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You can
write your own review of the No counterpoise Antenna System.
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KD6FAB
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Rating: 5/5
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Mar 3, 2009 16:55
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Perfect Portable Antenna
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Time owned: more than 12 months
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I've been having a blast with this antenna design. After purchasing one of these from Jeff's Ebay store I became curious about
how well this simple design works. It's probably the easiest antenna to make (even easier than a half-wave dipole), so
after researching the antenna and speaking to several people about it's design I decided to make several myself to experiment with.
Jeff sells them made out of low voltage landscape wire (heavy duty lamp cord), I opted to make mine out of 300 OHM ladder line. Couldn't be simpler, take whatever length of twin lead you are going to use (half wavelength or so) and at the center (halfway from one end or 1/4 wave length)
cut one side of the twin lead and strip it away. You end up with twin lead for half the antenna length and a single conductor
for the other half. The single conductor becomes the radiator and the twin lead section becomes the antenna's feed line. For best results attach the feed point directly to an antenna tuner.
Some argue that this is an end fed zep, I believe it is more of a parallel OCF dipole with interesting properties that both Pete Mills and LB Cebic have modeled and wrote about:
The parallel feeder acts as an impedance transformer that keeps the feed impedance down, so it never gets above a few hundred ohms over a wide range of frequencies. Most rigs' internal auto tuners will have no problem tuning this design. A 50 footer will easily tune 40-6 meters. A 33 footer (for my jackite pole) easily tunes 30-6 meters. The most interesting property of this design however is the radiation pattern: For all frequencies that the antenna will load up on, the distributed current maximum stays at or near the center of the antenna where the twin lead stops and the single conductor continues. This keeps the antenna radiation pattern very favorable and similar to that of a resonant half wave dipole, except unlike a half wave dipole antenna being used as multi band antenna, this favorable radiation pattern and current distribution remains intact over the full range of frequencies tunable for the antenna! This means nice, low angle radiation with decent gain over a broad range of frequencies (using a tuner) without having to adjust the antenna length!
This for me has become the ultimate portable antenna. One length of wire, end fed and broad banded, incredibly easy to deploy just about anywhere. I typically operate portable with a FT857D, a small battery operated LDG auto-antenna tuner with this antenna (50') plugged into it. Tunes up 40-6M no problem and performs well. What more could I ask for?
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KI4PJY
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Rating: 5/5
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Jul 19, 2008 08:52
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Need Help
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Time owned: 0 to 3 months
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I purchased the antenna for 10-20 meters. It is exceptional quality better than I could build and he seller is quick to respond to questions. I am new to HF and have not yet made my first contact. I have a ICOM MKII and an LDZ 100 auto tuner. I have yet to be able to get the antenna to tune at either band. I have tried it with additional coax and directly to my tuner with the supplied pl259 connector. Tried it vertical and at a 45 degree angle 20 feet up. I am rating it great because I am sure I am doing something wrong. My tuner will not tune as the swr is in excess of 2.5. Does anyone have additional suggestions. I am a new ham with a General ticket itching to make my first contact. 73 to all.
Heyward
KI4PJY
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N2UGB
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Rating: 5/5
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Jul 18, 2008 15:03
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10-20 model WITH counterpoise
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Time owned: 6 to 12 months
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Because of space limitations, I use the 10-20 version of this antenna. It is outdoors but in a rather awkward configuration. Some sharp bends. On 20M I have no problem loading it through my QRP MFJ tuner. However, there was no way to get the SWR level down to an acceptable level on 17 meters. My Yeasu FT-817ND strongly objected.
So, I disregarded the no counterpoise required selling point and cut two of them. One for 17M and one for 20M. They are inside running along the room baseboard.
With their addition, I am now able to tune 17M without a problem. While 20M wasn't a problem, I decided to keep that counterpoise anyway.
I give it a 5 rating because it does what is supposed to do. It isn't advertised as equal to a good half-wave dipole. But it does the job for me. If this antenna were properly configured I, probably, wouldn't need the counterpoise.
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WA6MOW
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Rating: 4/5
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Jan 12, 2008 20:51
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It works well.
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Time owned: more than 12 months
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I use this antenna on camp trips in the Mojave desert. I sling shot it over the tallest Joshua tree in the area (maybe 15 ft. high) and kick back in my lounge chair. I use a tuner and an Icom 703 or my new FT-817nd. The last trip out in Oct 07 , using the 817 I worked lots of stations on 80, 40, 30 and 20 cw. What a kick. It works better than my ham sticks. It is light and travels nicely.
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VY1GP
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Rating: 5/5
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Jul 6, 2007 07:12
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Versatile, convenient
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Time owned: 0 to 3 months
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There is a lot of RFI in my neighbourhood. It affects the lower bands and I can't hear much over the background noise. This antenna helps solve the problem inexpensively.
When I want to get a couple of hours of clear signals, I jump in my van or car, drive 3 minutes to the edge of the subdivision with my antenna. In less than 5 minutes I set it up as a sloper, using a portable extending 30' fibreglass mast. I lean the mast against some small trees and drape the rest of the antenna over trees and bushes back to the radio on my dash. It works very well with a portable antenna tuner - manual or automatic. I checked it with a portable analyzer as well and there is excellent SWR with the manual tuner. It takes 2 or 3 minutes to take it down and roll up neatly for next time.
George VY1GP
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VR2UIX
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Rating: 5/5
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Apr 23, 2007 19:07
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Simple and good, should have one.
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Time owned: 0 to 3 months
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I have built the 25 foot long version with some cheap speaker wire (HK$1.00 per yard)for 20 to 10 meter operation. The construction was easy and simple, no special tools and technique required. It must be used with an ATU in order to make the transceiver feels happy and my MFJ 904 does this job very well.
This antenna works very well from my QTH. I just hang it on my window handle-bar with some nylon rope as insulator then drop it down vertically from my bedroom on 6 story height. I used it with my FT897D and 100 watts to QSO with an America Samoa station on 20 meter with both 59 signal report exchanged. The distance from Hong Kong to America Samoa is about 8,900km. Amazing.
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KC8TUA
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Rating: 2/5
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Mar 25, 2007 00:13
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RF in shack
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Time owned: 0 to 3 months
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I tried this in the shack and on my first floor apartment patio several times but got a lot of RF. I ran the antenna to a tree with fishing line and got less RF but would not load on 20m. on my Icom 746. Could not make any contacts I gave up. Very disapointed with my new GENERAL LIC. I have waited 30 years to get and no contacts. I ordered a MP1 From Gigaparts and got my first HF contact on 3/23/07. My radio is grounded with a 2ft. rod and a 2ft. strap. I will keep the no counterpoise antenna and play with it at at a later date but I would not buy it again.
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OE3SGU
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Rating: 5/5
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Oct 15, 2006 11:37
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Nifty - and it works
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Time owned: 0 to 3 months
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Bought one from Petes ebay shop and shipping was done very fast. The unit is good built and yes it really works, guess i take it with me to my next holiday. Of course its not a substitute to a "real" antenna like a dipole or a good vertical, but a very good and cheap compromise with overall performance.
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PETEMILLIS
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Rating: 5/5
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Jun 14, 2006 11:19
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So simple yet so good
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Time owned: 0 to 3 months
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Thia antenna really doesn't need a seperate counterpoise. This has nothing to do with defying the laws of physics. A basic understanding of antennas will tell you that the twin wire section is effectively a balanced feeder. This then meets the single wire, which can be seen as an unbalanced antenna.
Now what happens when an unbalnced antenna is fed with a balanced feeder? - The feeder radiates. The RF on the feeder balances the RF on the single wire section - result is current distribution resembling that of a dipole.
This works well, but you do need to understand that the radiating twin wire section will introduce RF into the shack if the antenna isn't properly fed. Properly feeding the antenna means using a balun and tuner (or a balanced tuner) and the balun should be outside or at the entry point of the shack (as with any end fed wire antenna).
Grounding the wire to the window frame is not a good idea - all you are doing is ditching the RF on the twin wire section to ground and so wrecking the entire way in which this antenna works.
If anybody wants to see EZNEC models of the antenna (both 25ft and 50ft ones) as well as comparisons with similar length single wires, then I have these available.
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KC5EJT
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Rating: 2/5
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Jun 7, 2006 07:47
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OK but needs a ground
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Time owned: 0 to 3 months
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I tried it without a counterpoise as the sellers recomends, but I had RF in the shack when running 250 watts. But I simply connect the dead end
of the feedline portion to the window frame (it's aluminum) where the antenna goes out of the house, and voila no rf in the shack.
Can't defy the laws of physics, it needs a counterpoise, though not much of one.
The science behind the need for a ground is here in W8JI's site:
http://tinyurl.com/lofgz
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