Antenna Replacement on 100 Foot Rohn 25G (Full) скачать в хорошем качестве

Antenna Replacement on 100 Foot Rohn 25G (Full)

The antenna was replaced for the New Bern, NC Amateur Radio Club. I removed an old Station Master that was designed for 155 MHz, so it was a poor performer on 2-meters. The VSWR was terrible, so I rebuilt a dipole array that I removed from another site. The club representative thought that 4 elements would be too much wind-load for the 25G, so I only used two elements and made a new phasing harness. The coax was OLD, but it was still usable. You can see the old PVC jacket is completely gone... A quick VSWR check showed 70 Watts out after the duplexer and zero reflected. Range tests are still being performed, but it is exceeding expectations. Current ERP is 180 Watts, so once the range tests are complete, I'll do a final alignment to dial in the power so it is not transmitting further than it can receive. Sorry about the whistling, singing and talking to myself. The new antenna is a modified Phelps-Dodge with elements cut for 146 MHz. I used a combination of 75, 50 and 35 Ohm coax for the phasing harness to achieve a 50 Ohm Match at the feedpoint. I also bent new elements as the old ones were too short. Repeater is a Harris MASTR III VHF (150-174) that I modified for 2-meters. I added some brass to the tuning slugs on the receiver front-end and changed a few components. After the mods, the receiver opened squelch at -116dB and it put out 125 Watts. I turned it down to 95 Watts for initial testing. Enjoy!