor is fine if its range of values is correct.
Adjust it with a plastic screwdriver to change the tuned frequency.
 

fm teil bf256

Thanks Audioguru, I'm afraid I bought the wrong one. Anyway should I use 10pF or 20pF or it doesn't matter?

Added after 26 minutes:

zlatkoMM said:
Also you can use BF247 or BF 256 fet .
I not suggest you build coil on board becose how can you adjust cooil if is on board?
So better build with Cu wire 0.8 to 1 mm.
Varicap with 2 plug must be good for FM.
Click to expand...

Oh, what I mean is I need to design PCB board using Electronic Workbench Multisim and Ultiboard Software. So there's no component in the library for the coil and I need to make it one. Therefore I need the width of the coil. I think I need to construct the coil first and then measure the size so that I will have the measurement for the coil and it will suit in the PCB board. Thank you for your help.
 

the radio shack special project

I tried finding enamel coated wire but it is too hard to find in my local store. Is there any other wire that I can use to replace enamel-coated wire? Can I use normal jumper wire? I just wondering, why we need to use coil and not inductor?


**broken link removed**

Refer to the schematic above, If .1uF capacitor is electrolytic capacitor, the +ve polarity should be to the .0047uF or the potentiometer?
 

radioshack in croatia

I have some speakers with a woofer and a tweeter. There is a crossover network that directs the low frequencies to the woofer and the high frequencies to the tweeter. The crossover network has three inductors that have enamelled wire. Each inductor has many turns of the wire and don't even notice that I stole a little to make the coils in my FM transmitter.

I have a box full of wall-wart AC to DC adapters. Each one has a transformer with enamelled wire.

The FET transistor is positive and the volume control is grounded. Use a 0.1uF (100nF) metalized plastic film capacitor, not an electrolytic. If you use an electrolytic then the positive wire goes to the positive FET transistor.
 

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