[Boatanchors] Question

[Carl]

The Cushcraft Blitz Bug of the 50's and 60's used the spark gap idea. 
Many hams adapted a regular sparkplug since they were free and non 
resistor types were still in wide use.

Carl
KM1H


----- Original Message ----- 
From: "Mike WE0H" <we0h at yahoo.com>
To: <boatanchors at mailman.qth.net>
Sent: Tuesday, August 05, 2008 11:29 AM
Subject: Re: [Boatanchors] Question


> Wow perfect!!! I was thinking you guys were talking coax...hi hi...I 
> wonder how bad the impedance bump would be with coax using the 
> sparkplug sparkgap method? Might be neat watching the 'plugs with 
> nearby thunderstorms. Wonder if they'd spark blue or what color? hi 
> hi...
>
> GM all,
> Mike
> WE0H
>
>
> K0DAN wrote:
>> Mike's right, i was the presence or absence of a resistor...the arc 
>> voltage may or may not be an issue as I previously stated.
>>
>> All my comments were related to balanced line feeder...I use nominal 
>> 600 ohm balanced line, approx 6" spacing.
>>
>> I hope my ASCII "art" comes out OK:
>>
>>
>> TO ANT <--------------o------------> TO RIG
>>                                       ||
>>
>>
>> TO ANT <--------------o------------> TO RIG
>>                                       ||
>>
>>
>>
>>
>> The    o    symbol are the sparkplugs
>>          ||
>>
>>
>> The open-wire feed goes straight to the shack, but at the exterior 
>> entry point you drill a block of aluminum or copper (if you can still 
>> afford copper!), thread the holes, and insert the sparkplugs. Also 
>> drill a hole for a bolt, which connects to your ground system. Mount 
>> the metal block on suitable wall, pole, etc. Inside the shack you can 
>> also install a heavy duty DPDT knife switch (one side to ground 
>> system) and/or connect the open-wire feed to banana plugs, so when 
>> you have the big thunderstorms, you can easily disconnect the 
>> equipment from the antenna network.
>>
>> I wouldn't recommend trying to do this with a coax feed....you'd mess 
>> up the impedance of your system.
>>
>> For coax, Polyphasers, Alpha Delta, or other gas-discharge surge 
>> suppressors are the right choice.
>>
>> GL es 73
>>
>> Dan
>> K0DAN
> _______________________________________________
>