I have a homework problem I can't solve. This topic wasn't covered in class and the textbook offers no explanation, yet this problem is in the textbook! The problem is as follows:

Given a 100-Watt power source, what is the maximum allowable length for the following transmission media if a signal of 1 Watt is to be received?
a. 24-gauge twisted pair operating at 300kHz
b. 24-gauge twisted pair operating at 1MHz
c. 0.375" coaxial cable operating at 1MHz
d. 0.375" coaxial cable operating at 25MHz
e. optical fiber operating at its optimal frequency

So far I have determined that the total loss from 100W to 1W is 20dB. A twisted pair rated at 0-1MHz has an attenuation rate of .7dB/km @ 1kHz. I tried to manipuate the ratio and came up with 4.8 meters. I have no idea how to approach this problem. Any help would be appreciated.

 

This thread clearly belongs in the homework forum so I have relocated it there.

hgmjr

 

Thanks. I should have known to put a thread titled Homework Help in the Homework Help forum.

 

Hello,

I think you will have to take a look at the theory on transmission lines.
Here is a page from the EDUCYPEDIA with some links on the subject:
http://www.educypedia.be/electronics/transmissionlines.htm

Bertus