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Author Topic: Max Power into a 20 Meter Hamstick  (Read 1905 times)
IRABREN
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Posts: 273




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« on: March 05, 2008, 07:52:39 PM »

I am setting up a modest station ( and I mean modest )
Wish to use a 20 Meter Hamstick mag mounted on top of the car - outside the house
How much power is safely transmitted to a 20m hamstick?
Can they take up to 400 watts ?
Thanks and 73
Ira, KE5STP
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W5FYI
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« Reply #1 on: March 05, 2008, 08:02:34 PM »

The web site, www.hamstick.com, rates them at 600 watts peak envelope power. I would guess that's for a new antenna; one with dirt and grime around the helix portion, especially if it's wet, may overheat the antenna with somewhat less power.

FYI, Stew
 
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N3OX
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« Reply #2 on: March 05, 2008, 08:36:50 PM »

Ira,

Running an amplifier into a hamstick as a home station doesn't make sense.

You will make some contacts, but it would be much better to have your $1300 back to put into antennas.  I imagine you're in some sort of situation where you need stealth but there are a hundred better ways to do this.

A hamstick on your car will turn a huge amount of your expensive wattage to heat.  

It may seem useful to have a 600W amplifier.  You might think it will give you a strong signal, but what's really going to happen is that a guy like me who's never run more than 100W and is currently running a hundred dollar homebrew beam at 30 feet is going to kick your butt up and down 20m, signal wise.  I'm not kidding, I'm being very literal.  Your 600W is going to sound like me running something like 20W.

There's nothing wrong with having an amplifier, but put up a real antenna.  Seriously.  Put up a real antenna.  Figure out how to do it even if it seems impossible.

The antenna is the MOST IMPORTANT PART of your station if what you want to do is hear well and have a strong signal. It may sound like a tired old platitude or something but seriously, until I started operating 160m I could count on two hands the times I needed an amplifier.  There have been a few occasions when I heard a station on a tough propagation path, Southeast Asia or some such where I tried to call back and they just CQ'ed in my face.  All those thousands and thousands of other times I was trying to contact some far off DX, I did not need an amplifier because I run pretty good antennas.  I don't run HUGE antennas on a big tower, I just run pretty good antennas.

Even on 160m I probably have a success rate of 70% + with not very many stations CQing in my face.

I am finally, after 13 years as a ham, building an amplifier for 160m because I need to make up for a compromise antenna, and that is a valid thing to do, but to hear that you spent big bucks on the amplifier *first* and then intend install an antenna as terrible as a hamstick makes me a little depressed.

It's just not a very important part of the station for a new ham... it's a great upgrade once you've put some effort and money into antennas.

73,
Dan

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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
IRABREN
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Posts: 273




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« Reply #3 on: March 05, 2008, 08:47:01 PM »

Thanks Very Much and I certainly understand your point. I do have on order " a real antenna" - Force 12 Sigma 40XKR
a vertical dipole 15 FT off ground  - for the backyard. It takes 12 weeks to make it ! - The 20 meter hamsticks - do however have pretty good reviews - it seems - people either love or hate them. Well what can you get for $30 - The Force 12 costs over $500 !!
73'
Ira, KE5STP
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N3OX
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« Reply #4 on: March 05, 2008, 09:05:35 PM »

"Force 12 Sigma 40XKR "

OK good... those seem to work reasonably well.

"It takes 12 weeks to make it ! "

True true...

"Well what can you get for $30"

17 feet of metallic electrical conduit and 50 odd feet of wire to make a 20m ground plane with three radials... it'll blow the hamstick out of the water and will handle 600W keydown with no problem (dipoles and ground plane verticals have huge power limits, nothing fancy to overheat).  Probably even have some money left over.

It probably would work pretty similarly to the Force 12 antenna.... and with 3 months wait, it's worth having a real antenna.

I see they didn't leave you with much in the way of antenna supports in your development there, eh?  If you have even one tree, you can hang a sloping dipole that will work great.

The Force 12 is a cool antenna but very simple in concept and execution and if you just want to get started on 20m, an inexpensive dipole or groundplane will work just as well.  A hamstick will NOT.


73,
Dan

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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
K6AER
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Posts: 3497




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« Reply #5 on: March 05, 2008, 09:09:20 PM »

With 450 watts SSB into a 20 meter hamstick my coil eventually burned. After the coil was increased in diameter to 2 inches and rewound with number 14 gage wire I have had no more hamstick burning problems.

W6TR will rewound you ham stick for higher power handling capabilities.
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K6AER
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« Reply #6 on: March 05, 2008, 09:18:14 PM »

Something I forgot to add that a hamstick will exhibit much lower efficiency than a plane old dipole. If you can put up any resonate vertical or dipole you will have a much more efficient antenna.  

Now as for running amplifiers it ok if you have put up the maximum antenna allowed due to a verity of reasons.  With an inefficient antenna being the best you can manage, power will help you be heard on the other end. If you are having a problem hearing my station due to local noise, I will gladly turn on may amplifier to make the QSO more enjoyable.
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IRABREN
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« Reply #7 on: March 05, 2008, 09:18:19 PM »

Yes I am sure you are absolutely correct and I see your point - You have a more cost efficient method  - BUT.....
I am old and just starting - with no background in electronics at all! I live in a new homes development - no trees; CCR restrictions - 4 small dogs - in a pint sized backyard.
I would not have the slightest idea - what to do with electrical conduit and wire etc etc. I am not much of a technician - more an operator. I was researching an Antenna - that would be quick deploy & take-down; no radials and vertical. So - this force 12 seems to fit the bill. Now if I was 50 years younger and just starting - I would want to learn how to make an antenna - but I am not very handy.
Thank You Kindly for you time, patience and information and Good Luck with your projects !
Ira, KE5STP
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N3OX
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« Reply #8 on: March 05, 2008, 09:24:54 PM »

K6AER writes:

"If you are having a problem hearing my station due to local noise, I will gladly turn on may amplifier to make the QSO more enjoyable."

A problem hearing your station?  Ha!

I was tuning across 20m late last night and heard you signing off on an otherwise nearly dead band, you were 59+15dB ;-)

KE5STP says:

"I was 50 years younger and just starting - I would want to learn how to make an antenna - but I am not very handy."

Understandable... have fun!  

Dan



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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
WA3SKN
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Posts: 5453




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« Reply #9 on: March 06, 2008, 03:44:16 AM »

I believe that Hamstick rates their antenna at 400 watts max.  However, I would not use such power.
Remember that the real limitation is either "breakdown voltage" or "current limited", and that these will be affected by the impedance where the antenna is installed... not a "lab controlled environment" the company uses.
"Common sense and logic" should be applied here!
73s.

-Mike.
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NI0C
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Posts: 2391




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« Reply #10 on: March 06, 2008, 04:24:42 AM »

N3OX wrote:
"The Force 12 is a cool antenna but very simple in concept and execution and if you just want to get started on 20m, an inexpensive dipole or groundplane will work just as well. A hamstick will NOT."

I agree about the hamstick; however the Force 12 Sigma 40XKR is an excellent antenna, and should perform better than a low horizontal dipole or groundplane.  

I've purchased several Force 12 vertical dipoles including the Sigma 5, GT-5, 40, and 40XK, and am very pleased.  When following up on your delivery from Force 12 (and you probably will have to follow up), do it by telephone, be very nice and polite to the office staff, and ask for an estimated delivery date, and be flexible.  You will get eventually get your antenna if you are patient enough to wait for it.

73 & GL,
Chuck  NI0C
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K0BG
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« Reply #11 on: March 06, 2008, 06:52:14 AM »

Just for fun a couple of years ago, I stuck a 20 meter Hamstick on my ballmount in place of my HiQ. With 500 watts carrier, it lasted all of 5 seconds! When it failed, it actually sounded like a firecracker, and was smoking! Does this answer your question?

Alan, KØBG
www.k0bg.com
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IRABREN
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Posts: 273




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« Reply #12 on: March 07, 2008, 10:14:26 AM »

Someone told me that the "Hamsticks" are not resonant and I believe he is correct. I tested my 20m stick with an MFJ-259b and I could get the SWR down to 1.2 by changing length of the whip - BUT - the impedance did not show 50 ohms - it was way off. The radio (FT-950) - internal tuner - still shows a high SWR before it starts to tune.
Ira, KE5STP
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AA4PB
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« Reply #13 on: March 07, 2008, 04:25:30 PM »

Resonance and impedance are two different things. Resonance means that there is no inductive or capacitive reactance but it doesn't mean the resistive component is 50 ohms or that the SWR is 1:1. Ideally you adjust the whip length for resonance and then provide some sort of matching network at the base to convert the impedance at resonance to 50 ohms. I find that decent Hamstick installations at resonance have a resistive impedance of around 25 ohms. A 2:1 UNUN at the base easily converts that to 50 ohms. The nice thing about an UNUN is that it is broad band (80M thru 10M) whereas most other matching methods require a change in the matching device for different bands.

Bottom line, a 20M Hamstick can be adjusted for resonance on 20M but the SWR will be 2:1 without some sort of impedance matching.
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IRABREN
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Posts: 273




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« Reply #14 on: March 07, 2008, 06:54:17 PM »

Thanks - excellent - outstanding answer - BUT - (being the beginner that I am ) - How would I connect a 2:1 Balun at the base of the Hamstick antenna? I looked at DX Enginering Baluns - they have an so239 connector at 1 end for coax - but what is connected at the other end? The Hamstick is mag mounted on top of the car with RG58 cable coming from the mount.
PS - I do plan to use a Palstar AT1KP Tuner - but perhaps adding a balun would be useful ( Huh)
Many Thanks for your patience with my ignorance!
Ira, KE5STP
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