[Elecraft] Remoting KAT500 to base of antenna

Thu Jan 21 11:04:35 EST 2016

Dear Walter,

Please see Gore's website where this is all explained.

http://www.gore.com/en_xx/products/venting/protective/index.html

It is the way professionals do this, they don't use bits of gauze, wicks made from shoe laces or any of the other amateur solutions seen ;-)

73 from David GM4JJJ

> On 21 Jan 2016, at 15:48, Walter Underwood <wunder at wunderwood.org> wrote:
> 
> Gore-Tex might let moisture out, but it might let it in. Moisture migrates from the more humid side of the membrane to the less humid side. It is a pretty slow process.
> 
> wunder
> K6WRU
> Walter Underwood
> CM87wj
> http://observer.wunderwood.org/ (my blog)
> 
>> On Jan 20, 2016, at 11:39 PM, Ian White <gm3sek at ifwtech.co.uk> wrote:
>> 
>> 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
>>> ______________________________________________________________
>>>>>> Elecraft mailing list
>>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>>> Post: mailto:Elecraft at mailman.qth.net
>>>>>> 
>>>>>> This list hosted by: http://www.qsl.net
>>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>>> Message delivered to d.cutter at ntlworld.com
>>>>>> <mailto:d.cutter at ntlworld.com>
>>> ______________________________________________________________
>>>>> Elecraft mailing list
>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>>> <http://mailman.qth.net/mailman/listinfo/elecraft>
>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>> <http://mailman.qth.net/mmfaq.htm>
>>>>> Post: mailto:Elecraft at mailman.qth.net
>>> <mailto:Elecraft at mailman.qth.net>
>>>>> 
>>>>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>> <http://www.qsl.net/donate.html>
>>>>> 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.
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> ______________________________________________________________
>>>> Elecraft mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:Elecraft at mailman.qth.net
>>>> 
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>> Message delivered to d.cutter at ntlworld.com
>>> 
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:Elecraft at mailman.qth.net
>>> 
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to gm3sek at ifwtech.co.uk
>> 
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to wunder at wunderwood.org
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to gm4jjj at yahoo.co.uk