Re: Topband: RX antenna switching - unused ports
Brad, I have a 12x1 commercial Panasonic video switcher which is passive and terminates in 75 ohms all unused ports. I used 1/2 wave feed lines which conceivable repeats the 75 ohm termination at the Beverage matching transformer. I also use several 1:1 (DXE) isolation boxes about 30 feet from several Beverages to reduces feedline pickup coupling back into the Beverage matching transformer. On 6/8/2017 8:06 AM, Maciej Wieczorek wrote: Hi Brad, what I can say from my perspective - in the last 10 years I have tried both grounding and terminating through 75ohm resistor. With the terminating I see absolutely no pattern distortion on my Beverage's, which was not so obvious when direct grounding was used. My Bev's often are crossed 45 deg, height is 1,8-2,0m. I use only isolated transformers / separate windings. 73's Mac SP2XF / SN2M - Original Message - From: "Brad Denison" To: Sent: Thursday, June 08, 2017 1:54 PM Subject: Topband: RX antenna switching - unused ports All, I am working a homebrew RX antenna switch box for my beverages, flags and shared apex loop array and am looking for design advice. Can someone educate me on the proper way to handle unused ports: 1) Leave all unused ports open 2) Ground all unused ports 3) Terminate unused ports to 75 ohm I have seen various commercially available switch boxes with all of these configurations but it is not clear to me if any of these variations are best, i.e does it matter? Thanks, Brad, W1NT _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RX antenna switching - unused ports
Hi Brad, what I can say from my perspective - in the last 10 years I have tried both grounding and terminating through 75ohm resistor. With the terminating I see absolutely no pattern distortion on my Beverage's, which was not so obvious when direct grounding was used. My Bev's often are crossed 45 deg, height is 1,8-2,0m. I use only isolated transformers / separate windings. 73's Mac SP2XF / SN2M - Original Message - From: "Brad Denison" To: Sent: Thursday, June 08, 2017 1:54 PM Subject: Topband: RX antenna switching - unused ports All, I am working a homebrew RX antenna switch box for my beverages, flags and shared apex loop array and am looking for design advice. Can someone educate me on the proper way to handle unused ports: 1) Leave all unused ports open 2) Ground all unused ports 3) Terminate unused ports to 75 ohm I have seen various commercially available switch boxes with all of these configurations but it is not clear to me if any of these variations are best, i.e does it matter? Thanks, Brad, W1NT _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: RX antenna switching - unused ports
All, I am working a homebrew RX antenna switch box for my beverages, flags and shared apex loop array and am looking for design advice. Can someone educate me on the proper way to handle unused ports: 1) Leave all unused ports open 2) Ground all unused ports 3) Terminate unused ports to 75 ohm I have seen various commercially available switch boxes with all of these configurations but it is not clear to me if any of these variations are best, i.e does it matter? Thanks, Brad, W1NT _ Topband Reflector Archives - http://www.contesting.com/_topband