Just curious, Dave -
Have you ever looked with an O-scope to see what presents itself
on an open wire or conductor in the vicinity of a T-storm?
Most O-scopes are 1 MOhm input Z, and one can still see DC
offsets being developed, and, of course, inter/intra-cloud plus
cloud to ground strikes present pulses many times higher than
what the DC offset values are.
I've done this with a non-DC grounded 2m antenna, and I've got
to imagine a longwire or 80m dipole would be a whole lot worse
than the 5 or six foot of 'conductor' I had on the 2m gain collinear
I used for some observations a few years back.
My thinking here is that 20 M Ohms will indeed bleed off static
charge, but perhaps a value lower might ought be used (as
suggested, as used) by others for a little better effectiveness.
Unless you do expect direct hits in which case the 20 kV rated
20 Meggers would probably survive.
de AA5CT Jim
-----------------------------------------
On Saturday, September 18, 2021, 6:35:18 AM CDT, Dave <dave@nk7z.net> wrote:
Thanks gents... The resistors I am using are 10 M, 20KVs. I will build
a small chassis and put them on inside, with a pair of SO-239s.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 9/17/21 6:25 PM, Jim Brown wrote:
> On 9/17/2021 5:54 PM, David Eckhardt wrote:
>> The value is anything over 10 kohms. The disturbance
>> to the 50-ohm impedance is completely negligible. The rule-of-thumb
>> on the
>> resistor value is something over 10X the system impedance. I've even
>> used
>> 1k successfully.
>
> A limiting factor for low values is dissipation in the bleed resistor.
>
> 73, Jim K9YC
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