[Elecraft] Elecraft RF Probe

[Jack Brindle]

My brain got got a little ahead of my fingers.

That should be  _without_ extinguishing the diode...

Oops...

On May 22, 2006, at 6:47 PM, Jack Brindle wrote:

> Interesting solution. Be aware that neon lamps fire at about 60-70  
> volts. At that voltage you have _definitely_ exceeded the PRV of a  
> 1N4148! You might want to consider a heavier diode in this  
> application - the 1N4007 should take quite a bit higher PRV,  
> allowing the neon lamp to illuminate with extinguishing the diode.
>
>
> On May 22, 2006, at 6:25 PM, Mike Scott wrote:
>
>> Now, that solution shows the power of the group!
>> All this piker could do was look up a 200V diode or suggest  
>> connecting two
>> in series.
>>
>> When the NE-51 lights you know you have exceeded the diode reverse  
>> voltage!
>> And it's time to add a resistance pad.
>>
>> Mike Scott
>>
>> AE6WA
>> Tarzana, CA
>>
>> Elecraft KX1
>> 40M Inverted V
>> 20M Dipole
>>
>>
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net
>> [mailto:elecraft-bounces at mailman.qth.net]On Behalf Of Al Gulseth
>> Sent: Monday, May 22, 2006 5:44 PM
>> To: elecraft at mailman.qth.net; srife at swbell.net
>> Subject: Re: [Elecraft] Elecraft RF Probe
>>
>>
>> Funny you should mention that -- just in the past few days I was  
>> browsing
>> through an old [1968 edition] ARRL "Hints and Kinks". In an  
>> article titled
>> "Diode Protection for the Heath R.F. Probe" the author suggested  
>> adding a
>> NE-51 neon lamp across the diode (a solution he came up with after  
>> frying
>> "three or four" 1N34s). This should work for the Elecraft probe as  
>> the
>> schematic shown in H&K for the Heath probe is virtually identical  
>> to the
>> schematic in the K1 manual (the only difference is a .005 vs. .01  
>> cap for
>> the
>> input coupling and the polarity of the diode).
>>
>> 73 es GL, Al
>>
>> On Mon May 22 2006 06:53 pm, elecraft-request at mailman.qth.net wrote:
>>> Date: Mon, 22 May 2006 17:22:23 -0500
>>> From: "Stan Rife" <srife at swbell.net>
>>> Subject: [Elecraft] Elecraft RF Probe
>>> To: <elecraft at mailman.qth.net>
>>> Message-ID: <007701c67dee$339355a0$6401a8c0 at stansdesktop>
>>> Content-Type: text/plain;       charset="US-ASCII"
>>>
>>>         I forgot to mention that I put a 1N4148 in and it seems  
>>> to have
>>> taken it out too.
>>>
>>>
>>>         I put too much voltage on my poor probe. Is there a  
>>> heavier diode
>>> that will take a little more voltage, say around 70v, that I can  
>>> replace
>>> the 1N31A with?
>>>
>>>
>>> Stan Rife
>>> W5EWA
>>> Houston, TX
>>> K2 S/N 4216
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>
>
> -Jack Brindle, W6FB
> ====================================================================== 
> =
>
>
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-Jack Brindle, W6FB
=======================================================================