Dumb ???? #4 (robust antenna)

[wyojeepeer]

If you've been watching the news, you've seen that here in Wyoming we've had winds up to 120 mph, this year.
So... I've been thinking (I know, dangerous) what happens if I put additional tubing over the factory, to make it stiffer?
I have a couple antennas to use for parts (a Chicom 1/2 wave, and a Venom 5/8 that bent in a month).
I realize that the fit has to be reasonablily tight.
Would it affect rx/tx?

Any other recommendations/ opinions?

Thanks, John

 

[dave457]

I don't believe any antenna would survive that type of wind regardless of how much you beef it up

 

[wyojeepeer]

What???? no Viagra comments???

I'm asking not so much for me as for people new to the hobby.

The antenna i'm working on is a New Tornado.
I know that I'll have to connect the inner and outer tubes for continuity.
I also know that they only need to be about one half the length of the tube they cover.
Anything else?

Thanks, John

 

[wyojeepeer]

I don't believe any antenna would survive that type of wind regardless of how much you beef it up

Winds at the house only reached 70+.

 

[wyojeepeer]

Winds at the house only reached 70+.

Well, well, well.

The Chicom antenna has the same size tubing.

The 5/8ths Venom, on the other hand, has slightly SMALLER tubing that fits inside the Tornado tubing. A reasonably tight slip fit.

Now the only problem is that last joint (of six) that don't want to go together. I'll fight with it tomorrow some more.

BTW, had to use Channelocks on the screws 'cause of how thick the metal is now.
It seems to be a lot stiffer.

Thanks, John

 

[Eldorado828]

If you've been watching the news, you've seen that here in Wyoming we've had winds up to 120 mph, this year.
So... I've been thinking (I know, dangerous) what happens if I put additional tubing over the factory, to make it stiffer?
I have a couple antennas to use for parts (a Chicom 1/2 wave, and a Venom 5/8 that bent in a month).
I realize that the fit has to be reasonablily tight.
Would it affect rx/tx?

Any other recommendations/ opinions?

Thanks, John

Not 120 mph here but we're no strangers to the wind scenario here in the Texas panhandle. My sigma venom lasted 2 wind seasons ( I was surprised) and that was it, last spring it got turned into a banana shape after 2 days of 65 to 70 mph gusts.. I've been through a dozen antennas in the last 15 years and all didn't survive the spring winds. I'm currently on a sirio 2016 and so far it's survived 65 to 70 this season but I also scope the mast down to about 25 feet at the bottom of the antenna to help. During storm season I lay the whole mast over to prevent damage all together.

My point is that we just have to learn to live with it and take measures to help mitigate damage.

I've tried the antenna modifications before and it's just not worth it. As mentioned by someone else, nothing will survive those kinds of winds without some sort of damage. You'd be better off finding other ways to mitigate damage.

Just my opinion for whatever it's worth.

 

[wyojeepeer]

Yesterday had winds of about 45 mph.
After finishing the last joint, I stood it it up on the deck and compared it to the 8' fiberglass radioshack whip I'm currently using...... It was bending much less. About half as much. I think I might have to guy my push-up mast.

Cheers to all.

 

[wyojeepeer]

More info.

Lying on it's side, over a distance of 16' from the base, it bends about 4".
I didn't say, but where the joints are, all the tubing overlaps, which should make them very strong.
I also put a liter soda bottle over the coil to help protect it.

Cheers to all.

 

[wyojeepeer]

I finally got a chance to work it some more.
I found the the venom's main tube is exactly the same size as the tornado.That's in side(tornado) to outside(venom). So I split the venom's main tube lengthwise. And installed 27" with a rubber hammer. A very tight fit.
I had to be careful not to put to much of the venom's tube inside so I didn't shear the connection for the loading coil.
This thing now weights a ton.
The next step is disassemble it one more time and put whats left of the venom's main tube (a little over a foot) on outside of the main tube of the tornado, right above the coil, to stiffen it a little bit more.

Gonna be interesting to see if this old man is able to pick it up and mount it.

C'ya.

 

[gamegetter]

good lord, i think 120 mph is like a cat 3 hurricane. there will be serious structural loading and of course possibility of flying debris. at this point, survival of the antenna depends as much on the mount and tower as the antenna itself being engineered well enough to handle the event. i think antenna thick walled tubing with internal reinforcement is best as well.

if you are using the sirio tornado 27 it should be rated up to 80 mph i believe, but mounting matters a lot because the radials add wind load to the situation. if windy and icy, stress is also increased. Proper guying is important because sometimes even guy wires can snap or come loose, so quality does matter at the higher wind speeds.

reiterate: heavy duty tower or mast, guy wires, and well constructed antenna and that everything is installed and tightened well with frequent checks on condition of the items.

a low profile antenna is a plus but our goals on hf challenges us a bit.

 

[snippits75]

120 mph wind...wow. That's as strong as a F2 tornado.

Had a F1 tornado, at wind speed 105 mph, come high above my home, and it bent a Sirio four element like cooked spaghetti noodles. 1.25 inch inside diameter galvanized pipe at 21 feet stayed straight. The pipe is slightly over 1 5/8 inch diameter on the outside.

If the tornado had been on the ground, it would have been a bigger mess than what it was.

 

[AudioShockwav]

I know someone who mounted a full 5/8 ground plane in the back of a Ford pickup truck and blasted down the desert highway at 100 mph just to prove that the antenna would handle it but, wow ,120 mph gusts is just insane.
I lost a PDL II in a thunderstorm one spring with gusts reported to 85 mph and it really shredded it.
Best way I can think of to ensure that your antenna survives that is to crank it down below roof level until the storm passes....

73
Jeff

 

[bob85]

ALL sirio antennas are useless in high wind,
sirio use .049" wall 6063-t832 swaged tube with thicker wall lower sections on some of their antennas,
The sheet metal screw & plastic sleeve joins are useless,

venom use recycled turkey foil beer cans & chewing gum Alloy = amongst the weakest antennas available,

A1 antennas i10k is one of the strongest cb antennas in wind,
It uses 6063-t8 .058" wall tube which is not the strongest but the way its constructed with a good fit between sections & the step down fast taper helps a lot with wind survival,

( I10k is the only antenna in this area that has survived 20 years on a hill without bending / snapping or needing taking down to fix /retune ) no other antenna has come close to that durability,

Avanti used 6061-t6 x .058 as does mr coily,
my choice of tube because it fits together well its available in plenty of sizes to make a fast taper & its stronger than 6063-t8

Vortex antennas use AA6082-t6 tube which is the strongest tube I have seen used in cb antennas,
conversely the way they are constructed with too few & longer sections makes them not very strong in wind and crazy heavy & top heavy,
the fit of the tubes is sloppy & not enough sizes are readily available to build a fast taper strong antenna,


If you get high winds you need a flexible mast that sways in wind, never a rigid mast,
most high quality cb antennas will withstand more than 70mph if they are on a flexible mast

The only option That may survive 120mph winds is to build your own crazy spec antenna.

 

[wyojeepeer]

Well,
Couldn't stretch that last piece over the new tornado main tube so I'll just do without it.
The reason for the stoutness is where I live the wind is rarely below 30 mph, usually higher. 50mph gusts are rather normal. The venom only lasted a month. Combined with the new tornado, I "should" be good.
I will be reinforcing my pushup mast, putting the base of the antenna at 18 feet.

C'ya.

 

[wyojeepeer]

Hey,
Wind today is 20, gusts to 30.
I got it stood up at around 9'.
SWR at 1.1:1 on 38. Very slightly higher on channel1, 1.15:1.
I set the top (tuning) at about 980mm.
Now I need to put the radials on.
And run it past my VNA to see what it's really doing.
It still has some flexibility in it, so here's hoping.
Also, choked at the feed point.
50' RG8x.

Hope this helps someone.

C'ya.