/diy/ - Do It Yourself » Thread #891693

[18 / 5 / ?]

1MiB, 2448x3264, IMG_20151022_170310.jpg

fm transmitters

Anonymous Thu 22 Oct 2015 08:00:57 No.891693 View Reply Report Delete

Quoted By: >>891698 >>891965

Hey /diy/, has anyone here made a fm transmitter? And how did it work out?. I had made this one today but had no luck in reception, it's so frustrating!!, any help appreciated.

Anonymous

Anonymous Thu 22 Oct 2015 08:11:45 No.891697 Report Delete

Quoted By: >>891700 >>891702

not sure if trolling...

you cant build an FM circuit on breadboard coz it has lots of stray capacitance. secondly, these circuits are usually quite shitty coz they have such low power. thirdly, unless you have a frequency counter or a radio scanner, you may be outside the band. fourthly, you can often find used FM MP3 car transmitters with lots of bells and whistles for a few bucks, so no point making your own.

Anonymous

Anonymous Thu 22 Oct 2015 08:14:43 No.891698 Report Delete

Quoted By: >>891705

>>891693
Yeah, several, using basically the same circuit as you.
>any help
Build it on an actual PCB. Or on a pad-per-hole board. Or use air wiring. Or whatever, but forget breadboards.
Also, you might need to experiment a little with the coil dimensions to get the frequency to a correct range.

Anonymous

Anonymous Thu 22 Oct 2015 08:24:10 No.891700 Report Delete

Quoted By:

>>891697
>no point making your own.
It's a simple circuit even a newbie can build, having a relatively interesting function in comparison to its simplicity.
While car mp3 transmitters are black boxes suitable for anus insertions and not much anything else.

I agree that OP's circuit sucks as a transmitter, though.

Anonymous

View Same Google ImgOps iqdb SauceNAO Schematic.jpg, 887KiB, 2550x1431

Anonymous Thu 22 Oct 2015 08:25:28 No.891702 Report Delete

Quoted By: >>891707

>>891697
well, I got this schematic from an instructables project. The circuit seemed to work pretty well. This one has frequency between 88 to 108 Mhz so it's fairly easy to scan with my mobile radio. And making seems more fun than buying;D

Anonymous

Anonymous Thu 22 Oct 2015 08:27:57 No.891705 Report Delete

Quoted By:

>>891698
hey thanks for the reply, I used this site to calculate coil inductance http://hamwaves.com/antennas/inductance.html

Anonymous

Anonymous Thu 22 Oct 2015 08:32:29 No.891707 Report Delete

Quoted By: >>891710

>>891702

the drawing says the coil is 8-10 turns close-wound. yours is 4 turns loosely wound. makes a huge difference.

Anonymous

Anonymous Thu 22 Oct 2015 08:50:19 No.891710 Report Delete

Quoted By:

>>891707
according to the drawing, I need a 0.1micro Henry inductance, calculated it on this site http://hamwaves.com/antennas/inductance.html
coil stats are D=10mm, N=4, l=14mm, d=0.8mm, f=100Mhz

Anonymous

Anonymous Thu 22 Oct 2015 09:06:48 No.891715 Report Delete

Quoted By: >>891719 >>891740

i would place more trust on the text than on the value in the schematic, because that reflects the actual instructions the guy followed in making the circuit, whereas the value in the schematic is an unknown, maybe measured on an instrument that cant possibly show such a low value accurately.

hate to ask, but was the insulation removed from the end of the coil?

Anonymous

Anonymous Thu 22 Oct 2015 09:18:13 No.891719 Report Delete

Quoted By:

>>891715
hey thanks, I am making a new coil as mentioned in the text, will inform you when done.
Yes, I had thoroughly filed the ends of the coil:D

Anonymous

View Same Google ImgOps iqdb SauceNAO 1445485162569_1.jpg, 40KiB, 652x723

Anonymous Thu 22 Oct 2015 09:43:21 No.891731 Report Delete

Quoted By:

http://www.instructables.com/id/The-Ultimate-FM-Transmitter/

Anonymous

Anonymous Thu 22 Oct 2015 10:27:34 No.891740 Report Delete

Quoted By: >>891775

>>891715
Made a new one but no luck. Godammit why doesn't it work!! took diameter of 0.6cm, 7 turns and filed both ends. Shall I make a pcb for this one or shall I experiment with more coils??
>>891729
haha I did not had any 4.7pf so connected 7 33pf in series

Anonymous

View Same Google ImgOps iqdb SauceNAO 1445495442414.jpg, 182KiB, 935x783

Anonymous Thu 22 Oct 2015 12:31:40 No.891775 Report Delete

Quoted By: >>891777 >>891778

>>891740
you have the e and c leads on both transistors wired in reverse.

Anonymous

View Same Google ImgOps iqdb SauceNAO TO-92-common-pinouts.png, 25KiB, 720x460

Anonymous Thu 22 Oct 2015 12:38:07 No.891777 Report Delete

Quoted By: >>891817

>>891775
>This is why we can't have nice things

Anonymous

Anonymous Thu 22 Oct 2015 12:41:20 No.891778 Report Delete

Quoted By:

>>891775
I'm using BC 548 and 547 transistors.

Anonymous

Anonymous Thu 22 Oct 2015 14:03:49 No.891817 Report Delete

Quoted By:

>>891777
Seriously.. Can't everyone agree to a common pin-out like in basically everything else.

Anonymous

Anonymous Thu 22 Oct 2015 21:47:33 No.891965 Report Delete

Quoted By: >>892022

>>891693
I saw this exact thread 2 months ago....am I eating pasta?

Anonymous

Anonymous Fri 23 Oct 2015 02:17:20 No.892022 Report Delete

Quoted By:

>>891965
This is a very well known newbie project. Lots of people build these.

Subject

Name

E-mail

Password

Capcode	All Only User Posts Only Verified Posts Only Moderator Posts Only Manager Posts Only Admin Posts Only Developer Posts Only Founder Posts
Show Posts	All Only With Images Only Without Images Only Spoiler Images Only Non-Spoiler Images
Deleted Posts	All Only Deleted Posts Only Non-Deleted Posts
Ghost Posts	All Only Ghost Posts Only Non-Ghost Posts
Post Type	All Only Sticky Threads Only Opening Posts Only Reply Posts
Results	All Grouped By Threads
Order	Latest Posts First Oldest Posts First

On these boards

Your latest searches

fm transmitters