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Survivalism & Self Sufficiency Topics => The HAM Radio Board => Amateur Radio How-To's => Topic started by: Carl on May 15, 2014, 01:53:06 PM

Title: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on May 15, 2014, 01:53:06 PM
This antenna have been used a club projects for some time and is easy to build with a solder iron and little skill can give good results . As it is PVC and has no radials, a eye hook on top allows a rope to get it well up a tree for good capability and range. Fist big TIP,if hung by rope ,don't just tie a rope to the top and pull....allow some of the rope to support the coax and help prevent damage from weight stretching it and causing problems.Keep close measure on the wire and there will be little need to worry about SWR. This antenna is SHUNT FED and therefor "looks" like a short on an ohm meter,but it matches well and has low static and noise due to the shunt.

  Good coax,a bit of ladder line and some left over 13 to 14 ga stranded wire ,plus PVC 1" and Cap are about all you will need.
I like best the RG-8X ,slightly larger than RG-58 and better shielded, for low loss...but most any coax will do.

  The plans are on my Google drive and accessible by anyone with the link,my intent is to SHARE them freely.

PDF   https://drive.google.com/file/d/0B5ZIZLZV4AwIVVVPNGJiODFjM0U/edit?usp=sharing

OR as WORD document   https://drive.google.com/file/d/0B5ZIZLZV4AwIbzY3MjZiSkg0S0U/edit?usp=sharing
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Smurf Hunter on May 15, 2014, 11:11:58 PM
Carl,

Thanks for sharing.  I'm a total newbie - having passed my general last Tuesday.  Can you comment on how or if this design would work differently from this:

http://www.2wayelectronix.com/Vhf-Slim-Jim-Antenna-with-16-rg-58-vhf-slim-16.htm (http://www.2wayelectronix.com/Vhf-Slim-Jim-Antenna-with-16-rg-58-vhf-slim-16.htm)
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: redeyeprep on May 16, 2014, 04:23:32 AM
Carl,

Thanks for sharing.  I'm a total newbie - having passed my general last Tuesday.  Can you comment on how or if this design would work differently from this:

http://www.2wayelectronix.com/Vhf-Slim-Jim-Antenna-with-16-rg-58-vhf-slim-16.htm (http://www.2wayelectronix.com/Vhf-Slim-Jim-Antenna-with-16-rg-58-vhf-slim-16.htm)

They're both J-Pole antennas and would have quite similar performance. Ladder line antennas can also be rolled up, which makes them ideal for go bags.   :)
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on May 16, 2014, 07:13:22 AM
They are of similar initial design
  BUT the Big Stick is RIGID ,as it is PVC encased, and will stand on it's own.
  The PVC also weather protects the antenna and gives it better protection for a more permanent antenna installation. PLUS loses little portability due to the small size , though the wire only version is much the same as the one in the link.

BIG PLUS...You make this one yourself..
AND you can make the WIRE ONLY version of the big stick,though dimensions change due to the fact that the PVC actually RADIATES RF (few know that PVC is somewhat conductive to RF) The measurements for wire only are in my poorly written instructions.

  The big stick is a model of a zep antenna, it is a half wave over a quarter wave matching stub and though it has GAIN...that is not much of an issue with VHF/UHF antennas where HEIGHT above terrain is your primary limiting factor.

I don't sell, I freely give these plans away . If you want to get quality and satisfaction , BUILD ONE.

For a GO BAG ,the roll-up version is OK,but will not survive the stress of daily use for long..What are you going to GO in that a 5 to 6 foot piece of PVC will not fit in,or on,also?If you are going to where communications is NEEDED...I think it better to take something substantial enough to RELY ON.

I get upset when HAMS ,who are held high because they have technical ability,want to purchase such simple to make items...forgive me as this was not a personal attack. But aren't WE ,as HAMs and survivalists...more about SKILL and standing tall on our own feet??
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Smurf Hunter on May 16, 2014, 07:59:18 AM
I'm headed out on a weekend camping trip with my kids this afternoon, but this might be a memorial weekend project.  I'm starting from zero.
I don't even have any 50ohm coax or PL259 end pieces.

Do most HAMs order spools of coax online, or is that something you can reliably get locally?
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: redeyeprep on May 16, 2014, 10:36:00 AM
They are of similar initial design
  BUT the Big Stick is RIGID ,as it is PVC encased, and will stand on it's own.
  The PVC also weather protects the antenna and gives it better protection for a more permanent antenna installation. PLUS loses little portability due to the small size , though the wire only version is much the same as the one in the link.

BIG PLUS...You make this one yourself..
AND you can make the WIRE ONLY version of the big stick,though dimensions change due to the fact that the PVC actually RADIATES RF (few know that PVC is somewhat conductive to RF) The measurements for wire only are in my poorly written instructions.

  The big stick is a model of a zep antenna, it is a half wave over a quarter wave matching stub and though it has GAIN...that is not much of an issue with VHF/UHF antennas where HEIGHT above terrain is your primary limiting factor.

I don't sell, I freely give these plans away . If you want to get quality and satisfaction , BUILD ONE.

For a GO BAG ,the roll-up version is OK,but will not survive the stress of daily use for long..What are you going to GO in that a 5 to 6 foot piece of PVC will not fit in,or on,also?If you are going to where communications is NEEDED...I think it better to take something substantial enough to RELY ON.

I get upset when HAMS ,who are held high because they have technical ability,want to purchase such simple to make items...forgive me as this was not a personal attack. But aren't WE ,as HAMs and survivalists...more about SKILL and standing tall on our own feet??

No offense taken. I agree with you 100% that it’s ridiculous to buy something that you could just as easily make yourself. In fact, I consider antenna projects to be one of the easiest ways for a new Ham to get their feet wet, and to build something with a reasonably good chance of success right out of the gate.

Another thought occurs to me, though I’d have to look through your plans again to ascertain the practically: what if you made a portable version of your PVC version? Saw the PVC in half (or even thirds) and cement a pipe coupling to one end of the pipe (or pipes). Then you could break it down for easy transport (because a six foot length of PVC could be a little awkward in some circumstances). I’ve made temporary masts – short masts obviously – this way, and it works pretty well. I’m thinking you could even leave the antenna inside, and simply fold it at the joints. Obviously, a single piece of PVC would be far better for a permanent installation, but the folding version would make a nice field portable antenna.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Alan Georges on May 16, 2014, 11:58:16 AM
Do most HAMs order spools of coax online, or is that something you can reliably get locally?
I lucked into a short spool of RG-58 a year ago for, dunno, $35?  $50?   One 120' run, one 60' run, and one more 70' run to go, I'll still have a little left over.  Connectors are cheap at ham shows too.

On VHF, I'm using LMR-400.  It uses a slightly different type connector (still PL-259, just different to connect to the coax), so instead of DIY in that one case I just bought a pre-made cable.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Alan Georges on May 16, 2014, 12:04:46 PM
I get upset when HAMS ,who are held high because they have technical ability,want to purchase such simple to make items...forgive me as this was not a personal attack. But aren't WE ,as HAMs and survivalists...more about SKILL and standing tall on our own feet??

As with redeyeprep, no offense taken, even though I went a different route this time with a pre-made 2m antenna.  It was just a matter of finding the time... sometime, or getting a 2m capability in, tested, and working before hurricane season starts.  The roll-up slim jim for the go-box will definitely be a home-brew.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Smurf Hunter on May 16, 2014, 12:48:05 PM
Aside from bad or no reception, what's the risk of a DIY antenna in general?  I've read that if you power up a radio without antenna connected it can actually cause damage to the transceiver.  Is this where "dummy loads" come into play?
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on May 16, 2014, 04:25:32 PM
Replying in no particular order , I began to answer some questions:

Most important first,you don't need an antenna to LISTEN...well on two meters 19 inches of wire will do to listen...BUT to transmit you must have a properly designed antenna.

  A good inexpensive mag mount ,with cable and ready tuned is here:   http://www.amazon.com/Tram-1185-Amateur-Dual-Band-Antenna/dp/B0045EQUBK/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1400277741&sr=1-1-catcorr&keywords=ham+magnetic+dual+band+antenna

  While a pretty good one for UV5 /UV82 users is here  http://www.amazon.com/Nagoya-UT-108-430MHz-SMA-Female-Antenna/dp/B00F3SJ8NO/ref=sr_1_45?s=sporting-goods&ie=UTF8&qid=1400277642&sr=1-45&keywords=ham+antenna

 A good source for quality coax is the RG8X (called MINI 8) low loss,by the roll or pre-made length is here at R and L electronics:  http://www.randl.com/shop/catalog/index.php?cPath=11030  It need a different INSERT than RG 58 as it is a bit larger diameter.

And for the 'do it yourselfer' I have used the old flat TV cable,12 to 14 gauge SOLID wire simply BENT to the right shape and size. Also I have used FLAT speaker wire in a pinch.But if you use good ladder line,the measurements will work..if you have access to an ANALYZER or VHF -SWR meter then you are free to experiment. Follow my supplies listed and odds are you will be able to build it without test equipment or adjustment needed.


Pre-Made is OK...I started with some myself. But over 80 big sticks are in use in my area,most built by me as most people just hit the EASY BUTTON and may never know the satisfaction (and FREEDOM) of knowing how to do it yourself.

LMR400 is GREAT coax, but I am buget minded and the MINI-8 linked above has proven to be as good ,or better than average RG-8 PLUS I have some that has been in the weather with as much as 1200 watts (VHF POWER!) and it still looks and tests good after over 25 years of use. USE GOOD sealing tape for you connectors and you will keep water out of your coax.

Hopefully I did not mispel to many werds..
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: SCWolverine on May 17, 2014, 04:38:12 AM
EZ button guy here:  (http://www.animated-smileys.com/emoticons/animated-smileys-waving-002.gif)

I've had great success with a very similar designs purchased from Ed Fong for 2m/440 and 220.
http://www.ebay.com/sch/antennas_iqn/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686 (http://www.ebay.com/sch/antennas_iqn/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686)

If you have the time and desire, build one...if you're busy with your 5 kids-buy one  :)

I did recently build a similar (vert dipole in PVC) FM transmitting antenna for a small Part15 Transmitter.

The N9TAX slim-jim is an excellent antenna as well, mine has served many roles...good quality for both mentioned.

SCW
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on May 17, 2014, 06:14:39 AM

Another thought occurs to me, though I’d have to look through your plans again to ascertain the practically: what if you made a portable version of your PVC version? Obviously, a single piece of PVC would be far better for a permanent installation, but the folding version would make a nice field portable antenna.
[/quote]

You can use a bit of shock cord and two-piece it fine,or just use an expanding whip to replace part or all of the top wire above the matching stub.It can be made about two feet long with the 'whip' method .

I have built the antenna where the TOP (above the matching stub) was made from part of a measuring tape (from 99 cent store and they also worked fine untill winds would alter the 'verticleness' of the unit.

I used a short piece of ladder line for ECONOMY,the added wire was a cost cutting move ,NOT a design, I have built the antenna in many forms but changes from the measurements REQUIRE an SWR meter or ANALYZER as deviations of as little as 1/8 inch ,on the short side and 11 inch on the long side can move the antenna resonance completely out of the HAM bands.

  Don't be afraid to alter my plans,have FUN with it...BUT if built with materials and measurements I listed...it can be trusted as correct (and thus radio Friendly) without the need for specialized test equipment.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on May 17, 2014, 06:21:21 AM
As I re-read and saw (HORROR) the long side must be cut within ONE INCH to be in the HAM band ...not 11 .
  I am replacing this keyboard NOW as it is just to out of spec..
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Alan Georges on May 17, 2014, 06:42:31 AM
Aside from bad or no reception, what's the risk of a DIY antenna in general?  I've read that if you power up a radio without antenna connected it can actually cause damage to the transceiver.  Is this where "dummy loads" come into play?
The specific risk is that the antenna isn't resonant at the frequency you're using, and will reflect significant power back down the feed line (i.e., high SWR) and fry your amplifier circuits.  Having said that, for a robust DIY design (that is, tolerant of small fabrication variations) the odds of this happening are small, and as an added measure of safety many newer transceivers can detect this and shut down before they burn out.  Still, put an SWR meter on the thing before you crank up the power.

Nah, dummy loads are more used for tuning up a radio or maybe diagnosing a feed line problem.  A DL just presents a rock steady 50 ohm load "power dump" to whatever's feeding into it, so that you can jack around with your transceiver without lighting up the neighborhood.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on January 03, 2015, 09:03:52 AM
 8)  This should be available for winter projects time.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: SCWolverine on March 05, 2015, 05:08:51 AM
The boys and I built a "Big Stick" yesterday-following Carl's PDF.  I only had Gray PVC on hand so that's what I used.  Upon completion-I know now why it's called the "Big Stick" (It's Big) on the outside  ;)
Anyways, I built for APRS use and tested on a near freq to 144.390 with a resulting SWR of 1.6, it looked great on my local 2m repeater freq as well-good signal reports too.
Thanks Carl, need to build a few more of these while I have the stuff laying around!
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on March 05, 2015, 05:44:48 AM
The boys and I built a "Big Stick" yesterday-following Carl's PDF.  I only had Gray PVC on hand so that's what I used.  Upon completion-I know now why it's called the "Big Stick" (It's Big) on the outside  ;)
Anyways, I built for APRS use and tested on a near freq to 144.390 with a resulting SWR of 1.6, it looked great on my local 2m repeater freq as well-good signal reports too.
Thanks Carl, need to build a few more of these while I have the stuff laying around!

Glad to hear the BIG STICK is finding usefulness.I first worked up the simple design to be effective and easily repeatable. It will benefit from a couple of snap on ferrite beads or common mode choke as the coax shield does support a bit of RF. And note that the PVC actually is part of the radiator and not the insulator most would believe.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: SCWolverine on March 05, 2015, 06:16:20 AM
wondering if the lesser PVC (name and PSI escape me) would work as well?  It's more of a thin-wall design? 

thanks again Carl
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on March 05, 2015, 06:27:15 AM
wondering if the lesser PVC (name and PSI escape me) would work as well?  It's more of a thin-wall design? 

thanks again Carl

Yes,I have always used the slightly heavier WHITE PVC,but the thin wall also works well...just not the best for protection from the forces of man and nature.The BIG STICK was designed as a permanent or temporary antenna that could be pulled up into a tree(with some rope to support antenna AND coax) ride the stake hole of a pick-up truck,or ride in a truck bed full of junk and survive. The bottom area is just to support the antenna and attach with screws.nails,duct tape to most any makeshift support.
I even used one for a push pole ,to maneuver a boat,and then stood it atop a building to support cross-band duty .


Just be careful...they tend to get borrowed as fast as I can build them.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: TiredOldGrunt on March 05, 2015, 03:54:39 PM
An SWR/Watt meter is needed to properly tune it, as is with any HB antenna.

TOG
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on March 05, 2015, 04:11:41 PM
An SWR/Watt meter is needed to properly tune it, as is with any HB antenna.

TOG

That is a good idea,I should tell people to check it so they don't damage their radios....Thanks Grunt.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Greekman on October 03, 2015, 12:18:21 PM
hmmmm. I know that the PVC pipe affects antenna tuning and I believe Carl has taken it into account.
But what happens when one changes PVC pipe dimensions.
We have a different standard over here and i *think* we categorize p[ipes by the outside diameter
Carl are you using 1 inch outside or inside diameter pipe? Schedule 40?
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Carl on October 03, 2015, 01:49:17 PM
hmmmm. I know that the PVC pipe affects antenna tuning and I believe Carl has taken it into account.
But what happens when one changes PVC pipe dimensions.
We have a different standard over here and i *think* we categorize p[ipes by the outside diameter
Carl are you using 1 inch outside or inside diameter pipe? Schedule 40?

While it 'slightly' effects radiation ,I use 1 inch ID pipe and use schedule 40 most often...but lighter weight PVC pipe has also worked well with length enough to fit the antenna within and some were just longer than the wire antenna (for hanging by rope from a tree) while others used the entire 10 foot stick of PVC pipe...the only 'problems' were had with GREY PVC as it is more conductive...so I would stick to using 'WHITE PVC' as it is less conductive...I did build one BIG STICK with clear plastic pipe and it was to demonstrate the construction....but it also works fine for 2 meters ...but not so good with reaction to UV rays that often cause plastic to decompose.
Title: Re: The BIG STICK , easy to build VHF UHF HAM Antenna
Post by: Greekman on October 03, 2015, 03:54:10 PM
thanks for the pipe quality note...