When calculating the quarter wave sections, you need to use the velocity of propagation of the 75 ohm cable you select.
http://www.arcticpeak.com/antennapages/quaterwavestub.htm From: [email protected] Sent: Friday, December 2, 2016 7:59 AM To: [email protected] Subject: Re: [AFMUG] need to stack 2 900 mhz yagis, what do i need? No need to use a splitter if you are using 75 ohm transmission line transformer. If you use a 900 MHz splitter, just make sure both cables are the same length. If you are using a T, again make sure both cables are the same length, then use a 75 ohm 1/4 wave long section from the T to your regular cable. Two 50 ohm loads come to the T and they are in parallel. That equals a load of 25 ohms presented to the transmitter. The 1/4 wave 75 ohm section transforms that 25 ohms back up to 50 ohms. I would have to display a smith chart to further explain. From: Gino Villarini Sent: Friday, December 2, 2016 5:48 AM To: [email protected] Subject: [AFMUG] need to stack 2 900 mhz yagis, what do i need? Guya I need to stack to 900 mhz yagis to get the add 3db gain, I used to have a M2 Antenna stacking kit somewhere.. But can’t find it. IIRC ill need 1 900 splitter and 2 phased pig tails, 75ohm? Gino Villarini President Metro Office Park #18 Suite 304 Guaynabo, Puerto Rico 00968
