[HCARC] What To Run To THe Shack For Feedlines

Fri Nov 23 09:46:09 EST 2012

Dale,

I have run conduit before - 2 1/2 inch from my power pole to my in house 
electrical service which goes under my slab.  Pulling that was not fun with 
BIG COPPER Lines (4 each - 2 hot, 1 return and a ground), so I am very 
familiar with pulling them section by section.  The current gray conduit is 
already cemented together so I will first cut it to usable lenghs and then 
recouple it together.  I am not sure of the type of switch yet (probably one 
of the MFJ 5 or 8 position switches) so I guess I should plan on an 
electrical cable in the pipe just to be safe and have electricity on the 
hill for if nothing else "future use".   I might as well do it while the 
"trench is open".  Can the electrical cable go in the same conduit or will 
it cause interference or act like an antenna??

I have Jerry Sevick's Balun book and it seems more confusing than helpful at 
this point.  It would be nice to just have a small book of do this for an 
Unun  and that for a 4:1 Balun and this for this size Balun and this for a 
choke and so forth.  It seems to be an area where Ham's could get their feet 
wet with HOMEBREWING, yet it remains such a mystery.  It's why I suggested a 
class in Unun and Balun building and for the club to run a mini-store of 
commonly needed Radio related parts.  It would be differrent if we had a 
radio store within easy driving distance, but Austin is a wee bit far.

Good idea about the weather heads.  I will plan for that at least on the 
antenna end of the run.

Cat 5 cable is the direct bury kind.

Gary J
N5BAA
HCARC Secretary (2013)

----- Original Message ----- 
From: "Dale Gaudier" <dale.gaudier at windstream.net>
To: "'Gary and Arlene Johnson'" <qltfnish at omniglobal.net>
Sent: Thursday, November 22, 2012 11:12 PM
Subject: RE: [HCARC] What To Run To THe Shack For Feedlines

> Gary:
>
> Use coax for your underground run. As Kerry has already pointed out 
> balanced
> line won't work. Use one run of a high quality "buriable" type of coax - 
> it
> has a heavy duty jacket that resists deterioration and water penetration.
> Put in a "pull line" (1/16" galvanized cable) with your coax to facilitate
> pulling replacement/additional cable at some future date. 2" PVC EMT is a
> good choice for the cable conduit.
>
> What type of remote coax switch are you planning to use? Some types use 
> the
> coax itself to conduct the power and switching signals to the coax switch,
> others require a separate cable to do this. If you use the latter, you'll
> need to include the control line with the coax when you lay the cables.
>
> Don't forget to include lightning protection for the coax and any 
> switching
> cable.
>
> When you lay the cable, don't make the mistake of cementing all the 
> conduit
> sections first, then trying to pull the cable(s) afterwards - it can be
> done, but it is a lot simpler to feed the cable(s) one section at a time,
> cement the PVC joints after the cable has been completely fed through all
> the conduit, then drop the conduit into your trench. Also, consider how 
> you
> will bring the conduit out of the ground at both ends. At my QTH, with a
> 200+ foot underground run, I used PVC "weather heads" that are used for
> electrical service entrances - they help to keep rain and critters out of
> the conduit.
>
> BTW, the topic of ununs and baluns has been made to seem very complex and
> there is a lot of misinformation about when to use them and how they work.
> The seminal book on the topic is Jerry Sevick's "Understanding, Building 
> and
> Using Baluns and Ununs". It is a practical guide to building baluns and
> ununs, and when each is appropriate for use. You can purchase a copy here:
> http://www.dxengineering.com/search/department/books-and-publications/produc
> t-line/cq-communications-understanding-building-and-using-baluns-and-ununs?a
> utoview=SKU
>
> FWIW, in most cases, where you only want to go from a balanced antenna 
> (e.g.
> dipole) to unbalanced transmission line (coax), you don't need a "real"
> balun - just an RF choke to prevent the unbalanced current that results 
> from
> going from a balanced to an unbalanced condition from flowing on the 
> outside
> (shield) of the coax. Here's a link to instructions for building a simple 
> RF
> choke from coiled coax: http://www.hamuniverse.com/balun.html  I use these
> extensively for my antennas and they work. Note, however, if you need to
> transform impedances you'll need a real balun - these can be of the 
> toroidal
> variety or built from appropriate lengths of coaxial transmission line. I
> wouldn't bother with trying to match/transform impedances unless the
> mismatch is greater than 2:1 - you won't notice it in transmitting or
> receiving and the tuner in your K3 will easily handle the slight mismatch.
>
> Hope this helps. Come and visit me sometime and you will see how I handled
> the laying of underground conduit ay my QTH and my collection of baluns 
> and
> RF chokes.
>
> 73,
>
> Dale - K4DG
>
> PS: You mention running CAT5 line for your internet connection. If you do
> this, be sure you use cable that is certified for outdoor use, otherwise
> you'll be replacing the cable after only a few years. Note that CAT5 cable
> is normally limited to a maximum unamplified run of 100 meters (330 ft.) 
> so
> be sure your actual cable run (router to PC) is less than this. Or do as I
> did and get an amplified directional WiFi antenna to hook up to your PC or
> router. Mine works over a path of 300+ feet from my house to my hamshack 
> and
> cost about as much as the equivalent length of outdoor CAT5 cable.
>
>
> -----Original Message-----
> From: Gary and Arlene Johnson [mailto:qltfnish at omniglobal.net]
> Sent: Thursday, November 22, 2012 11:06 AM
> To: Hcarc at mailman.qth.net
> Subject: [HCARC] What To Run To THe Shack For Feedlines
>
> The center of the area I plan to put my antennas is approx 150 feet from 
> my
> shack.  I plan to run the antenna leadline to the shack underground in 2
> inch gray conduit.  My plans are to run 3 coax transmission lines in one
> conduit (one for use, 2 for backup) to a switching system out at the
> antennas so that only one transmission line at a time will be in use.  I
> have plenty of free conduit, so would it make sense to run a second 
> conduit
> out to the antennas with balanced feed lines in it or can the balanced 
> feed
> lines run in the same conduit as the Coax??  If I run two conduits, can 
> they
> be in the same ditch or do I need a second ditch??  Either is doable as I
> will be renting a ditchwitch for a weekend to get all of the lines buried 
> at
> one time - I have some other non radio related electrical lines to bury at
> the same time, as well as Cat 5 cable to run to bring internet to my shack
> and some water lines to bury.  Going to be a busy weekend when it happens.
>
> 73's and Happy Thanksgiving to all
>
> Gary J
> N5BAA
> HCARC Secretary (2013)
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