Here is how my DB-224 was done. You mount it one wave length off the tower at the transmit frequency. Point all four dipoles at the tower. Funny how it works but it will give you near omni for a pattern. This is in the standard antenna placement book for RF engineering. It works well. I have four in our network like this. 1 two meter and 3 222 MHz repeaters. Good luck and 73, Russ, W3CH
----- Original Message ----- From: "kc4fwc" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, August 12, 2005 5:08 PM Subject: [Repeater-Builder] Side mounted DB-224 for omni coverage? > Hello Group, > Have a dual antenna system for a 2M repeater. Decibel DB-222 top > mounted, clears the tower and is oriented for omni-directional > coverage. TX antenna is directly below and is side mounted on the > southwest side of the tower. The antenna is a Celwave PD-340-3 with > dipoles oriented around the mast (omni). It is mounted on the corner > (not the face) of Rohn 25-G and is a factory mount and top sway brace > from Decibel Products and they recommend this for side mounting DB- > 224's. The mount lets the antenna extend around 22 inches from the > leg of the tower. > > I am noticing VERY significant deficiencies in TX coverage back > through the tower, even what I would estimate 8 to 10 dB. In other > directions, it seems as if the coverage is as good as can be > predicted. > > I have heard someone mention that taking all four dipoles on the same > side of the mast and directing the elements straight into the tower > would create more of an omni pattern. I can't remember if this was > for UHF or VHF. I would like to eliminate any deep nulls, no more > than 3 dB down in any direction if possible. Will turning all > elements towards the tower help my situation? 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/
