DIY HF whip

[GILow]

Hi all,

I really thought I had asked this question a while back, but if so, I cannot find the answer now. So my apologies if you answered already, and if so, can you point me to the thread?

I am looking at making a HF whip antenna for my boat. The sort of thing that I'd like is way out of my budget to buy, so DIY is the only option.

I have an ICOM HF radio with an AT130 tuner, currently connected to the backstay. But I'd like an option if the mast falls down. Paranoid, but hey, that's me.

I thought the theory would be simple for this one, a length of aluminium tube, some wire... but I really cannot get a handle on it.

Does anyone have experience with building this sort of thing who can give some tips, or point me to a web site that a mere mortal can understand. (Yeah, I know, I SHOULD understand all this from doing my license, but it was a few years ago and the theory is long gone.)

Matt

[Salty Possum]

The easiest thing to do would be to buy a mobile ham HF antenna, install it, then take it down and stash it below for such an emergency. If whatever took out you mast took out your tuner, a plan whip would have to be cut for the frequency of use, or otherwise tuned. Do you know what frequency that would be? A quarter wave whip without a loading coil for 14 MHz would be about 16 feet, for 7 MHz, about 32 feet—not very practical. The HAM market has some portable vertical antennas that you can put together when needed.

Would whatever took out your mast leave you with a dry functioning radio anyway? The least expensive backup option, perhaps more proportionate to the low likelihood of use, would be a wire half wave dipole cut to the expected frequency of use—then assume that you can get it at least a few feet above the deck with something. For the low bands, a lower antenna can be more effective anyway for area communications of a hundred miles or so than a higher antenna. Nothing beats the versatility of wire for emergency antennas. A copy of the ARRL publication on emergency and wire antennas in a zip lock bag is probably the best back up. I have always had better luck on the Ham bands with half backed homemade wires run horizontally than I have had with more elaborate vertical antennas.

With rudimentary antenna knowledge and wire or other metallic structures, you can always find something to radiate a signal. I know a ham who worked Cuba on a child’s swing set with the legs set in mason jars.

[Salty Possum]

Something interesting to try without waiting for an emergency would be to attach the AT 130 to a random wire the length of your boat run at the height of the rail but insulated at each end with glass jars, rubber bands, or whatever you have. Don’t let it touch metal. See what you can hear. If you can hear them, try to work them making sure no one is near enough to the antenna to get shocked.

[Brian.D]

23' is one of the optimal lengths for a vertical. You will attach it any way you can to the boat. Run the GTO15 from the tuner to the base of the antenna. The boat's counterpoise should be intact but if not, you can drop a wire about 6" into the water from the tuner's ground lug.

If built correctly, it should telescope into itself to save stowage space.

Check out this link https://g8jnj.webs.com/usingautotuners.htm

[RaymondR]

Get a piece of that blue lay flat hose and plug the ends with the valve stem out of a push bike rube in one end and run a wire up the inside of it. Inflate until sufficiently tumescent and stand on it's end, connect to transmitter and go for it.

[El Pinguino]

Buy a squid pole.... https://www.ebay.com.au/itm/HAM-Radi...EAAOSwZVlXqq3h take rubber bobble off top....run copper wire from tuner through deck gland to bottom of squidpole and then up its insides ..... duct tape end of wire at top of squid pole...... secure squid pole to taffrail with duct tape..... also tape the joints in the squidpole so it doesn't do whatever the opposite to telescope is.....
As purchased the squidpoles are about one metre long... extended you can buy from 6 to 10 metres in length.

Your tuner should have no problem tuning it.

Mine lasted some years before having a fatigue failure in way of the top of the taffrail. They can flex a fair bit so make sure it can't mate with the blades of your windgen.
My Tasmanian Moonraker did the same thing a few years later.... I just cropped 2 feet off the base of it... still works good.
First pic..... moonraker on boat....some time prior to this photo being taken... on a long sea voyage... the top half unwound and fell off one dark and stormy night.... you can see where they are joined.... tuner still tuned the stump just fine.
Second piccy.... squid pole on top of 2 inch pvc pipe with SEA tuner at base... down on the campo.

When my mast fell down I didn't have a squid pole .... built an A-frame out of 2 spin poles.... ran copper wire from aft over the top of A-frame to pulpit ...worked just fine... saved our bacon.

[GILow]

Originally Posted by Brian.D

23' is one of the optimal lengths for a vertical. You will attach it any way you can to the boat. Run the GTO15 from the tuner to the base of the antenna. The boat's counterpoise should be intact but if not, you can drop a wire about 6" into the water from the tuner's ground lug.

If built correctly, it should telescope into itself to save stowage space.

Check out this link https://g8jnj.webs.com/usingautotuners.htm

Brian, thank you, this is the sort of advice I was looking for.

I think I can construct a 23 foot whip from three 8 foot sections of tube, or maybe 4 six foot sections, each a size smaller than the last. Perhaps I could leave the lower section in place... Or maybe just pre-fab some kind of bracket I can easily drop the assembled antenna into.... Plenty of options there for a guy with a welder.

Just need to check where I would store the sections below decks... maybe transverse between the deck beams, along with the fishing rods.

To answer your question, I would assume the counterpoise would be unaffected, I have a dynaplate about four feet from the stern, directly below the ATU which is in the aft cabin. If those two are compromised then I'm probably at the "push the big red button and jump in the life raft" stage, not the "hey, I better let everyone know I'll be late to the party" stage.

[GILow]

Originally Posted by El Pinguino

Buy a squid pole.... https://www.ebay.com.au/itm/HAM-Radi...EAAOSwZVlXqq3h take rubber bobble off top....run copper wire from tuner through deck gland to bottom of squidpole and then up its insides ..... duct tape end of wire at top of squid pole...... secure squid pole to taffrail with duct tape..... also tape the joints in the squidpole so it doesn't do whatever the opposite to telescope is.....
As purchased the squidpoles are about one metre long... extended you can buy from 6 to 10 metres in length.

Your tuner should have no problem tuning it.

Mine lasted some years before having a fatigue failure in way of the top of the taffrail. They can flex a fair bit so make sure it can't mate with the blades of your windgen.
My Tasmanian Moonraker did the same thing a few years later.... I just cropped 2 feet off the base of it... still works good.
First pic..... moonraker on boat....some time prior to this photo being taken... on a long sea voyage... the top half unwound and fell off one dark and stormy night.... you can see where they are joined.... tuner still tuned the stump just fine.
Second piccy.... squid pole on top of 2 inch pvc pipe with SEA tuner at base... down on the campo.

When my mast fell down I didn't have a squid pole .... built an A-frame out of 2 spin poles.... ran copper wire from aft over the top of A-frame to pulpit ...worked just fine... saved our bacon.

Thank you EP... this suggestion of yours is ringing a bell. Have you told me this before and I have somehow lost your advice? If so, my humble apologies.

So, which way would you go if you were starting from scratch? Squid pole or aluminium sections?

[GILow]

Originally Posted by RaymondR

Get a piece of that blue lay flat hose and plug the ends with the valve stem out of a push bike rube in one end and run a wire up the inside of it. Inflate until sufficiently tumescent and stand on it's end, connect to transmitter and go for it.

That is so clever I feel I should have it on board regardless.

It reminds me of those annoying inflatable banner characters they use for retailers having big sales.

[El Pinguino]

Originally Posted by GILow

Thank you EP... this suggestion of yours is ringing a bell. Have you told me this before and I have somehow lost your advice? If so, my humble apologies.

So, which way would you go if you were starting from scratch? Squid pole or aluminium sections?

If only for emergencies..... squidpole.. ($30 ) , Wire ( $20?), Duct tape ($5?)

If permanent just buy an alloy tube. That Moonraker is simply a tapered alloy tube with a joiner in the middle ... all shrinkwrapped in plastic...plus two plastic stand-offs and two nut and bolt combos....

If you've forgotten asking the question I have also forgotten giving the answer..

[GILow]

Originally Posted by El Pinguino

If only for emergencies..... squidpole.. ($30 ) , Wire ( $20?), Duct tape ($5?)

If permanent just buy an alloy tube. That Moonraker is simply a tapered alloy tube with a joiner in the middle ... all shrinkwrapped in plastic...plus two plastic stand-offs and two nut and bolt combos....

If you've forgotten asking the question I have also forgotten giving the answer..

Thanks mate...

Geez, they want nearly $1K for a moonraker. What the heck is THAT about?

[GILow]

Originally Posted by El Pinguino

If only for emergencies..... squidpole.. ($30 ) , Wire ( $20?), Duct tape ($5?)

If permanent just buy an alloy tube.

Maybe both?

Seriously, I've just been looking at the squid pole and they just seem so bloody clever. So simple to stow below with a roll of wire ready threaded, all in a bag.

I see they do a longer version, any advantage? Prices are very comparable.

[El Pinguino]

Advantages would being able to tune lower frequencies and a serious 'cool' factor...

Disadvantage would be that they bend quite a bit....

Buy two... its not pretty when the wind gen eats one... don't ask....

[Jim Cate]

And Matt, after sending out your emergency message via squid pole antenna, you can do some emergency fishing/squid jigging with it while awaiting an answer!

And FYI, when we were dismasted I draped a random length of hookup wire from the backstay chainplate (where I fed my no-insulator light it all up rig) to what was left of the bow pulpit (the highest remaining bit on the boat) and checked into the Comedy net as usual, mentioning casually what had happened. Bad idea! They all wanted to come rescue us, and we didn't need or want rescuing. But anyway, it worked pretty well and cost nothing... my kinda deal!

Jim

[GILow]

Originally Posted by El Pinguino

Advantages would being able to tune lower frequencies and a serious 'cool' factor...

Disadvantage would be that they bend quite a bit....

Buy two... its not pretty when the wind gen eats one... don't ask....

I am not sure my boat will ever look "cool". No matter how many antennas.

But yeah, the Aerogen 6 could chew through quite a bit before it surrendered. If my HF theory is ok, the lower frequencies are the ones I will want in a coastal emergency, and the higher frequencies if I am way off shore?

Maybe one of each squid pole. Seriously, I have been staring at AU$900 antennas for so long now that the thought of spending AU$80 for a pair plus a few $ for the wire is very appealing.