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Author Topic: What Screwdriver Antenna To Buy And Why  (Read 18090 times)
GOLDTR8
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Posts: 54




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« on: August 09, 2010, 05:05:14 PM »

Fellow mobile operators,

I want to upgrade from my hamsticks to a screwdriver antenna.  I have been looking at reviews and I really can not decide what is best or best bang for the buck.

I have looked at Tarheels, Hy-Q, Seirra, and Alpine.  I know there are more out there but this is where I am at.

From my research I believe that the HY-Q has the best coil Q and efficiency.  However for the price I am not sure there is enough difference in the overall efficiency to justify the high price.  This is why I am leaning towards an Alpine.

My rig is an IC-7000 mounted in a 2008 jeep wrangler.   

So those with experience please give me your advice, and also how are you tuning your screwdriver.

Thanks in advance for your help.

Don
KD8NNU
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WX7G
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« Reply #1 on: August 09, 2010, 06:10:04 PM »

What bands will you operate on?
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KL2GN
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« Reply #2 on: August 09, 2010, 06:11:24 PM »

Hi Don-

Congrats on working to upgrade your mobile operation!
As I am sure you have found reading, everyone has an opinion on the various styles of antennas for mobile operation.  I have found over the years that antenna selection for mobile use is really a combination of a lot of factors - vehicle size and mounting capability, height restrictions, frequencies you prefer to operate, and the amount of time and money you are willing to put into the system.

Personally, I have a 3/4 ton long bed crew cab diesel pickup.  I run 2 HF antennas - a HI Q 4-80 on the front bed corner behind the driver and a whip or texas bugcatcher on the rear passenger side corner in addition to various VHF and scanner antennas on the roof of the cab.

I run the 4-80 with an MFJ inductance matching box to a IC-7000 with a DC controller in the cab.  I use a shunt coil on the bug catcher and can A/B between the antennas from the cab.
I used to use a better RF controller with the Hi-Q but found myself spending most of my time on only a few bands and I like the DC controller.  I chose the HI-Q because living in AK and having winter weather for 6 months or more of the year I liked the enclosed coil and not having an antenna that changed length (unless I change whip length).
If I had to do it again, I would either use the HI-Q or a scorpion.  Both great products.

And just to make things more interesting - the bug catcher is consistently the better antenna - in my situation and in my install from 40M on up....but it doesn't care for the weather up here very much and you do have to change tap points for bands...lol

Best of luck,
Tim, KL2GN

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GOLDTR8
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« Reply #3 on: August 09, 2010, 06:21:13 PM »

What bands will you operate on?

Only 75M to 15M as that is what I have for Hamsticks.  I would like to drop down to 160M but its not required.

Thanks
Don
KD8NNU
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WX7G
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« Reply #4 on: August 09, 2010, 07:21:06 PM »

Of the three screwdriver antenna companies mentioned only Hi-Q sells a 160 meter antenna.

On 15 meters the Hamstick should be as good as a screwdriver. 80 meters is where you will notice a difference of a few dB.
« Last Edit: August 09, 2010, 07:22:51 PM by DAVE CUTHBERT » Logged
K0BG
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« Reply #5 on: August 10, 2010, 06:52:54 AM »

Scorpion also makes a 160 antenna, but there is something else to consider.

If you compare any 160 meter model, with its stablemate 80 meter version, the difference in field strength on the upper bands is about 3 to 5 dB. While not significant, there are times when it is the difference between making a contact, and not.

The same can be said for the difference between a Hamstick, and a decent screwdriver. On the lower bands, the difference can be as much as 15 dB, perhaps a little more depending on how it is mounted. On the upper bands, the difference is somewhat less.

I can't speak for anybody else, but I put a lot of effort into my mobile as that is where 90% of my air time takes place. Call it a best foot forward approach. Your ideal may be less stringent.
« Last Edit: August 10, 2010, 12:20:20 PM by Alan Applegate » Logged

WX7G
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« Reply #6 on: August 10, 2010, 09:47:29 AM »

Alan, are you saying that on the upper bands the 160 meter version will be down 3-5 dB from the 80 meter version?

And are you saying that on the low bands the 160 meter can be as much as 15 dB down from the 80 meter version?
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AF6WI
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« Reply #7 on: August 10, 2010, 10:38:42 AM »

I've got a Tarheel model 100 on my van. I tuned it using MFJ's antenna analyzer and use the motor and programmable controller that came with it.

I picked Tarheel over the other makers after reading the reviews here and noting which ones were reported as giving better support.

I've read all the hoopla about Q and such, and my bet is that you can't tell one from another in a blind test. My goal was to be able to get help, and Tarheel has done well by me. I believe they sold the business after I bought it, so keep that in mind if you're looking for service. If it's been sold, service will have changed, whether for good or ill.
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K0BG
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« Reply #8 on: August 10, 2010, 12:19:03 PM »

Dave, I should have put a return in there. I was speaking about the difference between a Hamstick, and a decent screwdriver.
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KE4DRN
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« Reply #9 on: August 10, 2010, 03:01:27 PM »

hi,

the owner of Tarheel antenna, Robert did sell the company to
WB0W, Gaylen  but nothing has changed, same great antenna,
I have two of them.

Robert takes care of the support for the Tarheel antenna.

http://www.tarheelantennas.com/why_a_tarheel

http://www.wb0w.com/

73 james
« Last Edit: August 10, 2010, 03:03:19 PM by James » Logged
K0BG
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« Reply #10 on: August 10, 2010, 03:32:07 PM »

Phil, it depends on your definition of a blind test. I don't take all that much stock in antenna shootouts, for a variety of reasons. Regardless, there are consistent winners, and they seemingly are grouped into three bands. The consistent winners among Tarheels are the 200A, and 400A. Look at the 2010 data.

http://www.3905ccn.com/newsite/files/pdf/shootout-2010.pdf

If you look over The consistent winners are Scorpion, Predator, and Tarheel 200A, and in that order.

One of the more interesting aspects of the shootouts is who wins on what frequency!? Some of the absolute winners on 80 meters, drop way down on 40, and disappear on 20 and above. Those typically are the ones with rather larger metallic end caps, like the HiQ, and Hustler large coils.

Another interesting outcome, are the properly installed hamsticks, with properly implemented cap hats. They often beat much higher Q antennas without cap hats. Again, it does depend on the frequency we're discussing, and how/what that cap hat is. It also shows how important cap hats cab be, even when the coil Q is less than ideal.

It is also interesting to note, that in some of the yearly tests the difference between last, and first place is only a few dB, while other years it is as much as 15 dB. I suspect I know the answer to this conundrum, but I don't know enough about the individual tests to be sure.

If there are consistent winners, it's decent quality screwdrivers (coil Qs over 200 or so, i.e.: Scorpion, Predator, Tarheel 200a), with cap hats mounted at the very end of the whip.

The bottom line is, how gung ho are you?
« Last Edit: August 10, 2010, 03:36:31 PM by Alan Applegate » Logged

GOLDTR8
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Posts: 54




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« Reply #11 on: August 10, 2010, 05:24:57 PM »

I can find where you buy a Scorpion, but not a Predator.  Is Predator no longer in business. 

Alan you recommend an antenna that goes to 160m as this will have higher overall receive and transmit on higher frequencies.
What I do not understand if you go to Scorpion web site the SA-680 Q is 410 and the SA6-160 Q is 380 so doesen't mean the higher Q coil would be better.

I am still learning this stuff so if someone can explain I would appreciate it.  As we all know there are low price versions and high price versions out there and if you choose wrong its even more expensive, which is why I am asking for info.

The free ham-sticks have run their course.
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WX7G
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« Reply #12 on: August 11, 2010, 08:46:09 AM »

The 3905 antenna shoot report out for 2010 is pretty useless. What band was tested?
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N5MOA
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« Reply #13 on: August 11, 2010, 09:59:41 AM »


If you look over The consistent winners are Scorpion, Predator, and Tarheel 200A, and in that order.


I don't take much stock in the antenna shoot outs either. On one hand, the 2010 shootout results talk about how improper low mounting on a trailer hitch is, but third place was a trailer hitch mount. Maybe it was a high trailer hitch mount?  A lot of trailer hitch mounts scored well.

The results are all over the place. Looking back at the winners from 2002-2010

2010 Scorpion
2009 Tarheel 100 AD
2008  HI-Q
2007 Ameritron
2006 Ameritron SDA 100
2005 Tarheel
2004 High Sierra
2003 Hustler
2002 Perdator

So it looks like the consistent winners are Tarheel and Ameritron in a tie, then everyone else.

What frequency do they use for the shoot out?

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K0BG
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« Reply #14 on: August 11, 2010, 11:24:27 AM »

They do it every year, but at different locations in the US.

There are a bunch of issues with respect to shootouts, that don't commonly get discussed. I outlined those (most of them anyway), in an article on my web site.

If the only thing you looked at were the difference in signal strength between two different models being say 3 dB one year, and 10 dB the next, should cause one to ponder the validity. No doubt the biggest errors are the fact that the field strength measurements are taken in the near field (<4 wave lengths), and at only one TOA. As a result, they tend to be more of brag fest, which is fine as long as you realize that's what they are.

This said, it is interesting which antenna consistently win; it's always ones with properly mounted cap hats.

Dave, this year, and last, were both done on 40 meters. Previously, 80 was used. If the tests were done on 20 meters, some of the clear winners of the past would be dead last. That's covered in the article too.
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