#### Your RF CafeProgenitor & Webmaster

Kirt Blattenberger
BSEE
KB3UON
EIEIO

Carpe Diem!
(Seize the Day!)

5th MOB:

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse riding website

# RF design - simple question - RF Cafe Forums

 The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Below are all of the old forum threads, including all the responses to the original posts. -- Amateur Radio -- Antennas-- Circuits & Components-- Systems-- Test & Measurement

 Post subject: RF design - simple question Posted: Wed Mar 07, 2007 3:50 pm
 Lieutenant

Joined: Wed Mar 07, 2007 3:42 pm
Posts: 1
What effect does return loss have on Transmit Power?
Is it a one to one correlation?

eg. Tx power is 30 dB
RL = -12 dB

What is actually transmitted?

Thanks

 Post subject: Posted: Wed Mar 07, 2007 5:53 pm

Joined: Sun Aug 03, 2003 2:02 pm
Posts: 676
Location: Erie, PA
 Greetings matrixrf:Return loss is the relative power of the reflected part of the signal, and the remaining power gets through to the antenna. For your case, the reflected signal is 30 dBm - 12 dB = 18 dBm. To get the final transmitted power number, you need to convert those powers to watts, subtract, then convert back to a dBm value.30 dBm = 1000 mW (incident power)18 dBm = 63.1 mW (reflected power)(1000 - 63.1) mW = 936.9 mW (transmitted power)936.9 mW = 29.7 dBmFor dBm <--> mW conversion see here: http://www.rfcafe.com/references/electrical/mw2dbm.htm _________________- Kirt Blattenberger RF Cafe Progenitor & Webmaster

Posted  11/12/2012