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Author Topic: Antenna - Vertical or Dipole? Inverted V?  (Read 23292 times)
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kc0jez
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« on: June 11, 2009, 01:13:16 PM »

Still need to whip up an antenna too, first HF antenna for me since the 70's.

I have many options, none optimal near as I can tell.  Last HF antenna I put up was a 40 meter dipole in 1972! Been on VHU/UHF last 10 years of so, getting back into HF on AM!

I can put up a 40M dipole. Yard is just long enough, but it would be passing by the house for most of it's length, about 1-2 feet from the house, and only about 15 feet from ground.  I could go with an inverted V cut for 40 with the top about 30 feet from ground, and each sloping along the side of the house, again about a foot or so away from the house.

Then, I was looking at the Hustler 4-BTV vertical which is suppose to be good on 10, 25, 20 and 40 meters. Their literature seems to indicate you can make this work with or without radials. One of their options is ground mounted with no radials, or with. I *could* do that, but again it would be close to the house, or in the one spot further from the house (but not much further) it would be very close to power lines.  However, I CAN easily mount this ON the house.  I presently have a mount at the top of the house at an attic window securely bolted to the framework of the house.  This would put the base of the antenna 3 stories from ground -- probably 30 feet or so -- with the antenna going up 21 feet from there in free space, clear of the house. Presently there is a two meter beam and rotator there which I am taking down, so easy to mount, and there's a already a fresh run of RG-8 going up there and to the shack. So that seems the easiest and highest option I have. However, this would leave virtually NO chance of any radials from the antenna however it would be quite easy to run a stout cable to a ground rod (or two) directly below the antenna.  I have 8 (maybe 10.. don't remember) foot long ground rods already installed right below where this antenna would mount. Would this be a good/bad somewhat viable option?  I have NO HF experience with a vertical antenna.  Would this also be acceptable for receiving?  Trouble is, I'm in a small town, on a long city lot with a BIG house on it, so there's room to run an east-west dipole but little to hang it on. And it would be close to the house.

In case you didn't catch my other post.. I'm setting up a vintage Heathkit station with a DX-60 and HR-10 for AM work. I DO plan up upgrading to better gear as time goes on, but this is what I've got at hand for now.

Thoughts?
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« Reply #1 on: June 11, 2009, 01:49:48 PM »

 If it was my place, I'd go with open wire feeders, center fed, with a  tuner.
 
Based on what you want to do, I'd go with a "v".......

If  yer going to , put it up as high as you can; don't worry if its a true V. If one end is higher than the other, no problem. Try to keep stuff as far from the house as you can.

Check out the antenna section here on amfone.


klc

 
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N3DRB The Derb
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« Reply #2 on: June 11, 2009, 02:07:49 PM »

dont ever believe anyone that says you can use a ground mounted vertical like the hustler without a LOT OF ground radials. It's not so.

Now, put that vertical on your roof, with 3 or 4 tuned wire radials for each band, and it will perform pretty well. The ground rod wont do a thing for you. You have to have a RF ground plane under the base of that antenna. put it off the ground, and you can use a few wires per band as opposed to 130+ with it on the ground.
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k4kyv
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« Reply #3 on: June 11, 2009, 02:15:05 PM »

Then, I was looking at the Hustler 4-BTV vertical which is suppose to be good on 10, 25, 20 and 40 meters. Their literature seems to indicate you can make this work with or without radials.

And I have a bridge for sale, cheap, located in Brooklyn, NY.

Or maybe they have discovered how to by-pass the laws of physics.

Any ground-mounted vertical needs a radial system, unless you want to expend 80-90% of your rf energy warming the earthworms.

Quote
However, I CAN easily mount this ON the house.  I presently have a mount at the top of the house at an attic window securely bolted to the framework of the house.  This would put the base of the antenna 3 stories from ground -- probably 30 feet or so -- with the antenna going up 21 feet from there in free space, clear of the house... However, this would leave virtually NO chance of any radials from the antenna however it would be quite easy to run a stout cable to a ground rod (or two) directly below the antenna.  I have 8 (maybe 10.. don't remember) foot long ground rods already installed right below where this antenna would mount.

Putting the vertical on the roof may be the best option.  You would then be able to use an elevated counterpoise, or radial system, and you could get away with a lot fewer radials than ground mounted.  If you have a metal roof, the roof itself might make a good ground plane.  Otherwise, some radial wires could be laid out inconspicuously along the surface of the roof.  At 30 ft., the ground plane would be a quarter wave off the ground, so a few radials should work quite well.  If you run a ground wire straight down to some ground rods, all you will have will be a taller ground-mounted vertical with no radials.  That might actually work better, but you still need radials at the ground point, not ground rods.  Ground rods work well at 60~ a.c. and to bleed off static discharge, but are virtually ineffective as r.f. grounds.

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kc0jez
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« Reply #4 on: June 11, 2009, 02:18:58 PM »

dont ever believe anyone that says you can use a ground mounted vertical like the hustler without a LOT OF ground radials. It's not so.

Yes, this is what I have always believed.  Which is why I was a bit perplexed because it's the manual for the antenna that says you can use it ground mounted to a 4 foot rod pounded into the ground to mount it on, without radials!  I figured the people that make them, must know, but I was skeptical. Hence my theory that the same antenna, on the house, with a ground, would work similarly. My problem is, my house mounting option actually puts the antenna on the side of the house, at what is generally called a dormer window, with no roof under it for radials to go.

Now, put that vertical on your roof, with 3 or 4 tuned wire radials for each band, and it will perform pretty well. The ground rod wont do a thing for you. You have to have a RF ground plane under the base of that antenna. put it off the ground, and you can use a few wires per band as opposed to 130+ with it on the ground.

I don't have the manual in front of me, but there was something about the use of radials in a roof mount to create a ground plane that *appeared* to be stiff radials that were rigid and would protrude outward 90 degrees from the base? this I could do but only on 180 degrees of the base on the side away from the house.

I'm thinking the inverted V is going to be my answer.

Tim in Bovey
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kc0jez
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« Reply #5 on: June 11, 2009, 02:30:13 PM »

Then, I was looking at the Hustler 4-BTV vertical which is suppose to be good on 10, 25, 20 and 40 meters. Their literature seems to indicate you can make this work with or without radials.

And I have a bridge for sale, cheap, located in Brooklyn, NY.

Or maybe they have discovered how to by-pass the laws of physics.

Any ground-mounted vertical needs a radial system, unless you want to expend 80-90% of your rf energy warming the earthworms.

Quote
However, I CAN easily mount this ON the house.  I presently have a mount at the top of the house at an attic window securely bolted to the framework of the house.  This would put the base of the antenna 3 stories from ground -- probably 30 feet or so -- with the antenna going up 21 feet from there in free space, clear of the house... However, this would leave virtually NO chance of any radials from the antenna however it would be quite easy to run a stout cable to a ground rod (or two) directly below the antenna.  I have 8 (maybe 10.. don't remember) foot long ground rods already installed right below where this antenna would mount.

Putting the vertical on the roof may be the best option.  You would then be able to use an elevated counterpoise, or radial system, and you could get away with a lot fewer radials than ground mounted.  If you have a metal roof, the roof itself might make a good ground plane.  Otherwise, some radial wires could be laid out inconspicuously along the surface of the roof.  At 30 ft., the ground plane would be a quarter wave off the ground, so a few radials should work quite well.  If you run a ground wire straight down to some ground rods, all you will have will be a taller ground-mounted vertical with no radials.  That might actually work better, but you still need radials at the ground point, not ground rods.  Ground rods work well at 60~ a.c. and to bleed off static discharge, but are virtually ineffective as r.f. grounds.



Hmm.... again, I'm cursed with a rather narrow band of yard alongside the house.  If the antenna is on the side of the house, at the attic dormer window, it's about 30 feet off the ground. If I ran a ground from the mount to the ground rod below it, and then added radials to the ground would that be feasible? Again, I could only put radials over 180 degrees, but they could be quite long at angles to the left and right, but would have to be quite short the closer I get to 90 degrees from the house.  there's probably 10 feet between the house and the neighbors fence. Hey- would their metal fence make a nice ground plane? (always thinking creatively).

Oh, our house is shaped weirdly with sort of a very steep pyramid roof with an attic dormer window on each side and no way to really get on the roof itself without hiring a daredevil. So getting radials from where I can mount, ON to the roof is not possible.

Tim in Bovey
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Steve - WB3HUZ
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« Reply #6 on: June 11, 2009, 02:34:27 PM »

Why not put up both? The dipole will be better for shorter distance stuff, especially on 40 meters, and the vertical better for the longer distance contacts.

Don't bother with radials at the ground rod if the vertical is up on the roof. Could you get the radials up on the steep part of the roof by tying small weights on the ends and tossing them up where you want/need them?
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kc0jez
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« Reply #7 on: June 11, 2009, 06:12:12 PM »

Oooohh.. here's something!  As I was standing in the yard analyzing the possibilities....I hadn't considered the garage! We have a single car attached garage at the back of the house. Peaked roof. I have a spare tripod mount.  I could mount the Hustler on this, and then have the ability to run some radials on the garage roof.... although being a single car garage length is limited...  but again, in some directions I'd be going lengthwise and long/diagonal.

What sayeth the gurus? Better than a dipole or inverted V? More flexible for varying bands? I'm not expecting killer DX with a DX-60, but it would get me started.  How do these antennas work for receiving? Also, if I go with the garage I'm going to wind up running another 20 feet of coax, but I suspect that's not too critical?

Continuing to brainstorm.

Tim in Bovey
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K1JJ
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« Reply #8 on: June 11, 2009, 06:37:54 PM »

Hi Tim,

The vertical and dipole do two different jobs and complement each other well. Do both, if you can.  The vertical is vertically polarized and generally low angle. (If you have a good radial system and the general area is clear of obstructions)  The dipole, below 1/4 wave above ground is generally a high angle radiator and horizontally polarized, good for local work. They can vary in strength locally up to 40db. Huge difference.

A dipole with flat legs, straight and as high as possible is always better than any form of inverted vee or zig-zagged derivation.  The more the legs come together, the more the radiation is canceled, until it is fully canceled when the legs are fully folded together. (becomes a transmission line)   The maximum angle to bring the legs together in inv vee fashion is about 90 degrees before it starts to really hurt performance. As for the vertical radials and your comment above... laying out radials is only for reducing ground losses. Cover all the area, as much as possible. Radials have little to no effect on pattern formation, so laying them out longer to favor certain directions is for naught. At least that's what the 160M corntest vertical gurus have told me. I bet modeling will back that up. Here's a summary about radials that should help you.

http://amfone.net/ECSound/K1JJ16.htm


BTW, make sure your dipole feedline is far away from the vertical itself or mutual coupling may occur. This can be tested by and suspected if the two antenas perform about the same during A/B tests. Another test is to put 100w into the dipole and then put a wattmeter and dummy load on the coax end of the vertical. You should see no more than 1 watt on the wattmeter (-20db of isolation) or else the coupling is unsatisfactory.

You want the two antennas to complement each other under different conditions by being isolated and optimized for different jobs. Coupling causes them to share their characteristics, acting like one antenna.

Good luck!

Tom, K1JJ

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« Reply #9 on: June 11, 2009, 07:41:11 PM »

Another advantage to having both a dipole and vertical up is that you can get a phasing noise canceling box (they're made by Timewave, DX Engineering, MFJ) and use the vert. as a  noise pickup antenna when you're on the dipole and null out the noise.  If you're in town and you have some electric blanket or cell phone charging supply or some other garbage generator nearby this is a nice way to null it out.

The vert. up on the garage may be a good thing.   Elevated radials don't have to be 90 degrees off the vertical.  If I were putting up a high band vertical I'd mount it on a 15 foot pipe and bring the radials down all around at different lengths for the high bands, to earth screws keeping the wires tense and 45 degrees from the mast.

this is in no way directed at anyone here--I just want to relate a typical conversation I have once in a while with hams who are in denial about the need for a ground system:

Other ham:  I just put  up a new vertical; quarter wave on 40 meters.

Me:  Oh yeah?  how many radials did you put down?

OH:  None.  you don't really need them.  I have a ground rod.  And I get 10, 20 over 9 reports.

Me:  How much power are you running?

OH:  1500 watts.

Me:  What's your amp?

OH:  <At this point he gives some model that has a tube or tubes with at least 1500 watts dissipation, telling me he's running at least 1.5 Kw and probably more.>

Me: You know, with 30 to 60 radials on 40 m. with that much power you'd be at least 40 dB over S9; you'd be 10 or 20 over 9 with 100 watts.

OH:  I get out.  I don't need radials.

What every hams learns eventually (or maybe not) is that you can take a pie pan and if you ram enough power into it, you'll get out and have 59 reports.    There's a mental hurdle with radials--it is so seemingly counter intuitive to take a  lot of wire and....<i>lay it on the ground</i>.   That can't work!  But it does.  There are a few other things like it: ferrite cores, ladder line -- they all seem like a sham until you try them and find they work. 

73

rob / k5uj
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« Reply #10 on: June 11, 2009, 09:25:40 PM »

Don, I sold you that bridge in 1959 when I left Brooklyn, how come you still have it? Dont you remember? It included the Gotham vertical which required no radials Roll Eyes

Carl
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« Reply #11 on: June 11, 2009, 09:44:37 PM »

Yes, the Gotham vertical.

In 1964 I bought one from Corky at Hatry's in Htfd, CT, used for about $12. I mounted it on a steel pipe, 3' away from the side of the house w/o radials and called CQ for 3 days with no replies on 3716kc CW. My first days on the air. I stopped writing CQ's into the log cuz it was filling up. I brought it back to Corky and he axed me where I got that piece of crap. (He forgot he sold it to me a week before)   Corky showed me how to make a coax pigtail and I put up a 40M dipole. Worked all over the country that night and was in utter shock.

When I first put it up I stood there marveling at what a great antenna it looked like. I tried to cornvince my dad to buy 1000' of coax so I could mount it on a tree and run, get this, FIVE coaxes back to the shack for the various bands, all connected to the coil at the same time. I had no clue to what the term "stubs" meant.


Years later my buddy bought a Gotham Yagi.  He said he started assembling it and it was so flimsy and poorly made he stopped and used it as support poles for wire antennas instead.... Grin

Funny thing is, if the Gotham vertical was installed properly, in the clear with a great radial system, it would work just as well as any shortie vertical.  It's all in the implementation of the device.   Most of us as JN's had no clue and suffered the consequences... :-)

T


* GothamVertical3.jpg (161.68 KB, 894x1169 - viewed 2383 times.)

* GothamVertical.jpg (121.63 KB, 850x1296 - viewed 1057 times.)

* Gotham2.jpg (176.41 KB, 850x1303 - viewed 939 times.)
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« Reply #12 on: June 12, 2009, 07:42:32 AM »

Don't bother with radials at the ground rod if the vertical is up on the roof. Could you get the radials up on the steep part of the roof by tying small weights on the ends and tossing them up where you want/need them?

I actually did that many years ago, and it worked fairly well on the higher bands. (10, 15, and 20). However, a friend gave me another idea to try, he had been using one like that for years: Mount the vertical on top of a chain-link fence! Voila.....instant ground plane!!
I tried it just for the hell of it and it did actually work. Who'd of thunk!

or try this...........

                                                               the Slab Bacon

* short ant.pdf (483.04 KB - downloaded 328 times.)
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Steve - WB3HUZ
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« Reply #13 on: June 12, 2009, 08:45:08 AM »

As the ad sez, "You could work wonders with a Gotham vertical."  But you won't work any other stations!


Yes, the Gotham vertical.

In 1964 I bought one from Corky at Hatry's in Htfd, CT, used for about $12. I mounted it on a steel pipe, 3' away from the side of the house w/o radials and called CQ for 3 days with no replies on 3716kc CW. My first days on the air. I stopped writing CQ's into the log cuz it was filling up. I brought it back to Corky and he axed me where I got that piece of crap. (He forgot he sold it to me a week before)   Corky showed me how to make a coax pigtail and I put up a 40M dipole. Worked all over the country that night and was in utter shock.

When I first put it up I stood there marveling at what a great antenna it looked like. I tried to cornvince my dad to buy 1000' of coax so I could mount it on a tree and run, get this, FIVE coaxes back to the shack for the various bands, all connected to the coil at the same time. I had no clue to what the term "stubs" meant.


Years later my buddy bought a Gotham Yagi.  He said he started assembling it and it was so flimsy and poorly made he stopped and used it as support poles for wire antennas instead.... Grin

Funny thing is, if the Gotham vertical was installed properly, in the clear with a great radial system, it would work just as well as any shortie vertical.  It's all the implementation of the device.   Most of us as JN's had no clue and suffered the consequences... :-)

T
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« Reply #14 on: June 12, 2009, 10:14:39 AM »

As the ad sez, "You could work wonders with a Gotham vertical."  But you won't work any other stations!

HAHA! "wonders" why nobody ever answers you?!
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« Reply #15 on: June 12, 2009, 12:36:04 PM »

As the ad sez, "You could work wonders with a Gotham vertical."  But you won't work any other stations!


"Even the 'price is no object customers' choose Gotham antennas based on performance and value."  (choke-gag)


It would be a scream to put up a perfectly installed set of four Gotham vericals in a 4-square for 75 or 40M.  I'll bet it would kick ass with a full radial field and 1/2 mile of clearing around them.    As a complement to it, a G5RV at 120' high, stretched flat between two towers would be just as effective.  The DX guys wouldn't believe you.

I don't think there's much that can be done with an Isotron, however... Grin  (The NASA shirt and rug helps)


* Isotron_40-80.jpg (138.57 KB, 613x900 - viewed 1042 times.)
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K8WBL
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« Reply #16 on: June 12, 2009, 02:22:10 PM »

I will throw in my 2 cents, been playing around with home brew antennas and commerical verticals for years.  In the midwest vertical dont seem to do well, depending on soil - YOU WILL NEED a GOOD RADIaL system... sure it will work without a good one but radiation effeciency will suffer badly.  I have had nearly every vertical from the Gotham vertical, R-5, 18AVT, butternut and finally the KING of all verticals, the Hygain Hytower....my dipole and loops beam them all.  Partically for state side contacts - hands down.  The half wave verticals that are mounted up and clear of buildings seem to do best, such as the Gap Titan, but other than that, stick with the cheap-o ones and put up a 135' center fed Zepp and feed it with open wire...actually a 102 foot  center feed one works just as well if you dont have the room for full size.

73, Tim K8WBL
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« Reply #17 on: June 14, 2009, 10:42:53 AM »

I guess I'll chime in here about my experience with a commercial vertical. I had a Hustler 5-BTV. Even though it was extremely narrow on 75M with the resonator, it was the bees knees on 40M. I made my initial AM contacts with it on 40M. Also pounded tons of brass on 40 & 15. 75M being the exception, I was happy with it. I guess that is all that matters.
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Steve - WB3HUZ
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« Reply #18 on: June 14, 2009, 08:34:44 PM »

Just something to think about.

Take any reports of how good antenna X is when the guy giving the report says something like "I made a ton of contacts on CW." This doesn't mean the antenna is going to be worth beans for AM use. I figure CW easily has a 15-20 dB advantage over AM. This means you could have an antenna that is 20 dB down from someone running an average dipole when on AM. In other words, you'd be piss weak.

Think about it.
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« Reply #19 on: June 14, 2009, 09:11:02 PM »

Steve said:
Quote
Take any reports of how good antenna X is when the guy giving the report says something like "I made a ton of contacts on CW." This doesn't mean the antenna is going to be worth beans for AM use. I figure CW easily has a 15-20 dB advantage over AM. This means you could have an antenna that is 20 dB down from someone running an average dipole when on AM. In other words, you'd be piss weak.

I thought about it and I have come to the conclusion it worked FBOM on 40M at 7.290Mhz and 7.295 Mhz using my Heathkit Apache. It worked quite well on 10M AM. Enough that Ozona Bob heard me and gave me a dissertation on the Hammarlund HQ-100 I was using (I guess for about 40 min).  Wink
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Steve - WB3HUZ
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« Reply #20 on: June 14, 2009, 09:23:06 PM »

LOL. Don't think too hard OM. Mine was a general comment, not directed at you.

A wet noodle will make contacts on 10 meters when its open. I see this kind of anecdotal stuff all the time, like I worked 20 countries in one weekend, etc. Sure, when the high bands are hoping, that's nothing. Bottom line, verts with a few radials are not as good as verts with many radial or a modestly high dipole on the higher bands. More to the point, they suck. There just no getting around this reality.
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« Reply #21 on: June 14, 2009, 09:38:37 PM »

Yes, ham anecdotal antenna stories - the tales are endless... the hard facts are usually non-existent.   The only way to know what's going on is an A/B comparison against a reference dipole at the same height, or in the case of vertical polarization, a single vertical with at least 60 radials - all far removed to prevent mutual coupling.

We must remember how precious a db is. In an ssb pile-up, the guy with just a 1-2 db advantage will come out on top. A couple db can make the difference between hearing someone above the noise or not.

It really stands out when comparing a simple mobile whip on a car to a reference dipole.  I once parked my Blazer (with a HB 75M Bugcatcher) out in the field and compared it against the full-size dipole at 60'.  There was consistently only about -15db difference between the two antennas.  A poor Hamstick would be about -20db down from the dipole. This is for local stuff in the late afternoon, which is pretty good considering the vertical polarization of the whip.

So, to put it in perspective, if a lossy antenna (poor match, no radials, lossy traps, laying on the ground, etc) is down 15-20db due to problems, it's no better than a mobile whip on a car with no radials. Now THAT'S something to think about.... Grin

Even a full-size 3 element Yagi is only 4-5 db better than a simple dipole at the same height. How easy is it to burn up that precious 4-5db in a poor match, interaction with other antennas, house obstructions, bad connections, traps, etc?

Heck, ya gotta TRIPLE your power just to get 4.5db.

Everything has to be working correctly in unison to create a good antenna system. Match, height, good conductors, free of obstructions, flat, straight and tuned well.  Not an easy task.  Conditions are the biggest variable and power has something to do with it as well as location -  but after that the huge spectrum from totally PW to rock crushing strapping is due to guys doing antenna things well or not so well.

T
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« Reply #22 on: June 14, 2009, 09:51:26 PM »

I enjoy reading thru the old mags and its amazing what hams and manufacturers would claim for antenna performance in the days before computer analysis.

It got so ridiculous that QST banned any gain specs from ads for many decades. Of course the other rags just kept at it with 73 being the most laughable followed closely by CQ and also their CB monthly.

Carl
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Steve - WB3HUZ
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« Reply #23 on: June 14, 2009, 09:52:57 PM »

Here's a comparison of a vertical (with 60 radials) and a dipole at 40 feet on 40 meters over average ground. The red plot is the vertical and the dashed plot the dipole. You tell me which one is better.


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W3SLK
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« Reply #24 on: June 14, 2009, 10:48:34 PM »

Tom said:
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Yes, ham anecdotal antenna stories - the tales are endless... the hard facts are usually non-existent.   The only way to know what's going on is an A/B comparison against a reference dipole at the same height, or in the case of vertical polarization, a single vertical with at least 60 radials - all far removed to prevent mutual coupling.

Hah, hah! I remember a friend of mine loading into a light bulb on 11M with his DX-100. You should have heard the comments about that one on Ch. 19 Grin

Steve, not taking it full force but an observation that the aerial did work well on CW as well as AM. They were some nice days operating on 40M from about 11Am until roughly 3PM. Lots of OT's then.
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Mike(y)/W3SLK
Invisible airwaves crackle with life, bright antenna bristle with the energy. Emotional feedback, on timeless wavelength, bearing a gift beyond lights, almost free.... Spirit of Radio/Rush
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