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Author Topic: 43 foot verticals  (Read 10652 times)
WX7G
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« Reply #30 on: December 04, 2012, 04:44:37 PM »

43' vertical article

http://www.eham.net/articles/21272
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WB6BYU
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« Reply #31 on: December 04, 2012, 05:20:25 PM »

And here is VK1OD's analysis of losses:

http://vk1od.net/antenna/multibandunloadedvertical/index.htm

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K0OD
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« Reply #32 on: December 06, 2012, 05:48:37 AM »

The poster who bashed the performance of these verticals on 40 has disappeared.

Links in the previous two posts suggest that 43 foot verticals have ESPECIALLY low losses on 40 meters unless fed with extremely long runs of poor quality feedline.  

Mine is 30 feet from my one-story home. I've used it for DXing, contesting and rag chewing for 4 years now. Using a 43' vertical solely for 20 meters is a waste of an antenna that's quite competent on 60 thru 15, and decent even on 80 and 10-meters.
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W5DXP
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« Reply #33 on: December 06, 2012, 06:10:31 AM »

Links in the previous two posts suggest that 43 foot verticals have ESPECIALLY low losses on 40 meters unless fed with extremely long runs of poor quality feedline.  

A 43' vertical has a feedpoint impedance of around 100+j200 on 40m. A base-mounted autotuner, like my SG-230, would have very low losses with that feedpoint impedance and provide minimum (matched line) coax losses. It's hard to beat an autotuner at the base of these non-resonant length verticals.
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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.
K0OD
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Posts: 2532




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« Reply #34 on: December 06, 2012, 07:04:51 AM »

A remote tuner is a very pricey way to go for hams running >100 watts. At least the cost is coming down. I've given it some thought. I'm not comfortable leaving such an expensive item outside. Also, I've heard plenty of complaints about the durability of remote tuners. OTOH, my in-shack Dentron MT-3000 is going strong after 35 years.

On 160 a remote tuner would be a huge benefit (on transmit only) , but so would clipping on a simple wire top hat or "L" wire. On bands higher than 80, the advantage of a remote tuner is negligible if the feedline is short.   

Any thoughts on this new remote tuner from MFJ? 
http://www.dxengineering.com/parts/mfj-998rt
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STAYVERTICAL
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« Reply #35 on: December 06, 2012, 12:53:46 PM »

+1 for a remote base mounted tuner.

Put it in a waterproof case, and it will last indefinitely.
Even so called weatherproof tuners will benefit from this treatment.

I have used remote ATU's for seven years and sometimes I have to replace the case I enclose them in, but never the tuner itself.
Even some retrofitted remote tuners I have modified from coax type tuners are not a problem.
If you fit them in a watertight case, they will last as well as being in the shack.

I recently took one in for a basic clean, and it did not look any different to a new one I had recently acquired.
So, don't settle for the case it came in, give it an extra layer of protection and it will last a long long time.

The days of having to battle SWR losses on feedline coming from a multiband vertical antenna should have been left behind many years ago.
The VK1OD link which 6BYU gave shows that feedline losses are a major player in system losses with this type of multiband vertical.
These can be eliminated with a remote antenna tuner, so gaining you many dB which would otherwise have to be provided by an amplifier.

Remote ATU's are not that expensive these days, and it is hard to overstate the benefit of pressing the button and having a low feedline SWR.
I read time and time again about hams having matching nightmares, when it could be so simply and efficiently solved.
In addition, a good remote ATU can be used with open wire feedline to other types of antenna's, so they are extremely versatile.
We can then concentrate on the antenna, and forget the matching nightmares.

73 - Rob
« Last Edit: December 06, 2012, 01:13:43 PM by STAYVERTICAL » Logged
KE2TR
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Posts: 130




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« Reply #36 on: December 06, 2012, 06:04:49 PM »

I will end up tunning it just for 20 and let it be.

You can improve the 20m efficiency by installing a matching network at the base - probably just a tapped loading coil.
I used 8 turns of #12 around a 2" form about 1.6" long at the base and a balun design 4:1 Unun, loads on 20 mtrs. with a 1.2 swr at 14.2mhz and 1.5 at band edges. I did shorten the vertical down to 41.5' which would be 5/8 on 20 at 14.2mhz, it still loads on 75 with the tuner in line but a 35' inverted L with 2 gull wing radials spanks it on that band but it realy does well on 20 mtrs (there's a bunch of radials in the ground and added some 20 mtr radials as well).
Jim
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KE2TR
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« Reply #37 on: December 06, 2012, 06:18:22 PM »

I have two 1/4 wave verticals up for 40mtrs and I have removed one just to compare with the 43' vertical, the monoband vertical is always 6db  better on tx and sometimes more of rx. Sorry my real world comparo's speak volume from what I have seen and it always shows up on DX but on 20 it kicks some but. BTW the two 40mtrs vertical array is12-15db better on everything, tx&rx. Makes me think what two would do on 20!
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WD4ELG
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« Reply #38 on: December 07, 2012, 04:00:15 PM »

Thanks for posting those results.  Definitely expect 2 x verts phased over single 43 to be better.

Wondering about 20 meters, where a directional horizontal antenna should blow the verticals right off the map.  However...it would be interesting to see....since the vert would be very low angle of radiation...and the horizontal antenna would need to be very high (above half wave) to get that...plus up higher the horizontal antenna would have secondary lobes at higher angles (which is why the big guns phase them...to eliminate those higher lobes).
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KA7NIQ
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« Reply #39 on: December 07, 2012, 10:13:34 PM »

Here in Florida, you see an awful lot of these 43 foot S9 Verticals, mounted on chain link fences w/o any additional radials. The fiberglass S 9 Verticals seem most popular, because some Hams here in Florida have power lines nearby.
They seem to do ok with these antennas, especially on 20 and 40 meters.
One Ham I know has one of these mounted where 4 chain link fences come together.
He used the MFJ current sensing meter to make sure his chain link fences were seeing the full current they should have, and had to electrically enhance (bond) some parts of the chain link fence. He uses an LDG high power auto tuner at the base of the antenna.
He only has a small amplifier, but on 40 meters, well inland from any salt water path, he blows smoke into Italy on 40 meters at night. All from a smallish city lot, east of Tampa.
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K0OD
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Posts: 2532




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« Reply #40 on: December 08, 2012, 05:11:27 AM »

If a 43 footer works terribly on 40 meters, something else is going on.

It's hard to follow your antenna tests or know when they were conducted. Likely there's some interaction between the multiple 40 meter verticals you're comparing. Certainly your 1/3 acre QTH, with NINE yagis on two towers, isn't exactly a pristine antenna test range:

http://lists.contesting.com/_towertalk/2001-09/msg00034.html
http://www.ezoom.net/images/lotsayagis.jpg
http://www.qrz.com/db/KE2TR.
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AD5X
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Posts: 1426




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« Reply #41 on: December 08, 2012, 09:02:35 AM »

...Any thoughts on this new remote tuner from MFJ? 
http://www.dxengineering.com/parts/mfj-998rt

I did the review on the MFJ high power remote tuners for QST.  The unedited review is in the "Reviews" section on my website at www.ad5x.com.  After returning the tuners to the ARRL, I decided I really wanted one for my 43-footer.  So I got one.  I could have gone with the much less expensive MFJ-994BRT since I just run 500 watts, but I chose the MFJ-998RT since it is so much more "hefty".  R&L has the best prices I found.  Anyway, all tuners worked fine for me.  The only issue is that none of the remote tuners can tune the 43-footer on 160 meters without adding external inductance (see November QST or the 160M extender article in the "Articles" section of my website)

Phil - AD5X
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K0OD
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Posts: 2532




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« Reply #42 on: December 08, 2012, 07:08:26 PM »

Hey Phil I was reaching for my credit card when I noticed that very costly MFJ-998RT KW remote tuner is spec'd to handle SWR's only under 32 to 1. 43 footers have SWRs much greater than 100:1 on 160 and perhaps more than 32:1 on 80.
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AD5X
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« Reply #43 on: December 08, 2012, 07:42:20 PM »

Hey Phil I was reaching for my credit card when I noticed that very costly MFJ-998RT KW remote tuner is spec'd to handle SWR's only under 32 to 1. 43 footers have SWRs much greater than 100:1 on 160 and perhaps more than 32:1 on 80.

It'll tune the 43-footer on 80 meters, but not on 160 meters.  See my article in the Nov QST, or in the "Articles" section of my website that shows my add-on inductor for 160 meters.

Phil - AD5X
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K0OD
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« Reply #44 on: December 08, 2012, 08:30:59 PM »

Yes, I'm familiar with your excellent material. I've used a properly baseloaded 43' vertical on 160. Frankly, it's a lot of work and cost and the result still isn't good on 160. Using 100 watts, I eked out a few Qs with big gun European stations. Now without the baseloading, Qs beyond 1,000 miles were nearly impossible.

I had much better luck with a wire L years ago: 140' of wire tossed over a 50 foot tree with the end anchored to another tree. Cost about $5 and was invisible. I understand that not everyone can get a wire up 50'.  
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