[TowerTalk] Static Drain Resistor in Arrestor

[maflukey at gmail.com]

I use a static drain choke in my homebrew arrestors.   ANT port gets 31 turns of 18 AWG Thermalize on an Amidon T106-1 shunted to ground with a Littlefuse CG3 1.5kV GDT across it.    TRX port gets a 220k 1/4w real carbon resistor shunted to ground.    ANT to TRX ports are connected with a pair of 8200 pF 3kV ceramics in parallel.    Component leads are kept short and each assy is mounted in a 2.5 x 2.5 x 1.5 aluminum box and secured to the station service entrance ground plane.   Measured insertion loss and SWR are negligible from 160m to 10m and impedance to ground falls off rapidly below about 200 khz.   GDT will handle legal limit at better than 3:1 SWR.   For receive only antennas I substitute a Bourns 2027-07-CLF which is rated at 75V sparkover.    I have about 20 of these in service and they cost a fraction of what the commercial units cost.

73
Matt
KM5VI