Brian, you can extend the frequency range with external equalization to some extent. This is some what dependent on the overall slope and depths of the roll off in the original circuitry. It always results in phase shifts of the audio where a normal harmonic in a persons voice get shifted so as to change the shape of the output wave form. This shape change can make a difference in the requirement of peak power from the transmitter that it may not be able to do with out reducing overall power. On the other hand it could change the shape in such a way as to reduce the peak demand on the XMTR giving the XMTR more head room so you might be able to put out a little more average power than before. But be assured that there will be a phase shift in the lower frequencies fundamentals with respect to the harmonics in the male voice causing the peak demand to change one way or the other.
If the extending of the frequency is too great in the low frequency end and not enough in the high frequency end then intelligibility will be lost on weak signals during demanding circumstances. One must of course watch out for over drive of a pre amp stage while trying to extend its roll off. John, WA5BXO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of A.R.S. - WA5AM Sent: Wednesday, February 20, 2008 5:02 PM To: Discussion of AM Radio in the Amateur Service Subject: [AMRadio] T3 Mod iron specs - Audio limitations, harmonics, etc. Anyone know the approximate "designed" frequency range for a T-368 modulation transformer? Also, if there is a website out there somewhere that has stock audio specs on the popular commercial and military transmitters, I would be interested in seeing it. I think I know the answer to this, however I know there are a lot of you out there that have a lot more knowledge than I do on the specifics... Let's say your transmitter is limited for 200 to 3000 cycles in the audio section, either by coupling caps, cathode bypass, cathode resistors, plate loading, and any transformers... what is the result of using an external EQ and audio chain that pumps audio from the mic that is beyond either end of the audio range the transmitter is allowed by design to pass? I think this is a common mistake that a lot of us make that can cause some serious harmonics and other artifacts. I'd like to see a discussion on this if any of you experts would care to chime in ;) 73 Brian / wa5am -- "Money is only temporary, radios are forever" - Jim Little aka "the old dawg"/K5BAI ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.