Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Portable Masts  (Read 1946 times)
KD4KNR
Member

Posts: 32




Ignore
« on: July 25, 2004, 10:45:28 AM »

I'm looking for ideas to build/buy a 20-30ft portable mast to support a ground plane antenna for emergency use... I've heard about using 2 inch PVC pipe. Any other suggestions??

Steve KD4KNR
Logged
KC8NIM
Member

Posts: 8




Ignore
« Reply #1 on: July 25, 2004, 06:07:37 PM »

Just found this in the 2004 dayton photos... pretty slick if you ask me. Looks like a teloscoping aluminum pole used by window washers or maybe painters.
http://www.eham.net/libraries/showfilepage/330?offset=18
If the link doesn't work its the second page of the photos and the bottom right.
                                  Eric
Logged
KG6OBC
Member

Posts: 28




Ignore
« Reply #2 on: July 25, 2004, 09:32:34 PM »

thats cart looks like its ready for some off-roadin (note the wheels).

i got my 440mhz jpole on the end of a golf ball retriver i got form a family friend. i cut one section off that had the scoop for the golf ball. it works great for that antenna. it's working quite well for my purpose. i think the length of mine after i cut the one section off was about 17' little shorter than what your lookin for but just a thought.

73,
KG6OBC
Justin
Logged
KE4SKY
Member

Posts: 1045


WWW

Ignore
« Reply #3 on: July 26, 2004, 01:31:36 PM »

IF you go higher than about 10-15 ft. with PVC you will probably find it too flexible for anything more than a simple 1/4 wave ground plane on 2 meters, if there is any wind.

An arrangement I have used with good success is a 3 ft. "Easy-Up" TV roof tripod and four 5 ft. sections of metal TV mast.  Anchor the TV roof tripod to the ground with landscaping spikes.  This will handle an antenna the size of a Diamond X50 at 20 ft. with no problem.

For larger antennas or great heights than 20 ft. I'd look for one of the military portable mast kits.
Logged
KD5JFT
Member

Posts: 82




Ignore
« Reply #4 on: July 27, 2004, 03:49:26 PM »

What I use:

Speaker tripod (got it on sale at a music store for less than $50.00).  This is the kind of tripod they use for large speakers at concerts and stuff.

Several steel tv antenna masts.  I use either 5ft or 10ft depending on where I'm going.  I have used three 10ft and the tripod to get very near 40ft up.  I usually use 3 or 4 5ft masts since my pickup bed is only 6ft long (they fit neater).

Hose clamp and D rings.  For attaching guy ropes.

Parachute cord.  For guys.  Temporary use only!!  

Three spiral ground stakes for the other end of the guys.

Antenna of your choice.  Keep it small since this is not a very strong setup.  I use either a tri-band (6M/2M/70cm) vertical or a dual (2M/70cm) band 3 element beam with a channel master rotor.  I also have used it with omni horizontal 2M and 6M antennas.  I eventually intend to get something along the lines of a 50MHz to 500MHz log periodic.  They look like they will work quite well on this.

This can be installed by one person, but is much easier and safer with two or even three people.  Four people make it a snap to setup in minutes.  More than four and the beer disappears quicker as people stand around and watch.

I am only a lowly no-code tech with a FT-847 and a FT-726R so I limited my portable setup to 6M and above.  It is real fun to take this to the state parks and lakes.  Usually get some good attention from other campers and the rangers.  Some of the rangers were hams and came over after shift or during breaks (or even on duty) to operate.  We all have fun (the main reason) and generate some small interest in ham radio.  I can get out reliably over 100 miles without a band opening.  Nice to be able to talk simplex into two or three major cities in an area where cell phone service is non-existant.  Good practice for emergency use.
Logged
AC7KT
Member

Posts: 11




Ignore
« Reply #5 on: July 28, 2004, 02:20:30 AM »

The pole in the pictures is a Stetcone ettore if I got the name right found at Home Depot and other stores. Used for window washing and other things.Try finding a Unger Tele Pole much better quality costs more too I have 3 4,8,13 foot poles.

73's
AC7KT
Lee
Logged
K1CJS
Member

Posts: 6055




Ignore
« Reply #6 on: August 03, 2004, 07:30:52 PM »

I also use the 5 ft. mast sections.  I have 4 in my car and a small toolbox with guy straps/ropes and stakes to support the setup.  It takes me about 20 minutes to put up a servicable antenna with that setup.
Logged
K2GW
Member

Posts: 535


WWW

Ignore
« Reply #7 on: August 11, 2004, 05:11:46 PM »

I‘ve used a number of portable masts for emergency VHF communications antennas.  The first type consists of six five foot lengths of TV mast with a Larsen mobile antenna adaptor hose-clamped to the top.  This works well but is very heavy.  If you’re going to use all six sections (30 feet), it needs to be guyed at the top and middle with parachute cord. Hose clamps and D rings provide attachment points for the guylines.

If you only want to use four sections (20feet), you can use a Radio Shack roof tripod as a base and avoid guylines.  If you make a base frame for the tripod out of two by fours with carriage bolts and wing nuts for the tripod holes, you can weigh it down with sandbags on paved surfaces where you can’t use stakes for guy anchors.  A side section with a plywood base allows a vehicle to drive on and weigh it if you wish.

The TV mast sections and mobile antenna can be stored in a ski bag.  Use two six inch PVC pipe caps at the ends to keep the mast sections from punching through the nylon bag.

Although it’s cheap and strong, the disadvantage of using TV mast is weight.  Weight makes it hard to carry, erect and guy.  It's also still five feet long collapsed.  As a result, my TV mast kits mostly get used to support HF antennas at Field Day.

Recently, I’ve been using the 30 foot DK9SQ carbon fiber mast to hang a rollup J-pole or support the folding DK9SQ 144/220/440 log-periodic at the top.  The mast can also simultaneously support NVIS inverted vees for 40 and 80 meters at the fifteen foot level.  The whole setup weighs less than five pounds and can thus be Velcro strapped to nearly any vertical object or a vehicle side mirror.  This can be found at http://www.w0ipl.com/ECom/NVIS/K2GW-NVIS.htm

Also the commercial Buddipole system can be used as J-pole on two meters and 440.  Info on it can be found at www.buddipole.com   I use this setup alot for general portable work.

73

Gary, K2GW
SNJ SEC









Logged
AI4DG
Member

Posts: 18




Ignore
« Reply #8 on: August 16, 2004, 02:55:25 PM »

I have used PVC pipe before at a disaster site.  I think it was a 1.5" and a 2" section telescoped.  I used clear packing tape to join the sections and mount it on an external stairwell.  I ran coax up the middle of the pipe to the 2 meter ground plane.  It did the job and cost all of $10 at any hardware store.  Getting the RF outside and above the roofline does wonders.  It held up to some post-storm winds.

What's really important about this setup is that except for the coax, which wasn't mine, I didn't care about getting any of this equipment back.  It sat at the site for weeks and I didn't worry about it.  

If you have ever had to set up a disaster site every morning with different equipment, you can really appreciate the idea of a "leave behind" setup, even if it's just the antenna system.
Logged
KD4KNR
Member

Posts: 32




Ignore
« Reply #9 on: August 16, 2004, 03:03:52 PM »

AI4DG,

How high could you go with the PVC?
Logged
KD4KNR
Member

Posts: 32




Ignore
« Reply #10 on: August 16, 2004, 03:05:16 PM »

AI4DG,

How high could you go with the PVC?
Logged
AI4DG
Member

Posts: 18




Ignore
« Reply #11 on: August 16, 2004, 09:13:21 PM »

I've easily gone two sections.  I think they came in 10' lengths if I remember, and with the overlap, it probably gave me about 18 feet.  But since I could put it on a stairwell railing near the top of the second floor, I got a good 30-35 feet up.  The important thing was that 18 feet got me above the roofline.

You could possibly get three sections together, but you might have to go way above the 2" size for strength.  I've actually seen a 30-40 foot flagpole made from PVC drainpipe, maybe 6" or 8" at the base.  It was quite wobbly, but was a permanent installation for a while.

A handy alternative is a Walmart golfball retriever.  It's a 15' aluminum pole that telescopes down to a bit over 4'.  $9.98 at Walmart.  Lash that onto a railing, signpost (like a handicapped parking sign), or fencepost and you could easily be 20 or 25  feet in the air.  Just lean it against a building and you'd be above the roofline.  It's sturdy enough to support a groundplane or possibly a copper pipe JPole (if you didn't extend it all the way at the top).  It might not take the weight of that much RG-8 sized coax, but RG-58 would be fine.  It's a good piece to pack when you have to deploy with limited cargo space, or something to keep in your trunk.
Logged
WV2NY
Member

Posts: 10


WWW

Ignore
« Reply #12 on: August 20, 2004, 05:03:22 PM »

I like to use the top railing for chain link fencing.  Sold in ten foot lengths and tappered on one end so they can fit together.  They usually sell for around $8 a section and are found in most hardware stores.  I currently have my 2m antenna mounted on two of these out back.  They get a bit wobbly when mounted higher than 3 sections, 30'.  Quick, easy and cheap.

WV2NY
73  JOE
Logged
K4TMC
Member

Posts: 3




Ignore
« Reply #13 on: August 29, 2004, 01:18:36 PM »

Steve,

Check the mast items at www.TMastCo.com.

Henry -K4TMC
www.TMastCo.com
Logged
KE5BCG
Member

Posts: 39




Ignore
« Reply #14 on: September 14, 2004, 01:19:03 PM »

Are you stuck on 30 feet? If not you might consider window-washer poles. I saw one at Home Depot in the janitorial area that was collapsable to 10 feet. It seemed pretty stout for a mobile antenna mount and could easily be guyed with the addition of lines.
Pete
KE5BCG
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!