The AM Forum

...hi from tim...i'm planning on putting more radials out from my  1/4 wave 40 metre vertical. the radiating element is a t.v. tower, insulated above ground...these will be the typical 1/4 length, but my question is one of placement...
...considering that the radials are all tied together, and in parallel, does it matter (much), that they physically are "bunched" together?....
...i know it would be best, to run them out from the antenna, equal spacing from each other, etc., in a circle. but this is the real world....i will do my best, to space them, and "fan" them out, but consider this....what if a guy used a multi-conductor cable, say 8-10 wires in a plastic jacket, 1/4 wave length long, and only terminated at the ground/radial feed point?...would this be of any use, or would the closeness of the wires only see one wire, instead of 10?...there will be some areas, where i will have to bend the radials, but they will be cut to about 32feet...
...any input would be great...

..tim...

..sk..

Think of the radial system as a shield, to isolate the radiating antenna from the lossy earth.  It also serves to provide the missing part of the antenna, if the antenna is less than a half wavelength long.

So you want to cover all the ground in the vicinity of the base of the vertical.  If the radials are bunched together, with large gaps elsewhere, the missing antenna length may be taken care of, so that the antenna can be tuned to resonance, but the "hole" in the shield will still be there, to use up precious rf energy to keep the earthworms warm.

The 'holes' will also cause some directivity variations in what would otherwise be a 'perfect' circle.   Your car's FM radio demonstrates this effect well, depending on where on the vehicle the antenna is mounted, frequencies in use relative to the car's metal (ground field) being less than, equal to or more than 1/4 wavelength, the direction your traveling relative to the transmitters, etc.

You may desire directivity and thus lay many of your radials in a preferred direction, but as Don says, you'll heat the ground in the other directions and/ or direct a a lot of the signal straight up as well as affect the inpedance of the antenna. 

The purpose of a radial system is to isolate ground losses from the antenna system, and to improve radiation efficiency.   A lopsided  ground system will be lossy (to ground) in the areas not covered by radials.   The more radials the better (up to a point).   Radials should be spread out evenly beneath the feed point.    A "bunched-up cable" would function as a single, but fat radial. 

An absolute minimum of four radials is required, spaced at 90 degrees, but more is better.  Broadcast towers  typically run 120 radials or more.   For a 14AVQ I ran years ago, I had 8 radials per band, except for 10M where I had 12.  The longer  radials for the lower frequencies aid the efficiency for the higher bands. This was effectively 34 radials on 10,  22 on 15, 14 on 20 and 8 on 40.   The antenna was roof mounted on a flat roof, up 35 feet.  It put out like a bomb.

Limiting radials to certain directions is a poor way to achieve directivity.  It only amounts to a dB or two at best, and even in the preferred directions the signal drops when the radial field is not complete, because some of the transmitter power is lost heating up the ground.  Less I^2 R(rad) in the vertical section means less radiation in any direction.

I put in 120 quarter-wave radials under my 160m vertical because I had the time, space and wire, but adding more radials is always a case of diminishing returns. 30 radials is a good compromise between cost, labour and efficiency.  There is very little difference in performance between 60 and 120 radials, so my 120 radials, and broadcast ground systems are overkill.  I suppose they keep the ground system efficient for several more years after the copper begins to corrode away in certain soils.

Elevated radials are affected by resonant length, but radials lying on the ground or buried become non-resonant, so the longer the better on any band, but again you reach diminishing returns.  The only disadvantage to using radials longer than 1/4 to 1/2λ is wasted copper.

It doesn't matter whether the radials are bare wire or insulated.  Insulation will protect the metal from ground corrosion, but has no effect electrically.  Ideally, the radials should lie on top of the ground, since burying them introduces a layer of lossy earth between the radiating antenna and the ground plane - the very thing the ground plane is supposed to eliminate.  But burying them  a few inches below the surface causes negligible losses and protects the wire from surface traffic.  I recall reading in an ARRL antenna book from the late 30's, recommending burying the  radials a couple of feet in the ground.  That would have required a ridiculous amount of work and would have resulted in ground losses.  I don't know if that was a misprint or if somebody really thought radials were supposed to be buried that deep for amateur frequencies. 

That completely depends on the install, Don.

I had a 1/4 wave vertical, one of the "dropping radial" no tuning method quarter waves from the 70s, called a starduster, mounted on top of an 8 element horizontal 10 meter beam.

I could point the beam at Los Angeles from San Diego, and had NO problems on the ground plane, making contacts in LA.

Point the beam at a rt angle to LA, NOTHING.

While I agree that buried radials, it makes little difference that we can measure... If you are doing it on a raised installation, putting a couple radials in a specified direction (or more to the point, away from a desired direction) can make a diff.

I have a friend using a ground plane, and a V Beam.  We ground both sides of the V beam and work the vertical against it on 10 and 15.  On 10, he is over an S Unit stronger in the "V Beam direction"....  15 meters is less, as can be expected.

Buried radials, I'd be willing to agree 100 percent with Don's statement.

--Shane

I found that using #22 0r #24 insulated stranded wire was the best for laying it down at the end of the mowing season and by the time late Spring arrives they will almost disappear into the grass. Use "SOD STAPLES" to tie it down every few feet to keep it from being a tripping factor.

I have had the worst luck with any type of bare solid wire of any gauge or larger stranded insulated wire. Almost always get caught up in the lawn tractor or DR Trimmer. I waste more time un-tangling the mess. Every Fall got to lay more new radials.........but using the above mentioned wire only now.

Don's response is a good one to follow. He is heard almost everywhere.

It looks like your installation is on an established lawn.

Fred

Your #22 or #24, was that bell wire, or better quality hookup wire?  Is it Available in large rolls, say 500 ft. at Loews/Depot?
Sounds good. Knew a ham that used sod staples on his RG8 too.  Right in the grass and it grew over just like yours.

I would venture to say that is true if the whole thing is  raised at least a wavelength or two above ground, as for example a 2m or even a CB ground plane.  As the ground plane approaches earth it becomes more and more like a buried radial system, and the  less effect the physical radial pattern has on the radiation pattern.  The low-band "elevated" radial systems with a  counterpoise raised a few feet above the ground will act pretty much like a buried system, although not quite as many radials will be required.

Think of two extremes. (1) a 2m ground plane vertical, 50 ft. in the air.  Only 3 or 4 radials are needed to make a completely effective ground plane. (2) the standard AM broadcast tower, with 120 1/4λ radials.  At several wavelengths above ground, not much is needed to shield the vertical radiator from earth.  The ground plane serves primarily to complete the resonant circuit of the quarter wave vertical radiator.  The closer you move the ground plane to the ground, the more radials will be needed to completely shield the vertical from the earth, until the radial system is sitting right on top of the ground in which case the maximum amount of shielding is needed.

I wonder how effective the "ground plane" was on that AM broadcast station in Los Angeles that had the old fashioned multi-wire inverted L mounted on top of the Odd Fellows building, and depended on the steel skeleton of the building for a ground system.  They recently moved the station because the new owners of the building raised the rent to ridiculous heights, the last station in the US known to use that kind of antenna.  I suspect it fell way short of FCC specifications, but they were allowed to keep on using it because of a "grandfather clause".

I've been reading the posts on this thread with great interest. IMHO, the most illuminating and solid is Don's, with one exception--quarter-wave radials. That length doesn't quite cut it from the standpoint of max efficiency.

I'm assuming many of you are not intimately acquainted with the Brown,Lewis & Epstein experiment performed in 1936, which became the reference for the standard AM BC radial installation. Their experiment at 3.0 MHz showed that beyond a radial distance of 0.4 wavelength from the vertical radiator, the displacement currents reaching ground become insignificantly small, but out to 0.4 wavelength the currents are significant to the total efficiency of the ground system. Thus, any length less than 0.4 wl increases the ground loss, while any length greater than 0.4 wl has passed the dimimishing returns point.

It must be remembered, as Don said, radials either in ground or lying on the ground are non-resonant, so the quarter-wave length is irrelevant, and that length does not contribute to the maximum efficiency available.

Now to the number of radials versus efficiency. To establish a reference point let's use that which is standard in the AM BC community, which is that the theoretical field strength at one mile with 1000w radiated by a quarter-wavelength vertical is 194.5 millivolts/meter. This, of course, assumes perfect ground. I'm going to include BL&E's graph showing the field strengths obtained with various number of radials, each 0.417 wavelength. But below I'll show the values of the field strengths appearing on the graph when radiated from a quarter-wavelength vertical.

No. of Radials       Field Strength      Relative Voltage       Loss in dB
     113                   192 mv/m              0.9846                  0.13
       60                   185                      0.9487                  0.46
       30                   174                      0.8923                  0.99
       15                   158                      0.8103                  1.83
         2                   126                      0.6462                  3.79

The relative voltages are referenced to 1.0 as the theoretical reference (no ground loss), and the loss in dB is referenced to 0.0 dB with respect to the theoretical.

The radials used in the BL&E experiment were No.8 copper, buried at six inches. You are probably wondering the reason for the unusual number 133. Well, after Lewis and Epstein had plowed in 100 radials they still had some wire left over. So the asked Brown what they should do with the remaining wire. He said "Plow it in." So the remaining wire amounted to thirteen more radials.

Don's statement that the radials provide a shield between the vertical and the ground. He is correct, but a slightly different way of considering the radial system is that of a mirror, such that the nearly perfect radial system creates a mirror image of the actual vertical radiator, thus supplying the other half of the above-ground radiator. Consequently, when the ray reflected from the ground joins the ray coming directly from the radiator we obtain a gain of 3 dB compared to a half-wave vertical in space.

On the ground plane antenna, invented by George Brown (of BL&E), his experiments showed that two radials were all that's needed. But the RCA marketing people said it would sell better if it looked more uniform, so the result became four quarter-wave radials. In the elevated ground radial system the radials are resonant at a quarter wavelength.

I may have said earlier that I performed all the engineering pertaining to the FCC requirements for a construction permit, as well as the final building of AM BC station WCEN, 500w on 1150 KHz. My Dad (W8YNG) and I plowed in 90 radials, four inches deep. (90 is all that's required by FCC) My Dad was a mechanical engineer and an expert at creative welding. He designed and built the plow we used to insert the radials. I drove the tractor while he managed the plow. Field strength measurements showed approximately 190 mv/m with 1000 w radiated. Our tower was a four-legged 300' self-supporting Blaw-Knox, leg spacing at ground level 16'. The station was sold a few years ago and the AM portion is gone, only the FM is left.

In the past I've had difficulty in keeping the columns in a table in alignment. In case my columns don't line up correctly when the table above is posted, perhaps someone can straighten them out.

Walt

On the QRZ site it's easy to edit, even after being posted. However, there is an error in my post immediately above that I've found no way to edit.

The error is in the text where I state 133 as the number of radials used in the BL&E experiment. The correct number is 113, as appears in the table.

Sorry about that,

Walt

Walt,
Look at the upper right hand corner of your posted message.  There should be the words  "quote" and "modify".  Click on "modify" and you can edit your post, just as on QRZ.com.  When you have made the change, click on the "save" button at the bottom.

I didn't intend to imply that quarter wave buried radials gives the maximum efficiency, but the difference in signal between 120 quarter wave radials and 120 0.4λ  radials would hardly be discernible on a practical receiver - again the phenomenon of diminishing returns.  With an elevated counterpoise, the radials take on a resonant characteristic, and when combined with a quarter wave vertical radiator, the whole thing becomes resonant, just like a dipole.

Another factor is the number of radials in the ground plane.  If you had only one small roll of wire, it would be better to use it to make a dozen or so shorter radials than to make only four 0.4λ radials.  But if you have enough wire and decide to lay out 60 or more radials, you will  get some advantage by extending each one out to 0.4λ. 

To bury mine, I made a homebrew plough that attached to a rear-tine Troy-Built garden tiller.  I removed the tilling tines and installed the plough as an attachment to the back of the machine, and made a reel to hold enough wire to make one radial, supported by a bracket between the handle bars of the tiller.  The blade would cut a slit in the soil, and feed the wire into the slit, all in one operation.  I made the blade bell shaped, with a pointed end on the sharpened cutting edge, and on the trailing edge I brazed a piece of steel brake line.  The wire fed down through the brake line, and I fixed it in place at the base of the tower, and as I went outwards with the tiller, it cut the slit and laid the wire all at the same time.  I got the idea by watching a phone lineman use a power tool they had for  laying buried telephone drop cable from the side of the road to the house.  I cut the pieces by hand to make the plough, using a hacksaw and some steel plate and angle iron, then took the pieces to a welding shop and told them how I wanted it put together.  It didn't work quite  right the first time, so I partially disassembled it with the hacksaw, made a modification, and took it back for them to weld together again.  I still have it round here somewhere.  It took me and an assistant about 3 days to lay out 16,000 ft. of #12 wire.

But if I had it to do over again, I would have a local farmer come and disc up the soil to a fine powder, then I would lay the radials on top of the ground, held in place with sod staples.  Within a few weeks, the wire would start to bury itself in the ground, and by the end of the following growing season, grass would have grown over the radials and the sod and thatch would completely cover the whole thing; it would be difficult to pull them up if I tried.

Walt,

One more edit in your response...

6th para, 2nd line, 9 words in from left "133" !

Regards,

Ralph, W3GL.

@ 1:05pm, 6/10...
Oops... I see by the time line, you hadn't gotten to the edit  yet...
Sorry, I misspoke.

Don, thanks for the assist on how to edit.  I looked and looked last night for the place to find an edit button, but I was so sleepy then that I totally overlooked the 'modify' button.

And Ralph, the error you spotted is the one I referred to earlier. Is there another one that I missed?

Now for everyone: I'll be pleased to email a copy of the entire BL&E IRE paper to anyone who'd like it, but please request it by email to me at walt@w2du.com. The paper is in the Proceedings of the IRE, Volume 25, No. 6, June 1937.

I've attached a coupla pics, one of my Dad assisting me, the other showing the ruts made where the radials went into the ground. This occurred in 1948.

Right again!  70 foot crank up tower, beam mounted about 1.5 feet above, vertical on top of a 12 foot section.

Interesting reading on the BC antenna.  I have to wonder what the level of radiation was for the people inside.. :)


--Shane

I have used an electric lawn edger to make ground slits for radials.   With mine you just raise the guard that is used for edging.

At first I tried using a power lawn edger.  But the slit would inevitably get clogged with clumps of loose dirt that made it impossible to push the wire down inside.  I gave up trying to use it with the first radial.  That's when I borrowed the heavy duty garden tiller and built the plough.

Since the building in L.A. has a metal skeleton, there might not have been much RF inside.  If there was, it was probably no worse than what we are exposed to when operating our stations.  I think for most of the years that station was on the air, they ran only 100 watts, and maybe upgraded to 1000 watts relatively recently.  http://gallery.bostonradio.org/2004-12/la/100-02598-lrg.html

I think the RF hazard from MW and HF has been blown way out of proportion.  I would tend to be careful around microwaves and UHF/VHF, but I think the worse thing you can get from lower frequencies is an rf burn when you come in direct contact with "hot" circuitry.

Frankly, given to-day's paranoid society that cards 65-year-olds when they buy beer and suspends kids from school for packing a plastic picnic knife in their lunch bag, it surprises me that by now someone hasn't successfully lobbied to outlaw amateur radio altogether, claiming that a transmitting station in a residential neighborhood poses a "radiation hazard" that will give everyone or everyone's kids (remember, do it for the "children") cancer.

Well, Don, I hadn't heard about 65-year olds getting carded, but going further on paranoia, I read in the news just last week about a kid farting in the school bus, and they suspended him for three days. Unbelievable!!

And about MF and HF being blown out of proportion wrt being a health hazard, what those proponents don't understand is at those frequencies people are VERY SHORT antennas. A piece of wire approaching a half-wavelength would of course have enough coupled voltage to cause some current flow on it, but a wire the length of people's heights would have insufficient voltage for any practical amount of current flow. Consequently, at those frequencies the voltage induced across the length of a human body would be so small that the current flow in the body would be infinitesimal.

Walt

It is true.  I have been carded more times since I retired than I ever was during all those years when I looked like I could possibly be too young to buy beer.

I always go out of my way to make a point to ask them if any damn fool couldn't tell that I'm old enough to buy beer, make as much a stink about it as possible, try to make the poor sap at the check-out feel as stupid as possible, and to try the patience of the people waiting in line behind me as much as I can.

Maybe if more people would make it an issue to refuse to cooperate with this sort of nonsense, society would regain some common sense.

As for the rf, you have a point.  If you stood on top of a loading coil so that your body was part of a resonant circuit, you might be at high rf potential, but the rf current flowing through your body would still be negligible.  And what current there was, would be confined to your skin area.

OET 65.

http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf

Excellent articles on radials in the last four issues of QEX.  Rudy Stevens, N6LF, built a test range and meticulously measured performance of various numbers, lengths and heights of radials.  By and large his measurements confirm NEC modeling and the wisdom expressed by Don and Walt above.  The articles are full of graphs.  He tries to let the numbers speak for themselves although he does draw a some conclusions.

A few things that struck me: 

Very few elevated radials match scores of on ground radials. They can even start low and slant up and still work gangbusters.  This, of course, can be very hard to do.

What I would call diminishing returns occurs way before 120 on ground radials. There is less than 1 dB improvement going from 30 to 60, for example, 1/4 wave vertical, 1/4 wave radials. 

The worse the antenna, the more the radials matter.  The curves for shortened antennas are much steeper than the curves for full sized antennas.

I don't have this series of four articles in electronic format and I don't know if the ARRL does either.  They were in the last four issues of QEX, 251,252,253,254.

Indeed. The point of diminishing returns will usually be far different for the amateur station than the broadcast station.




Shorter antennas have lower radiation resistance. Since efficiency is determined mainly by the ratio of radiation resistance and equivalent ground loss resistance, this makes sense.

While visiting with my uncle, We talked about this same subject about ground radials.  He worked as a broadcast engineer in the east all his life.  He said on many ocations they Trimmed off radials to stop signals from reaching NYC. He explained they did extensive testing and found that you could make a significant impact on the direction of the pattern with the length of the radials.

I have above ground radials. Mainly do to the lack of wire and space around my tower and vertical for 160.  I only use 4 radials about 2 feet above ground. My radials are short.. Only 30 to 40 ft long. Even with this in place, The tuning on the system changed and the performance was greatly improved. When I find a good deal on wire, I plan to add alot more and some full length radials. out. But for now, The 4 actualy work great!  When the Dog tears or knocks a couple down, I can see the tuning has changed. We have the worst soil being in Arizona so everything helps.

Clark

Consider tying your four radials to a common coil and resonating them.

Lots of interesting comments.  Radials are one of those topics hams will dissect and chew on to the end of time.  There have been a zillion studies done, each one examining radials from one point or another, and now all these articles based on modeling, so everyone can dig up something to prove his point.  When I was getting ready to set up my inverted L on 160, I spent some time gathering as much radial literature as I could find, and I read it all, looked at all the plots, and so on, and finally it all seemed to boil down to put as may down as you can, fitting them in your lot lines as best as possible, and operate.  Some will tell you to put a feedline common mode choke out at the feedpoint.  I found it unnecessary if you have enough radials, for the return current will divide up enough so the amount on the feedline shield is minimal.

The whole deal with RF exposure on any frequency that won't cause thermal heating is total B.S.   RF is non-ionizing radiation.  It cannot break dna bonds.  the RF exposure nonsense is just politics.  It has a point only if you want to walk out in front of a microwave dish emitting a high strength uwave field for troposcatter but you don't want ur eyeballs turned into hard boiled eggs.   Guys spend careers out at HF bc station tx sites, medium wave 50 kw sites, up on top of Sears, Hancock and Empire under millions of watts ERP of FM and TV with no problems.  

I used to think 120 radials was the gold standard, but that number is a FCC requirement and bc stations go along with it because it allows for an easier more expeditious (i.e. cheaper) proof of performance.

on high bands I'd tend to go with elevated radials; on 160 the problem is getting them elevated enough to work as elevated radials are supposed to.  hence, lots of radials on the ground (unfortunately, because they cost more).  

Clark, the ground conductivity in AZ is such that you will realize a significant transmit efficiency improvement with the addition of around 50 more radials.  you may not notice anything on rx, and listeners may not always give expected reports because of other variables such as propagation (keep in mind that even 50 kw stations on skywave sometimes come in lousy) but the money for the wire over time will be money well spent.  If you plan to be at ur QTH for several years, I'd invest in no. 14 solid insulated in 500 foot rolls.  too many radials means if a few get broken it's no big deal so don't think ur wasting money by putting down around 60.  Also no. 14 with the insulation on it is pretty strong and lays down easy.

73

rob / k5uj


photo below of my latest feedpoint tuner on 160:  

A crying shame those articles weren't published in QST, which has turned into a worthless POS and waste of trees.

One thing I've see in print a few times is that if you use a folded feed on a vertical (like half a folded dipole) you increase the impedance which reduces the losses  because the ratio of ground resistance to radiation resistance is reduced.
(eg Radio Handbook 19th ed p25.6)

I can't see how that could possibly be. Surely the the impedance that is stepped up IS  the real radiation resistance + ground losses and the ratio just stays the same?
                                                                                     Ian VK3KRI
 

No free lunch. The equivalent ground loss resistance is stepped up too.

Or you can think of the folded unipole system as a step-down impedance transformer between the feed line and the vertical.  The impedance of the vertical radiator is still the same, but the feedline sees 4X the base impedance.

This is a very nice thread indeed. I have had good commo with Walt.  And even though I am on a 1.1 acre lot, running .4 wavelength long radials would be a hassle to manage and the cost involved, even buying "surplus wire".
So, I would have to get as many as I can afford around the base of my shortened vert.
 
When I first moved here, I ran a long wire (600ft) beverage on the ground, on what I thought was not intruding on anyone. I figured, "who walks back here"?  By Spring time the wire was all rolled up in a pile on my property.

And Rick.....I wish wire was that easy to get. Although I have never looked in Lowes. I have to dig around the Internet for Surplus Wire to find something reasonable.

Fred

Think of the folded unipole as two vertical elements mounted side by side in close proximity, and connected together at the top.  The whole thing acts like a fat single vertical element, and at a quarter wavelength and lossless ground system, ideally the base impedance should be 36 ohms at resonance.  If you tie both elements together at the base and series feed them, the rf current will be equally divided between both elements so that each one runs half the total current. Now disconnect the elements from each other at the base, and feed only one of them, while connecting the other one directly to ground.  The driven element still carries half the total base current, but according to P=I^2 x R, to achieve the same power level at half the current, the load impedance at the driven element has to be four times the original base impedance, theoretically somewhere around 144 ohms.  But the  radiation resistance is still 36 ohms.  However, the tuning network may be able to work into a 144-ohm load with a little less loss than it would into a 36-ohm one.

As usual, Don is right on the money in his explanation of the folded unipole.

However, the following is a quote from my earlier post:

Now for everyone: I'll be pleased to email a copy of the entire BL&E IRE paper to anyone who'd like it, but please request it by email to me at walt@w2du.com. The paper is in the Proceedings of the IRE, Volume 25, No. 6, June 1937.

So far, only two have requested a copy of the BL&E paper that is the basis for the FCC requirement for radials that go with AM BC radiators, which has also become the worldwide standard. The paper delves deeply into both the theoretical basis for its statements and the reporting on many, many individual experiments which verify the theory.

In case my original offer was overlooked, for those interested my offer is still in effect.

I'm also pleased to tell you that the 'E' in BL&E was Jess Epstein, who was one of my engineering colleagues at the antenna lab of the RCA Laboratories, aka the David Sarnoff Research Center at Princeton, NJ.

Fred, I often hit the 'post' button before I said everything I wanted to say. My last post above is an example.

What I intended to say is to iterate Don's much earlier statement, that if the radials have to be short there should be lot of 'em, because the highest ground currents occur within the area nearest the vertical radiator.

Did you ever find out who rolled up your radials? Perhaps some squirrels?

Walt

Walt, there was a human involved rolling up the wire. I "ASSumed" that it was ok to run this wire on someone elses's property.

Rob, I like your tuner design, it gave me ideas for mine. Hoping to be remote controlled with some DC motors to tune capacitance and inductance. Slide up and down 160 and who knows where else.
I hope in the next month it will be up and running for the 160M. I have to get back into the radio mode. Tooo many things right now.

The #14 solid wire might not "disappear" as easily as my discovery with #24 stranded. I'm guessing you do not have to mow very much in your neck of the woods?

Fred

Hi Fred,  Thanks--the ceramic caps are overkill but they were what I had on hand.  I bought about 30 of them at a hamfest a few years ago for 1 or 2 dollars each.  There are four 500 pF and two 250 pF.  The 250s can be clipped in and out (the bluegreen ones).  That tuner can probably handle twice the power I'll give it at least, before the cap arcs.  If you build something similar just make sure the inverted L wire is at least 1/4 wave on the lowest part of 160 you want to operate otherwise you'll start loosing a lot of power in the inductor.   Mine is cut for the middle of the band so if I tune it down around 1840 the inductor dissipates 40 watts for 1200 w. going into the tuner (according to TLW modeling). 

I have to mow; I'm right in town (unfortunately) but what I do is raise the blade on the mower as high as it will go.  At the start of each mowing season I sharpen the blade.  If you do hit a wire with it, you want the blade to slice it, otherwise it will wrap it up.   Clipping a radial in two is a lot easier to repair.  If you have grass your wire will disappear into the ground surprisingly fast.  I even have 1/2 inch hard line sinking into the ground.  I can mow right over it, walk on it, run the mower over it--it's mostly invisible now. 

73

rob k5uj

..wow...lots of gud stuff..ok...how about a multi-band vertical?...
..in other words, would it work, it a guy was to take 5 different lengths of wire, say, for 160/75/40/30/20 (1/4 wave), attach them at the ground feed point, but have them "bunched" together?...so, you would have multiple lengths, in one wire run?...i would use many of these, kinda like 5 conductor rotor cable, having the longest fer 160, es the shortest fer 20..but understand, this would not be only one run of wire, but many, fanned-out from the vertical....

..tim..

...sk..

The ARRL manual and one of Orr's books both describe using rotor control wire as you talk about.

Both the 4 wire flat pack crap, as well as the rounded 8 conductor.

--Shane

Copper's down get it down soon, before it climbs back up.... ;)

73
Jack.

At least they rolled it up and didn't just leave a tangled mess, and piled it on your property instead of throwing it in the trash. 

The meth heads climbed my fence and stole two aluminum 10 meter verticals, and all my wire.  I turned on the station and could not hear anything. I went back there and found all the wire gone.  Lucky for us they really started cracking down on stealing wire. The sad thing is that what they stole they probably got $20 for.

Clark

Even more sad, one of the antennas you had stolen was retailing last week for almost 400 dollars!

20 to 1 profit to loss margin :(

--Shane

That antenna never worked right. Thats why it was down. The guy built the gamma match network using RG213 coax of 50ft. If you used anything else, It would not match.  The direct input was something like 20 ohms and the bandwidth was like 100KC. After talks with him I realized that he did not understand that the antenna should be tuned.. not the coax and the antenna.

Clark

I've used a lot of galvanized electric fence wire to augment the copper I have.  Lay it out in late fall, and staple it down using staples made of clothes hangers bent in a "U".  Don't use the Chinese wire, it's crap and is very poorly galvanized.   Oklahoma Steel and Wire which makes good stuff -- a sample of which I've had outdoors for two years now and no rust showing.  Come spring, when the grass starts growing, the wires dissapear and all is well.  Add some more again in the fall.

hey Rob,
Nothing wrong with overkill using ceramic caps. The RF voltages can get extremely high.
During my rich days I glawmed onto a couple of vac variables. I made contact with a machinist and incorporated a automobile door window motor to drive the vac variable in a my future tuner adventure. I hope I can finalize and connect by August.
The Galvinized aluminum is for very patient people. Very un-cooperating and easily chopped up in mowing season, if your don't staple it down every 4 feet.
UN-fortunately that great Shadio Rack Rotor wire is no longer available. That was a neat way to get a bunch of wire down in a short time.


And Don, I have had people tell me that laying a wire around their property is an invasion of their privacy. Like I can hear what is going on in their house by laying a wire near it. WOW oooohhhh they're comming to get me.........

fred

Senor Mop...

I, too, found the loss of Radio Shack wire.  I, too, found a replacement!

Sprinkler timer wire from Home Cheapo or Lowes!  I even found some that had 2 wires heavier gauge (for the motor of the rotor), and the signal wires where about 3 or 4 sizes smaller.

Was slightly more 'spensive, BUT a LOT better insulated.  I think it was only slightly more 'spensive, but not much.

You have to watch out, though, how many stations it's advertised for......  Each station gives you a pair of wires.....  Nuff said!

I'm using 50 feet of it now....  4 conductors used for the remote Tuna (an Icom clone), and 3 leads for the remote wattmeter. 


--Shane

Senor Mop...

I, too, found the loss of Radio Shack wire.  I, too, found a replacement!

Sprinkler timer wire from Home Cheapo or Lowes!  I even found some that had 2 wires heavier gauge (for the motor of the rotor), and the signal wires where about 3 or 4 sizes smaller.

Was slightly more 'spensive, BUT a LOT better insulated.  I think it was only slightly more 'spensive, but not much.

You have to watch out, though, how many stations it's advertised for......  Each station gives you a pair of wires.....  Nuff said!

I'm using 50 feet of it now....  4 conductors used for the remote Tuna (an Icom clone), and 3 leads for the remote wattmeter. 


--Shane

[/quote]

THANK YOU Shane. GUD info

Fred