[Elecraft] Remoting KAT500 to base of antenna

Thu Jan 21 02:39:14 EST 2016

The key point about a semi-permeable vent is that it blocks liquid water
(and insects) from getting into the enclosure, but *always* allows water
vapor to escape.  As David points out, plain mesh won't do that under
all conditions.

In the UK, an equivalent to the Gore-Tex engineered vents is available
from Farnell for about £5 ($7.50). Part numbers 2308394 (black) or
2308395 (grey).

CPC normally has them a little cheaper (part numbers EN83188 or EN83189)
but they are currently out of stock.

Compared with the value of the KAT500 inside the enclosure, a properly
engineered semi-permeable vent is a very good investment.

73 from Ian GM3SEK

>-----Original Message-----
>From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of
>David Cutter
>Sent: 21 January 2016 07:08
>To: Lewis Phelps; Elecraft at mailman.qth.net
>Subject: Re: [Elecraft] Remoting KAT500 to base of antenna
>
>Yes, but the weight of water eventually pushes it through - it's cheap
but
>not perfect. If you use a 20mm fitting as I did back then, water
accumulates
>inside until a large droplet forms then exits. The Gortex is better but
more
>$ £.
>
>David, G3UNA
>
>
>----- Original Message -----
>From: "Lewis Phelps" <lew at n6lew.us>
>To: <Elecraft at mailman.qth.net>
>Sent: Wednesday, January 20, 2016 8:03 PM
>Subject: Re: [Elecraft] Remoting KAT500 to base of antenna
>
>
>> But might not this re-introduce the surface tension problem?
>>
>> Lew N6LEW
>>
>>
>>> On Jan 20, 2016, at 10:18 AM, David Cutter <d.cutter at ntlworld.com>
>wrote:
>>>
>>> From my work in the food industry (if memory serves), critter
invasion is
>>> prevented with 0.64mm square nylon netting.  This is common in the
>>> dress-making industry.  (I think it can also be found as a stainless
>>> steel gauze). This can be glued over a breather (drip) hole in the
base.
>>>
>>> David
>>> G3UNA
>>>
>>>
>>> ----- Original Message ----- From: "Edward R Cole"
<kl7uw at acsalaska.net
>>> <mailto:kl7uw at acsalaska.net>>
>>> To: <Elecraft at mailman.qth.net <mailto:Elecraft at mailman.qth.net>>
>>> Sent: Wednesday, January 20, 2016 8:29 AM
>>> Subject: Re: [Elecraft] Remoting KAT500 to base of antenna
>>>
>>>
>>>> Fred,
>>>>
>>>> Your high desert climate will probably produce less condensation
than
>my
>>>> sub-arctic/maritime environ.  What I do for enclosures is to not
seal
>>>> them airtight but provide good drain openings which air can
exchange.
>>>> Of course the shelter is made to repel direct rain/snow.
>>>>
>>>> I suspected that my TR relays were "freezing up" at lower temps
making
>>>> the action delayed so I used some big aluminum  Dale resistor
strapped
>>>> onto the relays to add direct heat by conduction.  I happen to have
28v
>>>> equipment so used 28v thru the resistors to produce heat within
their
>>>> wattage rating (used 40w resistors at both relays).  Of course this
also
>>>> provided some heating of the ambient air of the enclosure which
helped
>>>> keep moisture from forming even in 90% humidity of the fall.  It
rains
>>>> 8-days with one day off from August to October when temps finally
>drop
>>>> below freezing and rain becomes snow.  You don't have anything near
>>>> that.
>>>>
>>>> One thing I have noticed about drain holes in some equipment is
they
>are
>>>> too small to allow water to drop free due to surface tension and in
my
>>>> environ that results in the weep holes freezing tight.  I drill
them out
>>>> to 1/4 inch.  Of course if you are prone to insect/archnid invasion
that
>>>> is problematic.
>>>>
>>>> PS: I lived five years in the high Mojave Desert so know all about
>>>> "critters of the desert" (never stick your hand into a confined
space
>>>> before kicking it to see what crawls out or "rattles"!
>>>>
>>>> 73, Ed - KL7UW
>>>> ------------------------------------------
>>>>
>>>> 3.  Reno/Sparks is a high desert [4,500'] directly adjacent to the
>>>> Carson Range and Sierra Nevada [really big mountains].  Winter
temps
>go
>>>> down into single digits, it does snow/rain.  Should I do anything
to
>>>> prevent condensation in the weatherproof box [light bulb, drain
hole,
>>>> ???].
>>>>
>>>> 73,
>>>>
>>>> Fred K6DGW
>>>> - Northern California Contest Club
>>>> - CU in the Cal QSO Party 1-2 Oct 2016
>>>> - www.cqp.org
>>>>
>>>>
>>>> 73, Ed - KL7UW
>>>> http://www.kl7uw.com
>>>>    "Kits made by KL7UW"
>>>> Dubus Mag business:
>>>>    dubususa at gmail.com
>>>>
>>>>
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>>>> <mailto:d.cutter at ntlworld.com>
>>>
>>>
>______________________________________________________________
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>>> Message delivered to lew at n6lew.us <mailto:lew at n6lew.us>
>> Lew Phelps N6LEW
>> Pasadena, CA DM04wd
>> Elecraft K3-10 / KXV144 / XV432
>> Yaesu FT-7800
>> Lew at N6LEW.US
>> www.n6lew.us
>>
>> Generalized Law of Entropy: Sooner or later, everything that has been
put
>> together will fall apart.
>>
>>
>>
>>
>>
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>
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