My Antenna tower

Hi After having found SWR problems and erratic behaviour of my amplifier at high power levels I started checking the whole antenna system. First I found after calculation that my powersplitter was not exact 50 ohms but "only" 48 ohm. Resulting that it transforms the exact 50 ohm antennas to 46 ohm.. so a mismatch. I build a new splitter with exactly the right dimensions Outer conductor square 32mm inside diameter and inner conductor round 15mm outside diameter. This results in exact 50 ohm. After replacing it, I terminated it with 4x 50ohm 10W terminators, applied power to it and found a good SWR, but not flat over a large part of the spectrum. On 142 MHz impedance was only 35 Ohm while on 144 it was exact 50 ohm, then on 149MHz another peak. This told me that there is some impedance mismatch in the cable. The first 35m is 7/8 cellflex.. After terminating that piece with 50 ohm SWR was flat form 120 to 160 MHz so it must be the last part of the cable 15m Ecoflex-15 from h

After having serious Amplifier problems I finaly found out my tube was glitching so every now and then.. My PA is in a remote room, I used it in this set up for years and years. Just tuned it once and no worries about the PA just switch it on and operate. But a few months ago I had a small failure it looked like the HT fuse was blown by accident, also the mains fuse was broken and PA was without cooling after that as the fan wasn't running anymore. The Anode couldn't radiate it's heat.. After fixing the fuses all worked again. Same output power but now more often the HT fuse went QRT without (pre)notice. I suspected the Bias circuit as it was just 2 transistors some resistors and a potmeter. so I rebuilded the Bias circuit with a TL-431A regulator and a TIP-147 darlington PNP transistor. Aligned it at 40V for 150mA bias current. All was working fine again.. After 30min of standby I wanted to transmit but NO HT.. All was left which could cause the problem was the tube.. I h