40m mobile with a 20m hamstick type antenna

[mr_fx]

ok I know this sounds weird... but this is what I am thinking

I have a WORKMAN 20m hamstick, this unit unscrews in the center allowing the whip and adjustment section to be removed...

I am considering turning a coil to mount in the center, so it might load up on 40m... or removing the 4ft whip and replacing it with a 4 or 5 foot tall fiberglass whip which I would return for 40m (less the existing 4ft 20m section)

which idea sounds better?

also I have to stuff laying around to do this, it will not be a big deal to pull this off... bu a workman 40m hamstick type antenna is only $20-25 locally

 

[Captain Kilowatt]

Get a 40m stick. Unless you are real lucky retuning a 20m stick will be a HUGE headache. Actually you would be far better off with something better than a hamstick on 40m which means almost anything different. Been there. Done that. Don't bother anymore.

 

[mr_fx]

well so far I have had a little fun, took the top section (4ft) off and made a short 2" top section that screws in for 12m, and a 8" section for 15m, everything seems to work so far...

made the swapable top sections out of some old radials from a A99 antenna

I also found that the 20m ham stick minus the top section is tuned for around 26.5mhz... weird if you ask me

 

[Captain Kilowatt]

Using those short stingers with the 40m coil may tune but wll be horribly inefficient. The 40m hamstick is already inefficient. If you want to go the hamstick route get several for different bands. I used one for 20m and another for 75m before turning to either my 102 whip and auto tuner or my homemade 15m mobile antenna that I used on 20m and up with the auto tuner. I preferred the latter. It was great on 15m without a tuner and real good on 20m with a tuner. It is about ten feet long overall with the bottom half helically wound with coax braid to reduce losses.

 

[mr_fx]

Kilowatt you misunderstood what I was doing here... The plan was to make a quick change coil for 40m... It would sit between the bottom section and the top section, making the antenna approx. 10ft tall

So far I have come out a head. $5 at a ham fest for the Workman 20m ham stick type antenna, $1.50 for some 2 part epoxy, $3 for a roll of heat shrink tubing, a little time and some solder, just chopped down a old CB antenna and rewound it until it worked

Now the antenna works on 12m, 15m, 20m and 40m

 

[mr_fx]

well so far everything works. no contacts on 12m yet, but plenty on 40m and 15m

I am sure I could do better, but the price is right, and it was a fun project

Here is a pic with the 40m resonator added, it screws in and out at will, it is tuned so that the 20m whip does not need the height changed

15 and 12 also have there own 'stubs' that replace the 20m section...

 

[davegrantsr]

well so far everything works. no contacts on 12m yet, but plenty on 40m and 15m

I am sure I could do better, but the price is right, and it was a fun project

Here is a pic with the 40m resonator added, it screws in and out at will, it is tuned so that the 20m whip does not need the height changed

15 and 12 also have there own 'stubs' that replace the 20m section...

that'd last the 45 seconds it takes me to get to the 10' 6" railroad bridge.....

 

[mr_fx]

that'd last the 45 seconds it takes me to get to the 10' 6" railroad bridge.....

so unscrew the center and top section when and if you get there...

 

[Captain Kilowatt]

Kilowatt you misunderstood what I was doing here... The plan was to make a quick change coil for 40m... It would sit between the bottom section and the top section, making the antenna approx. 10ft tall

So far I have come out a head. $5 at a ham fest for the Workman 20m ham stick type antenna, $1.50 for some 2 part epoxy, $3 for a roll of heat shrink tubing, a little time and some solder, just chopped down a old CB antenna and rewound it until it worked

Now the antenna works on 12m, 15m, 20m and 40m

Yeah I thought you were using a 40m stick with short stingers. In any event even the 20m stick with short stingers will be less efficient on the higher bands than a stick for that band due to the shorter overall length and using more coil turns than is efficient for that band. It will tune for sure but low SWR and efficiency are not related.

Just wondering how tall that 20m + 40m whip is from the ground to the tip. Most trucks have a height limit of 13'6" for bridge clearances etc. My home made 15m antenna is about 10 feet overall and I had it mounted on the rear hatch door of my Ford escape that I had at the time. It was about 3 feet + off the ground which made the tip right at 13'4". BTW you would do better with it on the drivers side. Less tree branches to whack. I used to have a VHF/UHF antenna on the drivers side but moved it to the passengers side to accommodate the HF antenna after hitting everything there was to hit here in town. We have a lot of trees here in town.

 

[mr_fx]

about 150" at tip

 

[Captain Kilowatt]

OK so you are about a foot shorter than what I had. I would be careful with it at highway speeds however. It is fairly thick and offers a lot of wind drag. You want to make sure the mount is good and solid and make sure you don't snap it off at the base.

 

[Moleculo]

Hehe. For the price you paid for everything, you got your fun out of it. Sometimes experimenting with something just to see if you can do it is worth the fun even though we all know that it's not the most efficient or best setup. And the fact that you've made plenty of contacts validates the fun part.

Nice pics, BTW...really helps show what you did with this!

 

[mr_fx]

the mounts are homemade, I removed the tail lights and there is a nice section of sheet metal that is double thick and I bolted that in added a back plate and also a self tapping screw...

as for the highway thing, it whips around like piss in the wind... so I added a 12 lbs test fishing line guy wire

I figure this setup can't be any worse than a bottom loaded setup like a screw driver... hell might even be a little better, at least most of the loading on this setup is higher up and above he roof line...

Best part is it unscrews and you just remove the coil, replace it with only the top section and you have 20m

OR

replace the 20m stinger with a 6" or so stinger, now you got 15m, it would be better if the 15m setup was taller true, but who care, it works

or

replace the 20m stinger with a stub (basically a whip mount minus the whip) now you got 12m

 

[Moleculo]

I figure this setup can't be any worse than a bottom loaded setup like a screw driver

Actually from a performance perspective, it's significantly worse, but that doesn't really matter because you're having fun. The performance issue is due to the long, super skinny loading coils. Good screwdrivers have wider, larger coils with a lot less turns, making them waaaaaaaay more efficient.

 

[mr_fx]

Actually from a performance perspective, it's significantly worse, but that doesn't really matter because you're having fun. The performance issue is due to the long, super skinny loading coils. Good screwdrivers have wider, larger coils with a lot less turns, making them waaaaaaaay more efficient.

I see.

well not really a big deal, next on the list is a homemade setup similar to the hustler, might even make is hustler compatible..., just not sure what to use for the forms for the coils.