Fwd: [Premium-Rx] Lightning hitting your Premium RX

Fri Apr 8 09:22:19 EDT 2005

A neon bulb across the input works FB for draining off static charges.  A NE-2 fires at about 60 volts, IIRC.

Don't try this if you're gonna xmit thru it - you'll wreck the bulb.

73 John

----- Original Message -----
From: Peter Gottlieb <nerd at verizon.net>
Date: Friday, April 8, 2005 0:35 am
Subject: Re: Fwd:  [Premium-Rx] Lightning hitting your Premium RX

> Where to start.
> 
> A spark gap will protect the equipment even when it is on but the 
> TR relay 
> scheme only protects when it is off (unless you count the contact 
> gap).
> An induced strike, if close enough, does as advertised and does 
> indeed induce 
> significant voltages.  Last year I had a nearby strike and while 
> none of my 
> radio gear was affected I did lose about half the ports on my home 
> 100 Base T 
> network switch and also a few computer network cards.  And those 
> things are 
> pretty well isolated.
> 
> As mentioned, lightning has a very fast risetime and thus high 
> energy in high 
> frequencies.  What this means is that any protection circuits must 
> be designed 
> with good RF design practices.  They must also be installed 
> properly.  One 
> anecdote from my power protection days:  we found that customers 
> who had a pile 
> of power cords all jumbled up behind the computer were not always 
> protected by 
> our surge suppresors which we absolutely knew were effective.  It 
> turned out 
> that the lightning pulses were being induced between the line side 
> of the surge 
> strip and the load side through the power cords!
> 
> I have TR relays on my rigs but they are set up for protection 
> from excess RF. 
> For example, when my RF-350K transmits a Dowkey relay pulls in and 
> disconnects 
> the RF-590A from its separate HF antenna and shorts its input.  
> Crude, but 
> effective, but does nothing for lightning protection.
> 
> Peter
> 
> 
> Eugene Hertz wrote:
> > Howdie. thought I'd run something by you. I had an idea for 
> lightning 
> > protection, not direct hit, but induced voltage. I have been 
> seeing 
> > these gizmos that have a gap which the spark will jump if the kv 
> goes 
> > too high and then short to ground. My idea was to use a TR relay 
> mounted 
> > outside in a weather proof enclosure. In the energized state, 
> the 
> > antenna connects to the shack, in the unenergized state the 
> antenna 
> > connects directly to ground.  I thought I might run the relay 
> from some 
> > power source either in my Tx or Rx. Whch would require that, 
> say, the Rx 
> > would need to be on otherwise the antenna is grounded. 
> > 
> > Would this accomplish the same thing as the gaps? Or is there 
> something 
> > superior to the gaps? Also, I know the gap devices need 
> replacing every 
> > so often, would the TR relay get zapped with induced voltage on it?
> > 
> > -----Original Message-----
> > From: Gary Mitchelson - N3JPU [n3jpu at speakeasy.net]
> > Sent: Tuesday, April 5, 2005 03:58 PM
> > To: ''Cecil Acuff'', ''Premium-Rx (E-mail)''
> > Subject: RE: [Premium-Rx] Lightning hitting your Premium RX
> > 
> > The hybrid AC protectors provide the lighting protection on the 
> AC line
> > side.
> > 
> > The crude drawing shows the ground lines going out straight, the 
> do really
> > curve around but do not go all the way around, a long way to do 
> that.> Hopefully the runs I have will launch enough of the strike 
> into the ground.
> > Won't know until it happens though. Didn't have access to a 
> Megger so do 
> > not
> > know what the final impedence. I have good soil for conductivity 
> so I'm
> > hoping it's down below 5 ohms.
> > 
> > Their HF protector goes down to 100KHz.
> > 
> > Documents: http://www.arraysolutions.com/Products/ice/10.html
> > 
> > Products: http://www.arraysolutions.com/Products/ice/3.html
> > 
> > Polyphaser's article on Ham Shack protection
> > http://www.polyphaser.com/ppc_TD1016.aspx
> > 
> > Gary Mitchelson
> > N3JPU Montgomery Co. MD FM19
> > http://www.mitchelson.org/
> > 
> > 
> > 
> > -----Original Message-----
> > From: Cecil Acuff [chacuff at cableone.net]
> > Sent: Tuesday, April 05, 2005 16:39
> > To: Gary Mitchelson - N3JPU; 'Premium-Rx (E-mail)'
> > Subject: Re: [Premium-Rx] Lightning hitting your Premium RX
> > 
> > 
> > Gary,
> > 
> > I looked over your pictures. Looks great. Typical with what I see
> > at most of the commercial tower sites I frequent. The question 
> remains as
> > to whether you have your house electrical ground tied to your tower
> > grounding system. It appears you do by virtue of the AC power 
> protectors> plugging into AC outlets in your shack. Curious why 
> the ground runs with
> > the rods went out at angles away from the shack. Common wisdom 
> in the
> > commercial tower business is to create a ring around the 
> building being
> > protected. May have been inconvenient to circle the house...
> > 
> > What is the lower end frequency of the Coax protectors? I 
> typically use
> > Polyphasor systems at work but that is for VHF/UHF stuff. I'm 
> not sure
> > their stuff goes down to LF or not. Seems protecting to 500Khz 
> or even to
> > 1.8 Mhz is a little more difficult.
> > 
> > You've done what most folks are unwilling to do...that is to 
> spend as much
> > on your protection systems as a new high end transceiver costs. 
> Should be
> > well protected!
> > 
> > What did your final ground point impedance end up being?
> > 
> > 
> > _______________________________________________
> > 
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> > 
> > 
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