[SMCARA] Antenna Setup
Rene Ramirez
w3bnyren at gmail.com
Tue Nov 25 10:56:30 EST 2014
http://www.eham.net/ehamforum/smf/index.php?topic=24185.0;wap2
On Tue, Nov 25, 2014 at 10:55 AM, Rene Ramirez <w3bnyren at gmail.com> wrote:
> Without having a chart infront of me, the loss at HF frequencies shouldnt
> be much more than a 1db tops.
>
> On Tue, Nov 25, 2014 at 10:45 AM, Bill Jones <merc669 at gmail.com> wrote:
>
>> I figured there would be some. How much, maybe not a lot. But that
>> loss could be a contact(s). I was trying to save a buck or two and
>> probably not worth it. And a 125 to 150 foot run should not be that
>> expensive.
>>
>> Bill
>>
>> On Tue, Nov 25, 2014 at 10:39 AM, Daniel Metcalf <kb3uun at gmail.com>
>> wrote:
>> > Bill,
>> >
>> > When I was a teenager I had a job that enabled me to work on the S-3B
>> > Viking II (one of the aircraft I worked on is in the museum parking lot
>> > it has 770 on the side of it). I worked on two projects for that
>> > aircraft namely the AG-65M Maverick Missile Installs where I was in
>> > charge of the wiring harnesses from the fuselage to the weapons pylon
>> > and the second project was a test kit to verify wiring of the aircraft's
>> > radar altimeter. Several S-3s were lost during night-time carrier
>> > operations due to the fact the radar altimeter was indicating that is
>> > was safe to retract the landing gear and flaps and when the pilots did
>> > they stalled and dropped the plane into the ocean. Several crews were
>> > lost. We went to Jacksonville, FL to examine the aircraft from the
>> > Checkmates squadron before their deployment and I am glad we did. With
>> > what we discovered it was amazing the systems worked at all. Anyway I
>> > digress.
>> >
>> > It was working to verify the wiring of the radar altimeter systems that
>> > I became very familiar with using a TDR. This device sent a signal
>> > through the wiring and was able to graphically show us where each of the
>> > bulkhead connectors were and any defects that may have been in the
>> > wiring. While examining a aircraft one day, I was told by an engineer
>> > that at each of those bulkhead connectors we were losing approx. 3db of
>> > signal. Which to put in simple terms, through each bulkhead connector we
>> > were losing approx. half of the signal. Now I understand the frequencies
>> > we use are much much lower than that used by the Radar Altimeter system
>> > and at those higher frequencies it does not take much to cause loss. But
>> > if I am not mistaken there is still some truth in the logic that there
>> > is loss of signal each time we go through a in-line barrel connector. It
>> > may not be 3db like it was in the aircraft but there is some.
>> >
>> > Dan
>> >
>> >
>> > On Tue, 2014-11-25 at 10:03 -0500, Rene Ramirez wrote:
>> >> Honestly. Ive never EVER liked that crap. Its just tar/mastic and if
>> >> you ever have to get into that barrel connector, you are better off
>> >> just cutting it. Either that or a whole bunch of mineral spirits to
>> >> help loosen it. Seriously..cut it.
>> >>
>> >>
>> >> That being said. If you must use a barrel connector use Scotch-3m
>> >> linerless rubber tape and 88+ (its thicker) followed by a liberal
>> >> amount of scotch-kote. That combination is good to like...88Kv,
>> >> buryable and comes off with a little pursuasion from a razor knife.
>> >>
>> >>
>> >> On Tue, Nov 25, 2014 at 9:44 AM, Bill Jones <merc669 at gmail.com> wrote:
>> >> I was going to ask your #2 also since I have the end-fed to a
>> >> post and
>> >> thought of just extending it by 100feet what the downside
>> >> would be if
>> >> I barreled connected it and then sealed it with coax seal
>> >> rather than
>> >> pull a new cable from the shack to the new antenna I was
>> >> thinking of
>> >> to replace the end-fed next year.
>> >>
>> >> Bill
>> >>
>> >> On Tue, Nov 25, 2014 at 8:37 AM, Daniel Metcalf
>> >> <kb3uun at gmail.com> wrote:
>> >> > Good Morning All,
>> >> >
>> >> > Just wanted to get some thoughts on a personal antenna
>> >> installation that
>> >> > I have been considering. Please let me know what you think.
>> >> >
>> >> > Earlier this year I purchased a 160 sloper from Jim (KJ4WAS)
>> >> but have
>> >> > not installed it yet for a couple reasons. First, I needed
>> >> to get
>> >> > everything together to do the install and Secondly, I needed
>> >> to wait for
>> >> > the leaves clear off of the tree that seems to be the best
>> >> candidate for
>> >> > the installation. Lastly, having two back surgeries in a
>> >> single year
>> >> > have limited my ability to get it done.
>> >> >
>> >> > A couple things have been ringing in my head as possible
>> >> issues so when
>> >> > my launcher failed (line broke and I lost the weight on
>> >> launch) last
>> >> > night I was not too heart broken.
>> >> >
>> >> > Possible Issues:
>> >> >
>> >> > 1) Between my house and the tree in which I would like to do
>> >> the install
>> >> > is my vertical antenna and radial field. I have been
>> >> considering the
>> >> > effects that could be caused by running the new feed-line
>> >> either over or
>> >> > under the existing radial field.
>> >> >
>> >> > 2) The tree in which I would like to do the install is ~60ft
>> >> tall and
>> >> > greater than 100ft from the house so I am seeing that I am
>> >> going to need
>> >> > ~200ft of coax (which I already have) the thing that I have
>> >> been
>> >> > considering is if I should leave the feed-line as one piece
>> >> or put in an
>> >> > in-line adapter at the base of the tree.
>> >> >
>> >> > My current thinking is that Issue #1 is going to be the
>> >> bigger issue. So
>> >> > much so that I might need to consider a different tree or
>> >> would be
>> >> > inclined to move the vertical antenna to another part of the
>> >> back yard.
>> >> > Which for anyone who has installed a vertical would know how
>> >> much of a
>> >> > pain that would be especially with buried radials, coax and
>> >> an 8ft
>> >> > galvanized pipe driven in the ground as the base.
>> >> >
>> >> > For Issue #2 I am thinking of just leaving the coax as a
>> >> single piece to
>> >> > avoid any possibility of water getting into the connectors.
>> >> The losses
>> >> > for the coax at 200ft is only ~0.66 db on 40m to ~1.76db at
>> >> 6m based on
>> >> > JefaTech's Website and based on needing the full 200ft of
>> >> LL400 so the
>> >> > distance is not that big of an issue.
>> >> >
>> >> > Any thoughts?
>> >> >
>> >> >
>> >> > Thanks,
>> >> > Dan Metcalf -- KB3UUN
>> >> >
>> >> >
>> >> ______________________________________________________________
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>> >> >
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>> >>
>> >> > Message delivered to merc669 at gmail.com
>> >>
>> >>
>> >>
>> >> --
>> >> KC3DEZ
>> >> www.qrz.com
>> >> ______________________________________________________________
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>> >>
>> >>
>> >
>> >
>>
>>
>>
>> --
>> KC3DEZ
>> www.qrz.com
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>>
>
>
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