well, as has been commented, if it was not ordered with down-tilt, there will be none at any freqency you put into it, as all elements are exactly in-phase
since the method of acheiving down-tilt was to make the feeds to the lower elements shorter, if it originall had down-tilt I'd venture that the down-tilt would decrease with decreasing frequency (less phase difference) I think............. Gary ----- Original Message ----- From: n9wys To: Repeater-Builder@yahoogroups.com Sent: Saturday, June 07, 2008 11:17 AM Subject: RE: [Repeater-Builder] Re: antenna suggestions for 440mhz Thanks Gary. I was looking for more of a "generic" answer along the lines of, "As you move down in frequency, electrical downtilt ____." (Enter INCREASES or DECREASES here as necessary -- if this is the case.) I am also wondering if 20MHz on the receive is far enough off to cause a problem. Remember, this stick is within 1 MHz of the bottom of its range on TRANSMIT, and well below it on Receive. So this is why I ask about adverse effects. Not that I'm thinking of scrapping it, but I'm just trying to figure out why I didn't gain the receive sensitivity/coverage I thought I would with the added gain. With all this talk about downtilt... if that is what is happening here, that would explain why I'm experiencing what I am on receive. Or am I worrying about gremlins?? Mark -N9WYS -----Original Message----- From: Repeater-Builder@yahoogroups.com On Behalf Of Gary Glaenzer Sent: Saturday, June 07, 2008 10:30 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: antenna suggestions for 440mhz down-tilt is specified when ordering the unit other than the original paperwork, the only method would be to have it tested on a test range and that would probably cost more than ordering a new one............ Gary ----- Original Message ----- From: n9wys To: Repeater-Builder@yahoogroups.com Sent: Saturday, June 07, 2008 10:22 AM Subject: RE: [Repeater-Builder] Re: antenna suggestions for 440mhz In fear of moving off topic... I'd like to ask how one can determine the electrical downtilt of an antenna? I just put into service a RSF/Celwave Super StationmasterR Model 10017-6 that is designed for 925-960 MHz on my 927.5250 repeater. The added gain factor of the antenna (an additional 4dBd over what was previously in place - a Decibel DB586-Y) does not seem to benefit the receive (at 902 MHz). I gained what seems like a little extra receive range, but not equal to what I seem to have gained in transmit coverage. This discussion thread leads me to wonder if maybe some electrical downtilt may be affecting the receive frequency? Is this possible? Antennas are not my strong point. ;-) Thanks, Mark - N9WYS ------------------------------------ Yahoo! Groups Links No virus found in this incoming message. Checked by AVG. Version: 8.0.100 / Virus Database: 270.0.0/1489 - Release Date: 6/7/2008 11:17 AM
