[SMCARA] Antenna Setup
Rene Ramirez
w3bnyren at gmail.com
Tue Nov 25 10:55:04 EST 2014
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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> >>
> >>
> >>
> >> --
> >> KC3DEZ
> >> www.qrz.com
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> >>
> >
> >
>
>
>
> --
> KC3DEZ
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