Open Wire Feed Line Arrestor

[Ralph Tyrrell]

Still running my K1 (#1423) on inefficient low
antennas.
I have some trees that will give me good height 50-60'
and orient the main lobe of a double extended zepp
(14MHz) toward Oregon, take notice ECN.

I have come across a device that will keep the antenna
at near DC ground at all times.

http://www.arraysolutions.com/Products/ice/impulse1.html

go down to "Open Wire Arrestor", Model 309

"All units use torroidal inductors and present near
dead DC short on antenna side of arrestor, constantly
draining feedline wires of static and any developed
voltage potential feedthrough breakdown voltage from
input ports to output ports 4,000 to 6,000 volts.
Arrestor units may be placed anywhere in the feedline
at ground level without serious change in tuning, but
small change may be detectable due "to small" increase
in total feedline length caused by size of arrestor
case & circuit."

Just wondering if anyone else has used this or a
similar item and what comments might be made. Just
trying to be save from lightning.
I would also put a DPDT knife switch between the feed
line and the K1 with BL2 to ground the feed line when
not in use.

Thanks all.

73, W1TF, Ty in GA


               
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[Geoffrey Mackenzie-Kennedy-2]

Morning Ralph,

Thank you for sharing the information about these devices, very interesting!

I must confess that I have for decades used NEW sparkplugs with their gaps
suitably set for the maximum peak RF voltage on the line, assuming a high
VSWR, plus some, and with separate static drains placed elsewhere. The
devices that you have found probably provide better protection and are
certainly neater.

Knife switches and I have never got on very well!! I have always been wary
of having to 'throw' a shack installed feeder switch in anger, probably
because Murphy's Law states that this would be the moment when the antenna
system gets zapped. But that's just one coward's opinion.

Good luck with the double extended Zepp.

73,
Geoff
GM4ESD


Ralph Tyrrell wrote on Friday, January 06, 2006 3:07 AM

> Still running my K1 (#1423) on inefficient low
> antennas.
> I have some trees that will give me good height 50-60'
> and orient the main lobe of a double extended zepp
> (14MHz) toward Oregon, take notice ECN.
>
> I have come across a device that will keep the antenna
> at near DC ground at all times.
>
<snip>
>
> Just wondering if anyone else has used this or a
> similar item and what comments might be made. Just
> trying to be save from lightning.
> I would also put a DPDT knife switch between the feed
> line and the K1 with BL2 to ground the feed line when
> not in use.
>
>


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[James Apple]

I used one for 5 or so years with a full wave 80m loop.  It seemed to work
well but I don't think I ever had a hit.

I also had a knife switch, but in case I forgot to throw it or a storm snuck
up on my, I had the ICE unit.

On 1/5/06, Ralph Tyrrell <[hidden email]> wrote:

>
> Still running my K1 (#1423) on inefficient low
> antennas.
> I have some trees that will give me good height 50-60'
> and orient the main lobe of a double extended zepp
> (14MHz) toward Oregon, take notice ECN.
>
> I have come across a device that will keep the antenna
> at near DC ground at all times.
>
> http://www.arraysolutions.com/Products/ice/impulse1.html
>
> go down to "Open Wire Arrestor", Model 309
>
> "All units use torroidal inductors and present near
> dead DC short on antenna side of arrestor, constantly
> draining feedline wires of static and any developed
> voltage potential feedthrough breakdown voltage from
> input ports to output ports 4,000 to 6,000 volts.
> Arrestor units may be placed anywhere in the feedline
> at ground level without serious change in tuning, but
> small change may be detectable due "to small" increase
> in total feedline length caused by size of arrestor
> case & circuit."
>
> Just wondering if anyone else has used this or a
> similar item and what comments might be made. Just
> trying to be save from lightning.
> I would also put a DPDT knife switch between the feed
> line and the K1 with BL2 to ground the feed line when
> not in use.
>
> Thanks all.
>
> 73, W1TF, Ty in GA
>
>
>
> __________________________________________
> Yahoo! DSL – Something to write home about.
> Just $16.99/mo. or less.
> dsl.yahoo.com
>
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>
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>

--

- Jim

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[Ron D'Eau Claire-2]

Thanks for the link. It's an interesting product.  I had three reactions:

1) Note that the upper impedance specification is 600 ohms. Many (most) of
our doublets produce impedances along the feed line much, much greater than
that on some frequencies. That suggests the voltage ratings will be exceeded
as well except at QRP or QRPp power levels.

2) I also noticed that they did not mention any loss figures. Anything tied
between the feeder and ground will have some losses, so how much is of
interest.

3) I would never use it expecting that it'd protect my rig from a close or
direct strike. The surge from a "near miss" will be divided among the
various paths. Even if the device handles hundreds of amps of surge, that
may leave a very destructive current flowing through the rig in parallel.

Ron AC7AC

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[Jack Brindle]

I would take this quite a bit farther. I use open-wire feed for two  
major reasons. 1) It is super low loss no matter the SWR, without  
fear of high voltages burning up the feedline, and, 2) (directly  
related to #1) the antenna becomes inherently broadband with a  
suitable balanced tuner making it useful on 160-10 with just a  
retune. Adding anything (Ls or Cs) along the feedline could directly  
compromise #1 and affect the characteristics of the feedline. It  
would be very interesting to see the schematic of the device, but I  
am very skeptical as to it effects on the antenna system. It would  
probably have far less detrimental effects after that first close  
strike, however...

I am very lucky to live in an area where thunderstorms are pretty  
much non-existent (maybe one a year), but when I was growing up in  
Miami I had to worry about this. Sparkplugs worked very well. I still  
worried though AND made sure the feedlines were thrown out the window  
any time there might be a storm.

As for burying them underground, not MY open-wire line... ;-)

On Jan 6, 2006, at 9:55 AM, Ron D'Eau Claire wrote:

> Thanks for the link. It's an interesting product.  I had three  
> reactions:
>
> 1) Note that the upper impedance specification is 600 ohms. Many  
> (most) of
> our doublets produce impedances along the feed line much, much  
> greater than
> that on some frequencies. That suggests the voltage ratings will be  
> exceeded
> as well except at QRP or QRPp power levels.
>
> 2) I also noticed that they did not mention any loss figures.  
> Anything tied
> between the feeder and ground will have some losses, so how much is of
> interest.
>
> 3) I would never use it expecting that it'd protect my rig from a  
> close or
> direct strike. The surge from a "near miss" will be divided among the
> various paths. Even if the device handles hundreds of amps of  
> surge, that
> may leave a very destructive current flowing through the rig in  
> parallel.
>
> Ron AC7AC

- Jack Brindle, W6FB, ex WA4FIB (Florida), ex WB5KQJ (Louisiana)
------------------------------------------------------------------------
---------------------


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[Stuart Rohre]

The device is stated to have toroid cores on each side of the line conductor
so as to provide a DC short to the antenna side of the box.   On the
transmit side, it may be AC coupled, which is fine when the right size cap
is used for RF.  The cores with their windings act as RF chokes while
allowing a DC bleed off for any antenna charge.

There was a similar device, (maybe the same reviewed in QST (?CQ) with a
photo of the inside and it had pretty much the same circuit.  Think that was
last year or the year before.

-Stuart
K5KVH



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