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Author Topic: 33 Ft. 40m Vertical  (Read 21153 times)
W8JX
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« Reply #15 on: July 30, 2011, 09:06:34 AM »

I answered a question hoping to receive a remedy or solution. Thank you

A vertical likes to be at least 1/4 wave away from metal that could possibly resonant or effect antenna performance. House it full of electrical wire. All the radials in the world is not going to help much next to house. How about roof mounting it?
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N3OX
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« Reply #16 on: July 30, 2011, 09:35:49 AM »

If you get 20-40 radials in that 20x40 foot space that's actually pretty okay for 40m.

Unfortunately, I have to agree with the others that moving the vertical away from the house will probably give the biggest performance boost of anything.   If you feel that the vertical is weak on transmit or noisy on receive, that is probably going to make the biggest difference of anything you can do.

The hexbeam itself and the vertical won't interact much.  Being 10 feet from the the hexbeam mast wouldn't be great for the vertical, but I think if you could put the vertical in the middle on the fence side it probably would work better, even though that puts it somewhat closer to the mast in the upper right corner.



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

Monkey/silicon cyborg, beeping at rocks since 1995.
AD5MD
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« Reply #17 on: July 30, 2011, 10:01:49 AM »

Don,

That makes sense but unfortunately I won't be able to move the vertical from its present location.  The remaining space in the backyard will be used soon so moving and taking it out later will be useless.  I guess adding more radials and see what the difference will be would be most I could do at the moment.  Otherwise I'll just wait 'til I put up a free standing tower and string a dipole.  Tnx very much
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W8JX
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« Reply #18 on: July 30, 2011, 11:39:56 AM »

Don,

That makes sense but unfortunately I won't be able to move the vertical from its present location.  The remaining space in the backyard will be used soon so moving and taking it out later will be useless.  I guess adding more radials and see what the difference will be would be most I could do at the moment.  Otherwise I'll just wait 'til I put up a free standing tower and string a dipole.  Tnx very much

Personal I would not waste anymore time or radials with that antenna next to house.  A full sized 1/4 wave vertical is a good antenna. You just then to move it either away from house or on top of it.
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AD5MD
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Posts: 29




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« Reply #19 on: July 30, 2011, 11:51:10 AM »

Making more researches now I am planning on just home brewing a pancake antenna and install it at 20ft on the same spot where the vertical is.  If that works, the vertical will be either up for sale or kept for future use.
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W8JX
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« Reply #20 on: July 30, 2011, 12:33:37 PM »

Making more researches now I am planning on just home brewing a pancake antenna and install it at 20ft on the same spot where the vertical is.  If that works, the vertical will be either up for sale or kept for future use.

I have used a Hustler 5BTV vertical for close to 20 years and it has always performed well on 40 and it is not fullsized either but it is located well away for house.
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N3OX
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« Reply #21 on: July 30, 2011, 01:23:30 PM »

Making more researches now I am planning on just home brewing a pancake antenna and install it at 20ft on the same spot where the vertical is.  

Many of those types of antennas, especially the tiny ones (http://www.para.org.ph/membersarticles/Pancake%20Antenna/) just end up being a way to top feed the coax shield and/or mast, making it a vertical as tall as the mast.  As such, it will probably work the same as your vertical.  If it works like it looks, just a little short end loaded dipole, it's too short for 40m.  The much bigger ones would be better as a self contained antenna, but you'd want something maybe 15-20 feet long between the spirals minimum.

I guess your vertical is giving disappointing performance if you're looking to replace it with something like that?  Is it too noisy or what?  

Is it manmade noise if so?

Certainly, whenever you're really constrained, experimentation is a good idea so you might just want to try things and see what sticks.  
« Last Edit: July 30, 2011, 01:31:55 PM by N3OX » Logged

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

Monkey/silicon cyborg, beeping at rocks since 1995.
AD5MD
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Posts: 29




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« Reply #22 on: July 30, 2011, 01:43:09 PM »

Dan,

I've been reading about the pancake and so far I'm not totally convinced about it.  It just came as a thought of an alternative antenna.  Incidentally, the link that you posted is from a friend from DU where I'm originally from, hi.

The noise is I'd say between S6 to S8 at night and right now (0338 CST) it is at S5 but I don't hear anyone at this time, must be the propagation.  I've worked stations from HA, LZ, I, SM, PY on both ssb and cw though so not really that frustrating, hi.  It could just be the propagation I suppose?  Oh well, I still have a spool of 250ft of aluminum electric fence wire here so maybe I'll gamble and try to lay down some more radials.  Tnx

Ernie
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K9ZM
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« Reply #23 on: August 01, 2011, 06:40:53 PM »

I don't know if if will help you, but you can see mine at QRZ.  I have added more radials to a total of 44.  It's in a side yard, so space is tight.  But I had plenty of room for 20 1/4 wave radials and added 22 more with some as short as 6ft and some 1/4 wave long.  It's not always the best choice for a close in antenna.  But it gets the job done.  At times it's like magic it works so well.  It works DX.  I have ST0R on both 40 and 30m with it.  The FT-2000D tunes it for 30m just fine. 

For reception, if noise seems to be a problem, I use the RX antenna port and use the Force12 C3E as a receive antenna.  I have an ICE RX antenna port protection box.

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W8JI
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« Reply #24 on: August 02, 2011, 04:01:12 AM »

I want to point one thing out people miss. We really need to nip this myth about SWR and bandwidth in the bud and **stop repeating it**.

Base impedance and SWR bandwidth of an antenna by itself tells us next to NOTHING about efficiency. Narrowness of bandwidth by itself tells us virtually nothing about efficiency. Feed resistance also tells us nothing universally definitive about losses.

It would be best to IGNORE all the wild projections about efficiency of your vertical that are based on unreliable pretty much meaningless data like feed efficiency, SWR, and bandwidth. They can never be more than the wildest of guesses. It's sounds like expert theory and advice to say "you have 51.0 ohms base impedance and it should be 36.259 ohms, so you have 14.741 ohms loss resistance"  or "only dummy loads are 300 kHz wide" but none of that really relates to losses or efficiency.

73 Tom







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W3WN
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« Reply #25 on: August 03, 2011, 12:18:10 PM »

Two words:  Add radials

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N2EY
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« Reply #26 on: August 03, 2011, 12:52:51 PM »

its performance is marginal. 

What does "marginal" mean to you?

What do you want the antenna to do - DX, stateside ragchewing?

I agree that being so close to the house is a big problem. What sort of construction is the house? Stucco? Aluminum siding?

73 de Jim, N2EY
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W8JX
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« Reply #27 on: August 03, 2011, 01:35:47 PM »

Two words:  Add radials

It has a bigger problem than lack of more radials. Its caused by back off house 5 foot from it. No amount of radials is going to fix this.
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W5DQ
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« Reply #28 on: August 03, 2011, 01:41:08 PM »

I find it interesting that many say that a 33 ft 40M vertical is a poor performer. I have a 33 ft (appx) 40M vertical with thirty 40M 1/4 wave length radials on the ground plus 3 extra radials appx 50-65 ft long in the mix. The anttenna is tuned to cover 7.0 to 7.2 with a 1.5:1 SWR at the edges and roughly flat at midpoint. I feed it with 50-60 ft of 9096-IIA low loss air core without a tuner and have 12 RG-213 sized split ferrite blocks (roughly 1.25" square) at the feed point. The antenna tubing is 1.5" at the base and tapers up to 3/4" at top. There is no cap hat although it was suggested to me to use on to improve the performance and bandwidth. Not sure if that is a fact or fantasy as I haven't modeled it nor tried it. The antenna easily handles up to 600W as I use a AL-811 to drive it with no problems.

As far as performance, I have had very good success with this vertical on DX into all areas of the world. It is mounted appx 60+ ft from any buildings and next to a fence. Only issue I have noticed is when my neighbor moved his converted Greyhound type bus next to fence about 10-15 ft from antenna. Everything went squirrelly for a bit until I figured it out. Since then he has moved the bus and all is back to normal or what I call normal.

Curious what others might suggest to make this a better performer although I find it currently great?

Gene W5DQ

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Gene W5DQ
Ridgecrest, CA - DM15dp
www.radioroom.org
W8JX
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« Reply #29 on: August 03, 2011, 03:15:37 PM »

It is best to have a Vertical at least 1/4 wave away for house and metal structures. Further is better still.  Being that close to house and wiring in it I imagine is radiation pattern is pretty squirrely. Take any good antenna and mount/install it wrong and it will not work well.
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