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Author Topic: mini screwdriver or 8.5' whip  (Read 4246 times)
N5MOA
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« Reply #15 on: July 11, 2011, 01:54:38 PM »


Every mobile operator has to establish his or hers level of performance. If you're willing to squeak by, fine. I'm not!

I'll agree with this statement. Different strokes.  However, it appears to me to be at odds with your following statement:

The ability to work a DX station has nothing to do with the antenna in use. It has to do with band conditions. Nothing more, nothing less.



If it is ALL band conditions, what is the point in trying for the most efficient setup?

If it is all band conditions, wouldn't it be a lot easier, and just as good, to slap a hamstick on a mag mount on the roof, and be done?

You make it sound like all antennas are created equal. You've said yourself they aren't, which makes the "has nothing to do with the antenna in use" comment even more surprising, coming from you.

The antenna in use doesn't make much difference when signals are strong, at least on the higher bands.

When signals are weak is when the antenna, and that last db squeezed out of the setup, can make the difference between a qso or not.

Especially on 40m, 80m or 160m.



One thing is for sure, you can tell who uses DX contacts as a justification.



Yep. It's easy. And it's just as valid a justification as "can't really be measured, but must be".

 Get two vehicles, put your favorite antenna for today on one, something else on the other. Mount each as properly as possible. Park them 50 ft apart, get a couple of 50 ft jumpers, a coax switch and a radio.

Tune each for 40m. Now, tune around, see what you hear. Or what one can't. Find a weak station and establish a qso with whichever antenna will allow you to do that. Compare the two, if you can even have a qso with both.

Now, try it on 80m. 160m leaves a lot of antennas out, so go with whatever has the best results on 80m.

I don't have a degree in anything, or test equipment to check which antenna is more efficient than the another, so that's how I did it for myself. Real time, real world A/B checking.

I like to catch dx, not just chase it.  I chose to try and have the most efficient setup I could, because, in addition to having some propagation, the ability to work a dx station CAN depend on the antenna in use.


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M6GOM
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« Reply #16 on: July 11, 2011, 05:11:43 PM »

The ability to work a DX station has nothing to do with the antenna in use. It has to do with band conditions. Nothing more, nothing less.


Yeah because the fact I can do it every day of the week, every week of the year is quite irrelevant apparently as is the fact that I couldn't when I used the stock whip.

It has everything to do with BOTH. Neither is sufficient on its own. Sometimes when you post drivel like that, similar to your "every cars stock wiring without exception is insufficient to power a HF transceiver" rubbish I wonder if you've been on the moonshine when you posted it.
« Last Edit: July 11, 2011, 05:13:43 PM by M6GOM » Logged
N2RRA
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« Reply #17 on: July 12, 2011, 06:36:36 AM »

The ability to work a DX station has nothing to do with the antenna in use. It has to do with band conditions. Nothing more, nothing less.


Yeah because the fact I can do it every day of the week, every week of the year is quite irrelevant apparently as is the fact that I couldn't when I used the stock whip.

It has everything to do with BOTH. Neither is sufficient on its own. Sometimes when you post drivel like that, similar to your "every cars stock wiring without exception is insufficient to power a HF transceiver" rubbish I wonder if you've been on the moonshine when you posted it.

LMAO! quite true! LOL!
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K0BG
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« Reply #18 on: July 12, 2011, 12:52:09 PM »

You do it every week because of where you live. Most amateurs don't realize it is further from LA to NY, than it is from NY to London. Again, the ability to work DX means nothing. A low SWR, a high Q coil, extra whip length, big cap hat, and low ground losses, are no guarantee to working DX. The only thing that counts, is band conditions between the two points. Nothing more, nothing less.

Think about this too. If I draw a 1,000 mile radius on my QTH, I can work about 50 DX entities. An amateur living in Berlin, using the same 1,000 mile radius, could work well over 200. So what's the point?
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N5MOA
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« Reply #19 on: July 12, 2011, 01:33:50 PM »

A low SWR, a high Q coil, extra whip length, big cap hat, and low ground losses, are no guarantee to working DX.


I don't recall anyone posting in this thread that it was a guarantee. But it do help.



The only thing that counts, is band conditions between the two points. Nothing more, nothing less.



Again, if it is only band conditions, why go to the trouble of working toward the most efficient mobile setup?

Why even worry about antenna efficiency at all?

Anything will work as an antenna, it's all the band conditions, right?

If you believe that, you wasted a lot of time and effort on your own install.


There has to be propagation. That is a given. Taking as much advantage of said propagation as possible is where the install, and antenna, can make a difference between a qso or not.

You know as well as I do, some antennas are more efficient than others. Some radiate better than others. It is called ERP.

 Sometimes, 1000w gets through when 500w won't. Sometimes, 200w does it, 100w won't. Or 100w vs 50w. 50w vs 5w. The band conditions haven't changed, the ERP has.

It isn't "only" band conditions. The antenna can also make a difference.

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K0BG
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« Reply #20 on: July 13, 2011, 06:52:14 AM »

This horse is probably long since beat to death, but...

Using your analogy, why not just use dipoles, and forget about a beam? The reasoning should be obvious.
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N5MOA
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« Reply #21 on: July 13, 2011, 07:33:53 AM »

This horse is probably long since beat to death, but...

Using your analogy, why not just use dipoles, and forget about a beam? The reasoning should be obvious.

My analogy was questioning your "The only thing that counts is band conditions between two points. Nothing more, nothing less" statement.

Of course the reasoning is obvious. One gives a greater ERP than the other, among other advantages.  It is not "only" band conditions. Most people understand that.

But I thought we were discussing mobile antennas.


Mobile antenna "A" setup, 70% efficient, is going to put whatever band conditions there are to better use than mobile antenna "B" setup that is only 30% efficient. The reasoning should be obvious.
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W5DXP
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« Reply #22 on: July 13, 2011, 08:17:28 AM »

If I can get decent performance on 20 meters and up I'll be satisfied. 

Since 20m is a wavelength, "20m and up" would be lower in frequency. Smiley (The devil made me do it.)

I have done both and couldn't tell a lot of difference between an auto-tuner driven whip and a screwdriver on 20m-10m. As you suggest, the big difference happens on 40m and especially on 80m where the screwdriver was ~12dB better than the whip plus autotuner.

http://www.w5dxp.com/shootout.htm
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73, Cecil, www.w5dxp.com
The purpose of an antenna tuner is to increase the current through the radiation resistance at the antenna to the maximum available magnitude resulting in a radiated power of I2(RRAD) from the antenna.
N6AJR
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Posts: 9879




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« Reply #23 on: July 13, 2011, 11:20:18 AM »

Heck, IU can do the switch test easily here in the shack.  I have 4 different antennas that work on 20 meters, a 3 ele steppirat 33 feet, a sloper at 33 feet, a gap voyager and a hustler 5btv.

I can switch between antennas with the click of a switch. Most of the time the steppir has the best recieve and  transmit. next is usually the gap voyager, then the alpha-delts sloper, and then the hustler 5btv. Notice I said Usually, some times the 5btv has the best results, I think it is due to take offf angle. most of the time th sloper and the gap are about even, but some times the gap hears better than the  steppir. Again I think it is either take off angle or polorization.  Perhaps it is also dependent on capture area, which is very important on mobile antenna. 

So yes they antenna makes a big difference, along with the take off angle, propagation, capture area, size and local ground conditions ( on a beach near the ocean, on a peak of a 6,000 foot mountain, or in the middle of a big city.  most every thing has a bearing.
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W4FID
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« Reply #24 on: July 14, 2011, 03:37:04 AM »

First accept that propagation -- not the antenna -- will be the primary determining factor. Some days great propagation allows nice QSOs with a poor antenna. Some days with poor propagation a great antenna is still not effective. That's beyond your control -- so set your expectatins realistically and enjoy who you work when you work them.

I believe the single most important thing you can do is a great "ground". Mechanical mount to as much as good as you can to the car's metal. Straps between as many "sections" of the car as possible. A car has sections that have rubber shock mounts between them for noise and vibration reduction -- but that means electrically your car is a bunch of smaller metal parts and you want as much mass/area as you can. The metal in your car is a capacitor plate that couples to the earth for your RF ground. Bigger plate closer to the pavement is a beter capacitor -- hense everyone's advice to have the car's chassis or floor pan well connected to the "ground" side of the antenna mount. A mag mount is not in the same league.

I had a screwdriver and it was fine. But it still has most of the length and the high current part of the radiator in a coil at the base. So do "hamsticks" (various manufacturers with their own names). So the effectiveness is about the same. But a few hamsticks on quick disconnects is WAY less cost and less mechanical stress due to less weight and diameter. Also you could debate the safety of adjusting the screwdrivew while driving. That's why I said I had one -- but don't now. Scared myself a few times. And if you tune it while stopped why not just swap sticks? I pick a band I think I'll enjoy when I leave based on expected band conditions and nets I like etc. After a while I stop to pee or get a coffee or gas and maybe swap bands. Works well. I have sticks for 40 -20 -15 -10 which cover the entire general class portions of the SSB sections at under 2:1 SWR at about 20% of the cost of a screwdriver. Also CHECK IT OUT -- the mount for some screwdrivers is NOT a 3/8-24 like most ball mounts are (you mentioned a ball) so check first and buy second.

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K0BG
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« Reply #25 on: July 14, 2011, 06:40:12 AM »

Well, that's why automatic antenna controllers are such neat devices. Push the tune button on the microphone, and let electronics do the rest.
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N6AJR
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« Reply #26 on: July 14, 2011, 01:24:09 PM »

yup and several of the Yaesu's come with a built in controller for the ATAS antennas. I think the 857, the 897 for sure and perhaps the 847 . change bands or freq's and pushh the tune button. done.
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