Maybe I'm taking to "simple" of a view, but could this be some sort of harmonic? However, if my math is correct (and it usually isn't... :-p ) that would be about a 4th order harmonic, I think. (If that's even possible.) Or am I all wet?
Mark - N9WYS -----Original Message----- From: Richard Sharp, KQ4KX [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 05, 2004 9:35 AM To: [email protected] Subject: RE: [Repeater-Builder] 2m repeater IMD issue Well, I considered that too. However, after further study of isolators (and discussing my situation with a manufacturer of isolators) I discovered that a VHF isolator will not stop signals in the 800MHz range from passing through it. An isolator should work great if I was dealing with several VHF transmitters at the same level on the tower. I'm wondering if the IMD is being generated somewhere on the tower, antenna(s), etc.? A bandpass cavity on the tx drops the 800MHz signal levels (as seen at the tx port) from -40dBm to -75dBm. I would think levels of -75dBm "shouldn't" be a problem for the 2m tx? The harmonic filter in the tx should drop the -75 to nearly nothing - right? That's why I'm thinking perhaps the IMD is being generated somewhere else. Although, it does only occur when the 2m tx is on. tnx Richard > -----Original Message----- > From: Charles Miller > > Richard, > > You said that the IMD is only there when YOUR TX in on. If this > is the case > you may need an Isolator for your TX. I had a site that was getting eat > alive with IMD at 150 MHz only when the TX was on. Found out that the IMD > was being generated in the transmitter. Put an isolator on the > thing and no > more IMD. > > Just a thought 8-) > > Charles Miller > > ----- Original Message ----- > > [snip] > > I can see carriers appear and disappear on the rx side when the > tx is on. > [snip] > > Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
