Audio broadcasting

**Pistolen08** · 01-15-2007, 11:37 PM

I am trying to keep my install look stock, so I don't want to have any antennas that would look out of place, and I don't want to remove the factory one, so it seems as though I'm stuck with it. Also, if something happens, and the FCC is knocking at my door I don't want to look suspicious lol (even though I wont be transmitting on commercial frequencies). Once I build the circuit, I can test the antenna and go from there. I just want to freak people out at red lights, etc... lol

**inh** · 01-15-2007, 11:40 PM

then just get an amplifier

**Pistolen08** · 01-15-2007, 11:46 PM

isn't that what the tunecast mod essentially is? If you compare the power outputs before vs. after the pcb is attached, you can notice significant boosts.

**greenman100** · 01-16-2007, 12:05 AM

Originally Posted by Pistolen08

So, if I want to broadcast at 98.7 MHz, one cycle = (1/98700000 ~= 0.00000001032 seconds) and one quarter cycle ~=0.000000002533 seconds, and at traveling at c (the speed of light), the electrons can travel ~=0.7594 km in that time, so the optimal antenna should be 759.4 m tall (2491.47 feet ~= 0.47 miles). lmao

I don't think that will fit in my RSX.

no.

300000000/98700000=3.03m

so a quarter cycle would be about .75m, or 30 inches

**Pistolen08** · 01-16-2007, 07:21 AM

Wow, I was quite a bit off lol.
That sounds a lot more reasonable.
So frequency (Hz) = speed of light (m/s) / wavelength (in a vacuum).

If this is correct, the optimal antenna length for the station 98.7 is 30 inches.
Radio antennas are usually very tall, so how can this be?

Originally Posted by greenman100

no.

300000000/98700000=3.03m

so a quarter cycle would be about .75m, or 30 inches

**inh** · 01-16-2007, 12:26 PM

im sure it has something to with like, if you cna make a 1/4 wavelegth antenna, im sure you can mke a 4x wavelength one too

**2k1Toaster** · 01-16-2007, 12:27 PM

**greenman100** · 01-16-2007, 11:12 PM

Originally Posted by Pistolen08

Wow, I was quite a bit off lol.
That sounds a lot more reasonable.
So frequency (Hz) = speed of light (m/s) / wavelength (in a vacuum).

If this is correct, the optimal antenna length for the station 98.7 is 30 inches.
Radio antennas are usually very tall, so how can this be?

the antenna on your car is about 30 inches, incidentally.

if you are speaking of broadcast antennas, they are that tall to get above obstructions. the actual antenna element is much shorter.

**v1per** · 01-16-2007, 11:48 PM

Yea, the top of the antenna tower (the actual part of the antenna) is like alight bulb while the tower part is just the extension cord.

**Pistolen08** · 01-17-2007, 11:42 AM

Wow, I always thought that the metal supporting the antenna tower acted as the antenna itself. So, if a typical antenna used at a radio station broadcasts 50 miles radius, mine should reach ~1-2 miles do to interference/size/inefficiency. I will try to build the signal amp next week, once I finish my carpc install. Thanks for your help guys.

-Elliot