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Hi there. I am considering different antenna types in anticipation of setting up a QDX?Transceiver.
Right now, I use a??that is resonant on 80, 40, 30, and 20 meter bands. I have a magnetic loop, but that does not cover 80 meter band, so its use would be limited to 40, 30, and 20 meter bands when using the QDX?Transceiver.
I am considering a QRP tuner and an open wire 600 ¦¸ ladder line antenna that covers 80 to 10 meters. The tuner previously mentioned in this group that I am considering is the following:?. It supports low power operation and it allows coaxial or ladder line wire to be used on the output. For the QXD to tuner connectivity, I am considering a short length of BNC male to S0-239 male cable. I have not sourced this part. I am considering SO-239 connectors on the tuner because those connectors are more universal.
The potential system would be QDX -> Tuner -> ladder line -> dipole.
My thinking with a ladder line is the capability to tune the bands with a tuner and not have to worry as much about unclipping sections of my?. I can use the segmented dipole because it resonates on each band, but it requires taking down the antenna to switch bands. That is not too much of a hassle, but it increases the complexity of radio operation.?
I am wondering if anyone has experiences that can be shared in working with open-wire 600 ¦¸ ladder line dipoles. I know about the pros and cons of operating near metal objects or working with sharp bends in the wire. None of which I am anticipating being near my operation. My operation would be portable with a pushup pole in a field or near trees (support). My priority is less complexity.
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You might check online for advice about multi-band, ladder-line DOUBLETS. Here¡¯s a detailed look at them.
¡ªMike Perry, WA4MP
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On May 28, 2022, at 2:57 pm, Linus <linus.peter.sweers@...> wrote:
I am wondering if anyone has experiences that can be shared in working with open-wire 600 ¦¸ ladder line dipoles. I know about the pros and cons of operating near metal objects or working with sharp bends in the wire. None of which I am anticipating being near my operation. My operation would be portable with a pushup pole in a field or near trees (support). My priority is less complexity.
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This the open wire dipole that I had in mind.?
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On 28/05/2022 22:16, Linus wrote: This the open wire dipole that I had in mind. This can be homebrew at a fraction of these prices. Instructions-a-plenty online. Michael
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Hi Linus:
"My operation would be portable with a pushup pole in a field or near trees (support). My priority is less complexity."
I think you may have defined?what you already have as the best solution. You will be portable?with a push up pole and your priority is less complexity, so leave the tuner and the ladder line dipole and just pack the small segmented dipole. You can lower it and add or remove segments and push it right back up in a small amount of time and get consistent results without having to pack a tuner. Sometimes the simplest solution is also the least complex and easiest to manage in a portable situation.
Good luck ... Ron
On 28/05/2022 22:16, Linus wrote:
> This the open wire dipole that I had in mind.
>
This can be homebrew at a fraction of these prices.
Instructions-a-plenty online.
Michael
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All,
Good comments and opinions so far. Ron you reaffirmed my thoughts?
Any open ladder line users with performance details? I might put one in use in my base station and use the segmented dipole for portable use.?
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I have used 600? open wire feeders many times over the years but have settled on 450? because the feedline is less cumbersome?than 600? for field or portable use and results have been satisfactory. Having said that, installing 600? line at a fixed location such as home, the feedline doesn't get tangled up from constant installing and uninstalling. GL OM, 73, Greg W2BEE
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I use a 40m doublet fed with 300 ohm line, tunes anything from 40-10m with a BLT tuner (equivalent to the ZM-2). Works great if you can get the centre up at least 10m or so...
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41 m EFHW and a 1: 41 transformer plus a chocke at 4 from the feedpoint and off you are on all bands. Tunes easily by folding back the far end and no tuners needed.
Martin DK3UW
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I have used an open wire doublet for years here. It works very well on all bands from 80 to 10 including warc. It is 110' end to end, fed in the middle with 4 inch open wire into the shack to an old Decca kw107 tuner. The wire is aluminum#17 electric fence wire from the farm store. The open wire is made from more of the same wire with 4 inch plastic spacers every couple feet.? I started with the antenna at 130' long but it didn't like 40 metres. 110' is much better. The materials are very inexpensive, both the wire and fence insulators were less than $30 at the local TSC farm store. It would be cumbersome to use as a portable antenna though. It is fairly stealthy at home with the aluminum wire.? I am impressed with the performance of it. It seems better than fan dipoles that I have used to try and get multi band operation.?
73 Don ve3ids
All,
Good comments and opinions so far. Ron you reaffirmed my thoughts?
Any open ladder line users with performance details? I might put one in use in my base station and use the segmented dipole for portable use.?
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I have also been using a classic Cebik doublet for 40-10 meters for years with good results. I use 300 ohm window line to a 1:1 balun to a remote antenna tuner. It's paired with a wire up to tree top vertical that I use for 160-40 with the remote tuner antenna switch selecting between them.
At a previous QTH I had tall trees and ran the doublet oriented vertically.
--
? 73
??? KD8CGH
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I did simulations on a 44 foot doublet recommended by Cebik (SK), good for 40M-10M.? Used EZNEC to generate a "last Z" file which I fed into SimSmith. This doublet has some advantages. I found, with simulations in SimSmith, that you could make the 44 foot doublet at 35 feet high? with 300 ohm ladder-line such as DX Engineering DXE-LL300-1C, 59 feet, 1 inch long fed with a 1:1 balun. My goal was to get VSWR low enough to be able to use the 3:1 capable tuner built into many modern rigs.? I succeeded in this for the 30M, 20M, 15M, and 10M bands. 40M needs an external tuner.? For QRP rigs, you would need an external tuner but no critical tuning. A simple L-network would do the job. See referenced article. Tune the electrical length of the ladderline by terminating it with a 2K resistor (not critical)? and look for a dip in VSWR at 4.273 MHz.?
30M: VSWR=2.5
20M: VSWR=1.5
15M: VSWR=2.2
10M: VSWR= 1.6
-Steve K1RF
------ Original Message ------
Sent: 5/29/2022 7:52:24 AM
Subject: Re: [QRPLabs] Antenna System Multi-band
I have also been using a classic Cebik doublet for 40-10 meters for years with good results. I use 300 ohm window line to a 1:1 balun to a remote antenna tuner. It's paired with a wire up to tree top vertical that I use for 160-40 with the remote tuner antenna switch selecting between them.
At a previous QTH I had tall trees and ran the doublet oriented vertically.
--
? 73
??? KD8CGH
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Take a look at a ZS6BKW antenna. Not difficult to build and resonates within several different ham bands. Mine works great (even though it's too low at 25') with a ZM-2.
There are some commercial versions out there.
The only discussion group that I am aware of is on Facebook -?
Here are some construction details,?
Tom?
W9KKQ
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This is a better description of the ZS6BKW
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On Sat, May 28, 2022 at 10:18 PM, Michael.2E0IHW wrote:
This can be homebrew at a fraction of these prices. Instructions-a-plenty online.
I'll buy two ;-)
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I modeled the ZS6BKW using NEC 4.2 using the specified antenna and line lengths, and assumed a 30 ft flattop height over average ground, which is probably attainable in many portable conditions.? Generic 450-ohm windowed line was also assumed. ? The 41 ft line length works reasonably well on 80/40/20/10m but SWR at the input end of the windowed line is approx. 20:1 in the middle of 75m. ?Reducing line length to 33 ft brings SWR under 2:1 at 3.8 MHz. ? On 15m, SWR is also near 20:1 at 21 MHz. but reducing line length to 31.5 ft brings SWR to less than 1.5:1.? ? On 30m, SWR is over 100:1 but can be brought down to less than 1.5:1 with 65 ft of line.? ? So ¨C if I were to use the ZS6BKW antenna, 30m would be discarded and I would cut the main line length to 31 ft instead of 41 ft.? Then, windowed line jumper sections of 1, 2, 4, and 6 ft. are made with sockets/plugs on the end.? Once the antenna is up in the air, make note of the lowest SWR at the transceiver by trying different line jumper sections.? It might take 15 minutes or so, but as long as the result is recorded on paper, switching in/out sections for band changes should be easy. ? 17m/12m modeling shows that SWR can be brought to under 1.5:1 with the line section jumpers.? ? The closer the input end of the windowed line is to 50+j0 ohms, then the SWR at the input end of 50-ohm coax section will be minimized with varying length.?? ? Given the hassle involved for true all band operation, I would lean more toward using an efficient ATU at the input end of the windowed line that can manage high SWR.? The windowed line can be trimmed in length to find a reasonable complex impedance within the range of the ATU. ?If efficiency and antenna field strength isn¡¯t of utmost concern, then consider the EFHW or OCFD.? ? Paul, W9AC ?
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Linus: for portable ops you will find 300 ohm (TV) line much easier to deal with and lighter. I use a 40-15m doublet fed with 300 ohm line and it tunes anything with a BLT tuner - all very lightweight.
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My son goes through cheap toothbrushes rather rapidly.? I used to save the handles (after a check in the microwave) to use as 4 inch spreaders.
Mark K9TR
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...the other cheap spreader material are inexpensive dollar store plastic hangers cut up to same lengths and then drilled to the right wire thickness.
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Mike Perry, WA4MP
Ronald Taylor
Don VE3IDS
Bob Benedict, KD8CGH
Paul Christensen
Mark K9TR