Category Archives: Antennas
As I try to continually improve my Station, I keep coming back to the antennas. I have a couple very nice Radios, but I am still not very competitive in Contests, especially DX contests. I have always used mainly wire antennas and generally if I can hear them, I can work them. Now I know the problem is that I can not hear enough of them!
I had an opportunity to work a Contest from a world-class Contest station (NR4M) recently. The contest was the ARRL International DX CW. I won’t go into the details of the antenna system there (you can search on NR4M), but let’s just say they have about 65 acres worth of antennas like I will probably never see anywhere else.
I had access to all kinds of antennas on all the HF Bands. One antenna group that really impressed me was on 80 meters. I heard all kinds of DX during the weekend and I even managed to work China on 80 meters. That will not be happening at my Home QTH any time soon. I was using two antennas at the time, in Diversity Mode on a K3. This was quite a new experience. The diversity did just enough to bring the China station’s signal out of the noise enough for me to work him.
So the lesson learned here is that if I really want to improve my station and get to the next level, I have to do something about the antennas. First project is going to be getting a yagi on the roof. I will always use wire antennas, and I will be trying to improve them as well. I recently installed a Beverage antenna for the first time. At a length of about 300′, it is not very long, but I am hoping it will improve my hearing ability on the Low Bands.
Of course another thing I could do is raise my Power to the KW level. I do not plan to do that, mainly due to the small lot I am on and the close proximity of my antennas to the Shack. I think going QRO would result in an RFI nightmare.
After a weekend-long CW contest at my Home, I jumped into my Ford F-150 to head out, and it was acting very strange. It seemed like the automatic transmission was dead or dying. I knew it was a little touchy going into 2nd gear at times, but it had been working just fine when I parked it for the weekend. I thought my week was ruined and I would have to call for a tow of my truck for an expensive transmission repair.
As I headed out of the driveway, shifting was still awkward. Then I noticed that as it changed gears, the dash display still said I was in 3rd gear. Once I saw that I knew something was fishy. So I went back to the house. I went through a couple power on-off cycles and things started to change. The dash display went nuts briefly, but then it started to come back to normal.
Seeing this change in behavior made me finally realize what had happened. I had parked the truck with its HF rig and screwdriver antenna right under one of my wire antennas, a ZS6BKW. The tip of the truck’s HF whip was directly under the antenna and only about 20 feet away. My guess is that there was RF coupling between the Home antenna and the wiring in the truck. As a result of the RF, some computer memory in the truck got corrupted. Eventually the vehicle must have loaded some historical or factory settings. After that, all was well again.
So now, when I park near the Home HF antennas, I remove the whip from the truck. I plan to do some more RFI mitigation soon, but for now this seems to have solved the problem.
Here we go again. Time for ARRL Sweepstakes CW (SSCW) 2014. Same plan as always – main objective is to get a personal high score. Secondary objective is to get that elusive “clean sweep” – all US and Canada Sections in one weekend. I have been within 1 or 2 sections the last several years, with Nebraska being the holdout last year. Never even heard it! Yes, really, NEBRASKA. Oh well..
I always like to try a new antenna or 2 for SS. This year I may need them as the forecast is for high winds nearly all weekend. Got 4 antennas and two radios for the hunt this year.
- 80m dipole, ladder line fed, usable on all other HF Bands as a doublet
- ZS6BKW oriented E-W
- ZS6BKW offset 45 degrees from antenna #2
- 6BTV Vertical on a pier over the Chesapeake Bay
The radios are an ICOM IC-7600 and an Elecraft K2
I have no idea how I will do in terms of score, but I know I will have fun. Hopefully one or two of the antennas will still be standing when Sunday night gets here.
I had an HT (Kenwood TH-F6A) connected to an antenna switch, connected to the two antennas. I tuned to a weak repeater. I found that I could hear it with the roof-mounted antenna, but not with the door-mounted antenna. I could switch the antennas between the 2 mounts with the same result, so it was the mount or the mount location making the difference.
When I opened the door with the antenna on it (moving the antenna and mount away from the chassis), I suddenly could copy the repeater with either antenna. I had the bottom of the door-mounted antenna about 4 inches below the roof line. moving it up about 2.5 inches made a huge difference in reception.
So if you are using one of the door-edge mounts, you may want to experiment with the placement.
Well I kept up the time-honored tradition of missing 1 or 2 Sections in the CW SS contest this year. Had about 575 QSOs (a personal best) and all but 2 Sections – MB and NNY. I never had trouble with a New York section before. I guess the monster storm Sandy may have been the reason, as they were all trying to get their lives back together and probably had little time for playing with radios.
I did not make any further adjustments of my ZS6BKW (ref: earlier posts on this subject). The SWR was well within usable range for the CW Band segments and I did not want to jeopardize that just before the Contest. Now that CWSS is over, I may get back to some final tweaking of this antenna to see if I can get 80m Phone in the 3:1 range needed by the IC-7600’s internal tuner.
I did try the 20m 4-element colinear antenna this year. I can’t say I was real impressed. I guess a fixed antenna with higher gain is not really what I want. Next year I may go to something rotatable. I did pickup a couple sections with the colinear that I could not get with my other wire antennas, but overall I am not sure it was worth the trouble.
Well, hurricane Sandy did no damage to my Chesapeake Bayside QTH. I am thankful for that and I wish a quick recovery to those that were ravaged by this nasty storm. The winds did leave one of my antennas needing attention. The winds pulled my anchor for the center of my ZS6BKW antenna out of the ground and it is now hanging in mid air. This should not be difficult to fix.
I see from last year that we also had high winds just before SS in 2011. Guess I should expect more of that in the future. It is calm now but they are expecting fairly high winds all weekend. I will need to clean up my two existing antennas and I hope to hang the 4 element 20m colinear array on my Penninger Tilt-up mast.
Inside, my station is all ready to go for the contest. I have an SO2R setup using the Icom IC-7600 and an Elecraft K2. This year I will also be using some ICE Bandpass filters to try and reduce the Band-to-Band interference I had in past years. I tested the station, including the DX Doubler, last weekend when I operated a couple hours in the CQWWDX SSB contest. I got about 48 Contacts and added a good number of new Countries in the Log.
I really like the SO2R setup with the DX Doubler and N1MM software. I think I have all the technology pieces in place now. Hopefully I can ramp-up the Sweepstakes operation this year. I will be looking once again for that elusive (for me anyway) Clean Sweep. 83 Sections are needed this year for the Broom.
The ZS6BKW Antenna is one of many HF multi-band wire antennas. It is similar to the famous G5RV antenna, which can cover multiple HF Bands but requires an antenna tuner on most bands. The ZS6BKW follows the design of the G5RV, but makes improvements. These improvements allow it to be used on more bands, and to exhibit better SWR on several Bands. There is an excellent article that compares these two antennas, and it shows me that this is a better bet for my station than the G5RV.
I built the ZS6BKW and am now starting the tuning process for my location. I have many trees, so any wire antenna I build needs some pruning, no matter how I model it. I used standard household 14 gauge wire for my antenna and fed it with 450 ohm ladder line. I used the “fat” 450 ohm ladder-line (about 1.5 inches wide), because that is what I have available. My ladder-line uses solid number 14 conductors. That makes it a bit hard to work with, but it holds up very well to the elements at my Bayside QTH.
The one thing I dislike about this antenna is that it is not expected to work on 15 meters, where it has a very high SWR. I can use my 135′ dipole on all bands with my antenna tuner, so I am wondering if this antenna gives me any advantage over that. It is shorter, but I have room for the 135′ wire, so maybe this is a compromise I do not need.
I will be trying it and tweaking the dimensions. I’ll post my results for anyone that may be interested in the ZS6BKW.
After looking at articles in the ARRL Antenna Book and on L.B. Cebick’s web site, I thought a 4-element colinear wire antenna might be useful for my station. I currently use only wire antennas which work fine on 40 and 80 meters, but on the higher Bands, I need some gain. My main goal is to be able to improve my ability to reach Stations in the Northwestern US and Canada. Since this is a bi-directional antenna, it will also help with my DX contacts.
This is a classic antenna design that has been used by many people. I am not claiming to be doing anything unique here. I am just keeping some notes to track my attempts to make this antenna work at my QTH. There is an excellent description of HF Colinear antennas in the ARRL Antenna Book.
Here is the basic design of the antenna
The picture of the antenna above is a little hard to see. It consists of 4 half-wave elements in a line, with two quarter-wave stubs between the pairs of elements. Each stub is a piece of ladder line, with the end shorted. This provides the necessary phase shifting to align the half-wave sections to provide gain. The antenna is fed at the center and the feedpoint impedence is near 450 ohms.
In case anyone is interested in experimenting with the EZNEC model, here is the listing of the wires for this antenna.
Note – this is just one trial set of element lengths. It may not be ideal for any particular location, and may not even be the actual dimensions I use in the final antenna. But if you have EZNEC, you can take it from here and see what works for you.
I like to try a new antenna every year for one of my favorite contests. A year or two ago I had great hopes for a 20 meter Colinear wire antenna in the ARRL CW Sweepstakes. I ran out of time and threw one together quickly. It did not do much for me, but I think the implementation was really poor.
So I am going to give it another try. This time I am modeling it with EZNEC. I started a model last go-round, but never really got to the point that the dimensions were very good. I suspect I was not getting nearly the gain it promises.
There is a good write-up in the ARRL Antenna Handbook about this antenna. If you have any interest in HF antennas, and you do not have this book, what are you waiting for? This is the definitive practical reference book for HF (and VHF/UHF) antennas. My other favorite antenna reference is the LB Cebick (Silent Key) Web Site. LB was a prolific author and antenna enthusiast. I have purchased several of his antenna models and some of his books. This is very practical stuff, and extremely easy to read.
My 20 meter colinear will use four half-wave elements. The goal is to get a decent signal into the far Northwest of the US and Canada. That has always been my biggest difficulty in trying to work all Sections in the Sweepstakes.
I did a bit of testing with 2 wire antennas this weekend. Here is a summary of the results, which I also posted to the IC-7600 e-mail reflector:
1 – A “long” 80m Dipole, ladder line, 4:1 balun, then a long coax run
to the rig
2 – A fan dipole with 80/40/20 meter elements (these are close-spaced
elements, with 80m and 40m using opposing legs of a single piece of
300-ohm twinlead), 1:1 balun, then a long coax run to the rig
This was a brief test. I tried only 10/15/20/40/80 meters, and tested
only a few frequencies on each band, including something close to the
bottom and top of each band.
The IC-7600 internal tuner was able to tune both antennas over most of
the 10/15/20/40/80 meter bands with the following exceptions:
1 – Could not match the 80m Long Dipole at the high end of 80m or
anywhere on 40 meters
2 – Could not match the Fan Dipole anywhere on 20 meters
The External LDG-100 PROII was able to match all the test frequencies.
The IC-7600 tuner is very good, and tuned most of the frequencies,
including some that appeared to be worse than 3:1 SWR (the stated
spec) on my antenna analyzer.
Please note – I am NOT knocking the internal tuner, and with a little
antenna work (pruning antennas and feedlines – not fun) I could
probably get matches everywhere I need to operate. So, while the
internal tuner is very good, the LDG (which has a nice ICOM interface)
covers a wider range. The LDG was sometimes very slow (10s of
seconds), but once a match is found it is stored and recalled quickly
next time you need it.