CG-3000; http://www.arraysolutions.com/Products/cg_3000.htm

MFJ-974HB; http://www.mfjenterprises.com/Product.php?productid=MFJ-974HB

Hello,

I need to solve my problem on low bands; 160, 80 and 40m with one antenna.

These are my possible solutions (which is better according to you antenna/ tuner knowledgeable people).

The antenna will be used primary for contest.

1. Inverted L (15m + 25m) with radials, feeding with coaxial cable and CG-3000 in feedpoint
2. Dipole (2 x 20m), via 450 ohm open line and MFJ-974HB, on 160m the antenna will be used like T vertical and ground (@20m)
3. Dipole (2 x 40m), via 450 ohm open line and MFJ-974HB (@20m)
4. Inverted L (15m + 25m) with radials, via 450 ohm open line and MFJ-974HB

*What's the behave of solution 2. and 3. against halfwave dipole feed via 50ohm coax on 40 respective 80m with same height, @20m?

Thank You for all answers/ suggestions.

SM7VZX

Hi.

I have tried the combination 2 on the CQ WW DX Contest 2008 and i can say its horrible! I used the SGC SG-239 Tuner and 450 ohm Wireman Line.

On the CQ WW DX 2007 Contest I used an 2x40m Dipole with an angle about 120 degrees and also tuned by the SGC SG-239 Tuner direct at the feedpoint.

The Results are: CQ WW DX 2007 82 QSO's @ 160m
CQ WW DX 2008 40 QSO's @ 160m !

I think it's better to place the Tuner direct at the feedpoint of the Antenna.
So that's just my Contest Experiences. I hope I could help you.
Sorry for my bad English!

73 de DM5LK, Silvio

I like the inverted L configuration with radials. At home I use a ICOM AH4 tuner at the base of the antenna.
Antenna is 30M long. Works OK on 160, 80 and 40M. About 10M vertical section (in a tree) and 20M horizontal.
The horizontal section is bent because of the supports available.

On a DXpedition to KP2 we used a quarter wave vertical for 40M with a wire attached to the top. For 40M the wire was parallel to the vertical and connected to the base. For 80M the wire was horizontal forming an inverted L. No tuner but many radials.

On VP2M we used two inverted Ls (160 and 80M) with separate feed lines and 16 radials. No automatic tuner but used some tuning elements at the base of each antenna.

W3WH uses his flagpole antenna (~7.5M) as a quarter wave vertical for 30M and a wire attached to the top for the lower bands 40-160M. Definitely requires a tuner.

73

Larry K3VX

Hi,

in the DARC-Fielddays we use a 2x36m-Dipol fed with 450 Ohm open feeder tuned with a AT-502-Tuner by Hamware running 100 Watt and made more than 100 QSO on 160m every time.

I think thats another possibility for you but it's not as cheap as the other tuners. You can take a look at www.hamware.de.

73 Sven DL8HCO

No I don't have any information about losses in tuners. Are there specifictions available for the two tuners?

Generally, coils are the source of losses. Lee, K7NM, has written about "C-Match" with uses only capacitors to make a match.

This technique is very useful for antennas that are longer than 1/4 wavelength but shorter than 1/2 wavelength. Those antennas look inductive and so require 2 capacitors to make the match. Of course the match is for one band. An example is using a 1/4 wave 40M vertical on 30M. Using the formulas from K7NM the two caps are 675pF and 12.3nF. Use standard values of fixed caps to get close and for the 675pF a variable cap to adjust.

This method will NOT work to match a 1/4 wave 80M on 40M. OK for 17M/15M and 12M/10M combinations

73

Larry K3VX

Hi Samir

Glad to see your comprehensive approach to antenna design! It's going to be hard to predict the relative performance of your options exactly, because of the differences in directivity and knowledge about your ground conditions, however I would suggest that you take the following into account from my own experience with wire antennas over the past 50 years.

1. Your options 2 and 3 will perform like a dipole when operating on
their natural frequency. At the higher bands you will get some gain broadside to the antenna, which may be as high as 3dB depending upon the type of ground you have, with a corresponding reduction in response off the ends of the wire.

2. Bringing 450 ohm feeder into the shack (as opposed to coax) may
possibly cause some RF problems, especially with option 4, because the feeder will not be completely balanced.

3. Rather than making your wires to the exact dimensions, you may like
to make them a little longer or shorter (by 5 to 10%). This will reduce the feedline impedance and voltage when each wire is working as 1/2 wave and improve the efficiency of the tuner. The small difference when the antenna is working as a true dipole is unimportant.

My personal preference would be either option 1 (with the CG-3000 located some distance from the shack and using low loss coax feeder) or option 3 (if you can orient the dipole to favour your desired direction(s) and don't mind some loss off the ends)

Good luck & 73
Peter G3LET

I think the AT-502 is a much better solution, because it allows your 450 ohm feeder to be matched using a balanced tuner that is remote from the shack, whereas the CG-3000 can only tune a single wire and the MFJ-974HB must be installed in the shack. It is expensive, but I believe in Sweden you don't have to pay the 19% VAT!

The losses you find in all these tuners vary over the frequency range and
whether the antenna impedance is within the optimum range. I would
personally doubt if you would notice any difference in efficiency between any of them even though some fraction of a dB might be measured. Another consideration is that the CG-3000 and AT-502 will be installed in the open and sometimes in quite low temperatures, so it is possible that reliability may not be as good as the MFJ unit, which will stay in your shack I use a very similar home brew tuner myself, but having the feeder coming into the shack gives RF problems on some frequencies. It's a difficult decision!

73
Peter G3LET

Samir

I am using the ZeroFive antenna. I purchased it specifically for 40, 80, and 160...although I want to use it on higher bands when conditions improve.

I have it ground-mounted with 20 radials of 64 feet in length. Poor clay soil in central NC, on a suburban lot with trees all around and hoses in the near filed for these lower frequencies.

Had it for 45 days. My results are typical AND atypical.

. CG3000 is flawless true black box, I have the 12V couplers putting
DC voltage through the coax. Always tunes within 1 second with my TS570. I cannot tune on 160 - ZeroFive suggests some additional toploading wire, but I have not had a chance to do that yet (simple enough, but I am travelling for a project at work right now) Tunes great all across 80 and 40.
. DX results are superb: as a single vertical it has no directivity
and does not "hear well" (as expected), so I use long wires for listening.
But for the other station hearing me with my 100 watts, I am fabulously satisfied. See the attached XLS for my log. It rocks WAY better than my CUshcraft MA8040V and my low dipoles cannot compare!

I have some details on eham.net also. Hope this helps, Samir. Customer service fantastic also.

http://www.eham.net/reviews/review/74121

http://www.eham.net/reviews/review/74389

Mark Lunday
WD4ELG
wd4elg@arrl.net
http://wd4elg.net

See http://n4xm.myiglou.com.

73

Paul N4XM

Posted By K4SAV

When you try and make one antenna cover three bands (especially 160, 80, and 40), there will be some bands where it won't work very well. That is the situation with the choices you listed.

1. Inverted L (15m + 25m) with radials, feeding with coaxial cable and CG-3000 in feedpoint

With a good radial system this should work well on 160 meters. On 80 meters it is a poor performer. An 80 meter inverted L, an 80 meter vertical, or an 80 meter dipole will beat it. On some frequencies on 80 the impedance is very high and the tuner may have trouble matching it. On 40 meters it will work well in a direction perpendicular to the top wire. In-line with the top wire, it will have deep nulls. Note: Why can you only get the top wire up to 15 meters and you can get a dipole up to 20 meters?

2. Dipole (2 x 20m), via 450 ohm open line and MFJ-974HB, on 160m the antenna will be used like T vertical and ground

This should work well on 80 meters. On 40 meters it will work well perpendicular to the wire (more gain than a dipole) but the lobe width will be narrow (about 59 degrees). There will be large nulls in a direction in-line with the wire (much deeper than a 40 meter dipole). This antenna should work very well as a T on 160 if you have a good radial system. It should be better than the inverted L you listed in choice #1 due to the increased height. On 160 you will need a matching network at the base of the antenna. Feeding it with ladderline from a tuner in the shack will be a poor choice. Instead of the matching network, you might be able to use a homemade current mode balun at the base of the T. For best match it would need to be close to 16 to 1. This will be a difficult balun to build, but maybe it can be made to work for a single band and low power. You will also need about a 500 pf cap in series with the antenna to tune out the reactance of the antenna. Rather t han use ladder line to feed this, I would add another transmission line for 160. That can be a coax line. Then you will only need the 500 pf cap and no balun.

3. Dipole (2 x 40m), via 450 ohm open line and MFJ-974HB

This should be a fairly good antenna on 160, but for DX it wont be as good as the inverted L in choice #1 (most of the time) , or as good as the T antenna in choice #2. For 160 DX it would work better if you fed it as a T against a good radial system. On 80 meters perpendicular to the wire it will work very well, but the lobe width will be narrow (about 54 degrees). On 80, in-line with the wire it will have very deep nulls. On 40 meters it will have a butterfly pattern. Perpendicular to the wire it will have very deep nulls, maybe as much as 30 to 40 dB. (That's the same direction where it works best on 80 meters.) The lobes will have good gain, but because of the pattern, I would rather have a dipole at the same height.

4. Inverted L (15m + 25m) with radials, via 450 ohm open line and MFJ-974HB

I would not recommend feeding an inverted L with ladder line for multiple bands. The ladder line will radiate due the feeding an unbalanced antenna with a balanced line. You may have RFI problems both on transmit and receive, and the signal radiated by the transmission line will be mostly dissipated in the dirt contributing to inefficiency. It's also difficult to physically implement because the ladder line can't be placed on the ground. You could feed an inverted L with ladder line if you provided a current mode balun at the base of the antenna. This could work OK for a single band (although it's not easy), but over several bands the impedance of the antenna may cause the balun to become inefficient (depending on the exact antenna length).

My suggestion for 80 and 160 would be a modified version of choice #2. Feed it with coax as a dipole on 80 meters. Add a switch to change it to a T for 160. In this case the series cap will need to be about 400 pf. 40 is a problem. I would put up a separate dipole for 40 if you need to go in more than 2 directions, or add a 40 meter element and make a fan for 80/40 and then feed that as a T on 160. If you do that the series cap for 160 will need to be about 300 pf. The value may vary some depending on how much the wires slope.

Jerry, K4SAV

Hi Samir,

Have a look at the Cebik website and search for the article.

http://www.cebik.com/

You can register and search the archives.

The title is "If I only had one wire"

It's about a double zepp fed with 450 ohm ladder line.

For 160/80/40 it would be 176 feet fed in the middle. I used one for 40/20/10 this summer and it was outstanding. Use a tuner, of course.

I now have one up for 160 and it loads great. I have not had time to evaluate it on 160 as it just went up yesterday, but the only problem may be that it will not be a quarter wavelength of the ground so who knows what the angle of elevation will be. I think you'll find that it will be very effective on 75 for sure. I had two up here at right angles and switched between them and on 20 the VKs swore I was using a monobander.

Good luck,

Jim
W3BH

Just for information:
I use a Icom AH-4, 122 feet of wire. This antenna tunes 160 Meter through 6 Meters. The antenna tuner will keep the SWR 1:1 on all bands. I have been
Very happy with it. The only problem is power is limited to 100 watts.

I have also ran open wire to a 40 meter dipole and loaded it on 160 - 10 M.

Good luck on your decision

73;s W9RMA

Posted By NG0K

I cover 20, 40, 80 with three elements fed with one coax. It's a 5m vertical wire for 20 that is supported by a 10m alum mast for 40 and that supports the vertical section of a 20m inverted-L for 80.

Just like a parallel dipole only its fed against the ground radial system. I'm thinking that would work for 40, 80, 160 and you could tune it in the shack instead.

How about a trapped antenna like the Minooka special.

73, Doug NG0K

Hi Samir,

Please look up details on the Hi-Q-5 and -6 RT TAD, Tune-A-Dipole antennas.

With CapHats and long whips it will give you the best possible performance in a Remotely TUNABLE HF antenna.

73, Charlie

1. Assuming 15m vertical & 25m horizontal
Antenna will be omnidirectional on 160 & 80, within a couple of db. On 40m you can expect +4dbi performance broadside to the top wire, -6dbi in the direction of the top wire. Polarisation will be predominantly vertical on 160 & 80, mixed on 40. Vertical angle for best radiation is about 30degrees on 160m (good for DX). On other bands the presence of the relatively long top section increases high-angle radiation substantially (good for EU). On 160m, feed impedance will be very low, capacitative. On 80m, feed impedance will be very high, very inductive - I doubt the small remote ATU will handle it on these two bands. On 40m, feed impedance will be moderate and inductive.

2. On 80m & 40m radiation is horizontally polarised, omnidirectional and at predominantly high angle. At very low angles (<10degrees) signals off the end of the antenna are severely attenuated (>30db) but broadside performance is only -1dbi. On 40m, feed impedance is extremely high, slightly capacitative. On 160m (Tee configuration) radiation is predominantly vertically polarised and omnidirectional, with 1.6db gain over isotropic at 25degrees elevation. High angle radiation is heavily suppressed (good for DX). However, feed impedance is extremely low (<3ohms) and very capacitative. A loading coil might be required before ATU could handle and bandwidth is likely to be very narrow.

3. Horizontal polarisation and predominantly high-angle radiation on all three bands. For 160m and 80m, performs about the same as for 80m and 40m in 2. above. On 40m (at low angles only) this antenna becomes end-fire ...
radiation broadside-on to the wire is suppressed (>30db), radiation at 30degrees to the line of the wire (four lobes) is enhanced. There is thus a substantial difference in directionality between local and DX contacts.

4. Exactly the same as 1. but with a better chance of the ATU being able to match the antenna.

None of the antennas is sufficiently close to 50ohms to be fed directly with coax. It is not a good idea to bring any feeder, other than coax, into the shack. This applies particularly with antenna 4., where the feeder is not being used in a balanced configuration.

If you feel like experimenting with your own antenna designs, I recommend EZNEC software, by W7EL. It can be downloaded via the Internet at very reasonable cost.

Hope this helps

Vy 73

Steve G3UFY

My best approach to your problem would be option 3 but cut the antenna 10% less on 160m so that on 160m you don't have a very high impedance at the feed point which might give you a problem tuning the ATU.
Shortening it by 10% is unimportant to antenna performance.

Also
make sure when you are feeding the antenna with 450 Ohm twin feeder you cut the feeder NOT to a 1/4 wave or 1/2 on any freq as this will act as a transformer and again present very high impedances which the ATU may or may not cope with.

Since you will be running no more than
300W SSB 150W CW (MFJ-974 ATU rating) bringing open wire feeder into the shack and into the ATU is not an issue either, providing it's not running around the shack but is going through the wall and straight down into the MFJ.

The advantages with option 3 is that it's a balanced system and there will be some gain on the higher frequencies.
It is also more efficient than the other options, less loss on the feeder run compared to coax.
Also less expensive as putting out an effective grounding system for your "L" antennas will probably cost many times more than 2 x 40m.

Disadvantages,
well, with the vertical section of the other options you will have vertical radiation which may be to your advantage if you are aiming to chase DX. DX is of course also possible with the 2 x40m.

I have
put up many antennas like the one I have just described on many-a-contest and at home and have never had any problems with good DX on 40m & 80m but less on 160m.

Good luck and let us know what you decided to do.

Regrads,

Berni
G0IDA

Hi
I have a similar problem to you in trying to find a good multiband antenna for 160/80/40. I don't have any solution yet but have received some interesting suggestions about 15m high 'T' verticals with switchable top sections which promise good DX on all these bands when used with plenty of radials.

I have used both ATUs you suggest. The MFJ-974 has worked well for me and does an excellent job when feeding a doublet/dipole with 450 ohm ladderline.
However, if you buy this unit I suggest you open it up and check- mine had several problems like loose variable capacitor vanes and untightened switch connections (which were easily fixed). The CG-3000 I have used exactly as your Ant 1- it's been outside for nearly two years and has lasted well. It has the big advantage of being an autotuner- very good when doing quick QSYs or band changes in contests. When I used the CG-3000 next to the rig it appeared to generate a small amount RF interference on 20/15/10- but I never tracked down the reason for this but it was the reason I moved it outside the shack eventually.

In my limited experience I have found that my inverted L configuration much outperforms my horizontal doublet on 80m (2x14m), but is only marginally better on 40m. Both antennas are poor on 160m.

Good luck- I suspect you will experiment with several options before you find what's right and that's all part of the fun...

73 Dave G3ZQH

Hi !

It's really impossible for me to say which will be best as I have no idea of your location and it's surroundings !
The Inverted L and the CG3000 will give you the most flexible and convenient solution and is easier to maintain than the dipole solution.

It's always best to have the ATU at the antenna, not in the radio shack, so the CG3000 wins there again, however it is impossible for me to advise you on the decision.

Good luck with whichever you decide to try.

Mike.
F5VKM / M0AWS
http://www.f5vkm.com

Posted By NO9E

I have a dipole for 80m at 20m fed by ladderline, a trapped dipole for 160-30m at 15m fed by coax, full size wire verticals on 40 on 80, and inv L for 160m. The last one is about 25m vertical and 20m horizontal and the 80 and 160m verticals use 9 elevated radials. The ground is clay and may be poor.

Usually the best antenna by far on 80-30m is the 80 ladderline dipole. It was also better than a smaller inv L on 160m but the current inv L beats it by about 3 db; the trapped dipole is some 10 db down. The 80m vertical is better than the ladderline dipole for DX in directions where the dipole has nulls.

The trapped dipole does not require tuning on 40 or 30m. It is also the quietest rx antenna.

Summarizing, all antennas except the 40m vertical are useful. but the 80m dipole fed by the ladderline is the single best antenna. Also the cheapest and no maintenance in 12 years. I consider another such dipole perpendicular to the current one.

The tuner for the dipole fed by ladderline is TenTec 238. Handles 1.5KW without a problem and has flat tuning compared to T tuners.

Right now I think I will drop all possibilities and put simple Inverted Vee (on SPIDERBEAM 18m pole) with (http://www.unadilla.com/traps.htm) traps for 80 and 40m.

Will be using it in CQWW SSB 2009 contest.

TNX & CU
Samir