Just FYI, the RF Connection in Gaithersburg MD is a good source for used 1/2"
hardline connectors. They come simply lopped off the ends of the cable they
were on, so you can "reverse engineer" how they are installed, and once you see
it, it's VERY simple. These connectors are N females, but they are a lot
cheaper and more plentiful that UHFs for 1/2 inch line.
If you're interested in homebrewing your own UHF females for 3/4" TV hardline,
check the Towertalk archives for a message from W4AN (SK) that explains how to
do it with an Amphenol barrel connector and a $2 plumbing adapter. For HF, the
half-wave multiple idea worked fine for me here from 160 to 10 meters, without
matching transformers. I cut the feedline to be a multiple of a half-wave at
1750 KHz, and then measured and trimmed the length at 28 MHz.
73, Pete N4ZR
At 10:46 AM 2/23/2007, Dan Hearn wrote:
>Wendell, you definitely need hardline or your losses will be severe. It can
>be buried without PVC cover. I have bought lots of Andrews 1/2 and 7/8 used
>at the Hamcom convention in Dallas when I lived there. Your problem will be
>finding long enough runs and you might want to have surface boxes along the
>way to use the available lengths and connect them. You could use 75 ohm TV
>stuff and possibly 75 to 50 ohm ferrite xfmrs for the hf bands. I would
>think seriously about putting the vhf/uhf stuff nearby the house. It is good
>if the used hardline has connectors on it but it is easy to fab your own
>with copper tubing parts. You might contact some of the guys in the North
>Texas Contest Club for cable sources 73, Dan, N5AR
>
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com]On Behalf Of Wendell Wyly -
>W5FL
>Sent: Thursday, February 22, 2007 9:12 PM
>To: Towertalk@Contesting. Com
>Subject: [TowerTalk] Help on new Tower installation planning and
>Feedlines
>
>
>My interests are a small station contester and a dxer and have been
>doing this since 1955. Appreciate any suggestions on planning for my
>new tower installation to be put in next month. Budget is approx
>$2000. Distance from Transceiver to tower site is 375 feet. Tower
>elevation is approx 35 feet above house and Tower is a used 64 foot
>Rohn 45 Foldover tower taken down from my last house two years ago
>and to be put back up to Rohn Specifications using the original guy
>lines and 4 guy posts and 2 el cubical quad 5 band antenna and rotator.
>
>All wire and conduit is new. Plan to have two HF feedlines and one
>144/440 VHF feedline and 8 cond rotor cable for Hy Gain T2X Rotor and
>a 4 or more small gauge (#24) wires to control the antenna switching
>for 80,40 dipoles and 10/12/15/17 and 20 meter 2 el quad loops or
>maybe a better antenna. Plan to use 360 foot 1 1/2 or 2 inch pvc
>conduit for the feedlines and 3/4 or 1 inch pvc conduit for the
>control lines to be buried about 12 to 18 inches.
>
>Budget is kinda skimpy but always wanted to use 1/2 inch hardline due
>to low loss, but don't know if it pulls through conduit ok. Trade
>off is LMR 400 or LMR600 or ???. The conduit run is 140 feet to a
>pull box and then 220 feet for a total of 360 feet. 1500 Watts on
>HF and 50 Watts on 144/440 VHF. Looking at using preamp or two band
>amp/preamp on tower for 144/440 vhf due to long coax run, but unsure
>what kind works well and particularly how to power it through the
>conduit run from the house.
>
>Is direct burial coax any better or worse than LMR type or hardline
>in pvc conduit? Soil is both sandy and rocky. The site is rural and
>ups is preferred to truck shipments, so how do they ship hardline so
>it does not get damaged or it is worth fooling with for this
>installation?
>
>Have never had any coax lightning arrestors, but was considering
>putting them on the coax lines and control lines at the house single
>point ground entry panel if I can find a reasonable cost solution and
>ground the coaxes at the tower base. The house has both lightning
>rods and a good perimeter grounding system.
>
>ANY and ALL suggestions and comments will be sincerely appreciated as
>will suggestions to keep the total costs of materials as low as
>practical.
>_______________________________________________
>
>
>
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>
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>
>
>
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