April 28, 2018
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I ran the 2el vertical beam antenna on 20m WSPR for most of the last week. This time I looked at the WSPR challenge data as compared to N5CEY’s station about 15 miles away. During the week we both made the WSPR challenge scoreboard. On some days I had a higher unique count while on others N5CEY did. The WSPR Challenge site provides a list of all the stations heard in a 24 hour period along with their counts. This can be downloaded and sorted to see which stations had the highest counts. The data for a specific station can then be downloaded over the time period. Here is the count comparison:
Here is a plot of the reported SNR vs time to K8JBV in Ohio from both my station (red) and N5CEY (blue):
This chart is fairly typical and shows that N5CEY has about a 6dB higher SNR at his station vs. mine. I did note at least two stations, one in Georgia and the other in Florida, that had SNR roughly equal at the two receiving stations. This correlates well with the direction I have the vertical beam pointed. Likewise stations on the backside of the beam have a few dB more separation.
I am pretty happy with the performance of the vertical beam antenna overall. What I would like to do next is operate portable from a more rural location and measure and differences in SNR on WSPR.
March 19, 2018
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Previous posts have reported on WSPR performance with my vertical antennas especially compared to data collected by a nearby Ham (Cliff – N5CEY) with a similar antenna setup. The metric is how well a given antenna receives unique spots over a 24 hour period as documented by the WSPR Challenge site. I have always seemed to lag behind Cliff’s receive performance in spots and in DX received. I have asked Cliff about the specifics of his setup and came to the conclusion that he has a significantly lower noise floor at his QTH in the country versus mine in the city. Cliff’s QTH is about 12.5 miles north of mine in a rural area. He is closer to the coast and likely has much better soil conditions as well. His antennas on WSPR are all 1/4 wave verticals on 40m, 30m and 20m. I have an “ugly” balun installed at the feed point of my vertical and about 30 feet of RG-8X to the shack entrance. There are about 8 loops of coax at the shack entrance. Inside the shack are various patch cables connecting switches, antenna tuners, SWR meters and the Timewave ANC-4 to the IC-7300. Lots of nearby noise sources including PC’s, cable modems, wifi routers etc.
So the task before me is how to lower the noise floor at my QTH to bring in weaker signals. I have done quite a bit of research and finally came upon some discussion of the effects of Common Mode currents on noise floor. My next post will detail some measurements on various common mode current chokes but for now suffice it to say that changing my common mode choke arrangement has had a positive effect on the noise floor. Here is what I did:
- Added a CMC consisting of 12 turns of RG-8X around a FT240-43 toroid core right at the IC-7300 antenna connection. This resulted in a 1 S (6dB) unit reduction in the received noise!
- Replaced the ugly balun with a choke as above. No significant change noted in noise floor.
- Replaced 30 feet of RG-8x feed line to the shack with 30 ft of RG-213 coax. No significant change in the noise floor was noted. this change should help in reducing losses though.
Adding the choke to the antenna input made a big improvement in lowering the noise floor. I adjusted the Timewave ANC-4 to further try and negate any remaining noise.
So the results are as follows after 20m WSPR was run for 24 hours:
Pulled ahead of N5CEY by 8 unique spots and made the DX list still lagging a bit behind Cliff. Here are my spots during this period (right image is Cliff’s and the one on the left is mine):
So all in all a significant improvement by addressing Common Mode Currents. More on the Chokes in an up comming post.
February 7, 2018
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I took out my homebrew Buddistick over the weekend to test its performance versus the full size verticals I have been playing with. I haven’t really deployed this in some time so I was able to make some comparisons to some of the antennas I have been working with lately, namely the 1/4 wave ground mounted verticals. Setup up was about as easy as I remembered it but certainly more complicated than the ground mounted vertical. It is also heavier than I remembered it to be. I had it setup with three guy lines and a single elevated radial and it tuned to 1.46 SWR on the 20m band. On 20m it is not a full size radiator and relies on a small coil to bring it to resonance.
Performance was actually quite good on 20m WSPR. Two days in a row I made the WSPR challenge board. It still remains about 20 spots below the nearby station of N5CEY. The number of spots on 1/2W transmit was about equal to the number of receive spots which I am finding to be a good indicator of antenna efficiency. Thais tells me what I already knew, that is, it is a good QRP field antenna.
The antenna went up Saturday afternoon and stayed up through Monday afternoon. Monday it got breezy here at the QTH. Wind speeds picked up to around 20mph with gusts to 35mph. At some point, the camera tripod failed at the point where the PVC pipe meets the tripod. The whole mess came down hard. Fortunately, the whip was spared any damage and the tripod can be repaired.
For my next trick I am going to try and replace the whip with a fishing pole and wire with an elevated radial. Should be much lighter. It has also proven to be much more resistant to the “valley Wind Machine” that builds up around here this time of year.
May 29, 2017
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I have been keen on using WSPR data to compare the performance of antenna systems. I haven’t worked out a detailed metric but I thought I’d share some thoughts on how the data can be broken down. When looking at 24 hours of WSPR data on a specific band I am seeing the the number of unique stations received is a clear indicator of the antenna’s overall performance and pattern. If this is enough to make the WSPR Challenge board for that period then another clear indicator. As an example, the homebrew Buddipole on 20m (even with resonance being outside the band high) came in at #22 on the WSPR Challenge site with 143 unique stations. I have been hard pressed to make the WSPR Challenge board with the end fed horizontal or the magnetic loop antenna (indoors). So the higher then number the better.
The number of stations hearing me on WSPR is a different story. The ratio of stations heard to stations hearing me is rarely equal. This really depends on the efficiency of the antenna, something that is not evaluated on receive. If I transmit at 1/2W I can expect fewer stations received than if I transmit at say 1W. This will not be a linear increase. What I am seeing is that some antennas have a high count of “heard by” stations for a given power than others. This gives a relative indication of the antenna efficiency. There may be a way to correlate this with a given antenna by testing at different power levels.
April 15, 2017
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Overall I am very impressed with the 40m performance of the 1/4 wave vertical. For grins I am running 20m WSPR by running through the antenna tuner. The tuner found a match and after only 8 hours had enough unique receives to make the WSPR challenge yesterday. The count is now up to 123 and I expect to be on the board again with a very decent showing. I will continue testing on 17m then over to 80m and 160m. Not expecting much on the low bands but am interested in the results. I am not going to run on 15m because it is resonant on that band as a third harmonic to the 40m primary. I’ll leave 12m and 10m on the DXxtreme as that antenna has proven itself well on those bands (when they are open).
March 15, 2017
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The vertical end fed antenna using the 9:1 matchbox and 30 feet of wire has looks like a winner on 40m WSPR. It did not make the WSPR challenge board but has shown a respectable 120 unique contacts and a nice spread of DX stations.The mast has held up nicely with a bit of electrical tape at the joints. Here is the 24-hour WSPR map:
March 6, 2017
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I have been running experiments on various antennas this week on 20m WSPR. NO5V is my current base antenna, the Ultimax DXtreme 53 footer up about 20 feet and horizontal. NO5V/1 is the EFHW tuned for 20m and NO5V/2 is the same wire as the EFHW but run as a non-resonant end fed with a 9:1 matchbox and about 30 feet of coax as counterpoise. I am also able to compare this data with that from N5CEY who is running a 1/4 wave vertical at his QTH about 20 miles from here. I will be looking at formally crunching the data but what is apparent is that the current base antenna is not as sensitive on receive as the vertical antennas. This is based on the WSPR Challenge results and A vs. B listening tests. The verticals are nearly equal in receive capability with the EFHW marginally the best. Both of my verticals compare well with N5CEY’s 1/4 wave vertical but he still seems to have a slightly more sensitive system as he gets better signal reports on WSPR from more DX stations.I plan to setup my own 1/4 wave vertical this week to evaluate before I turn my attention to the S9V31.
I did a quick test on 40m in the NO5V/2 configuration and was getting good 40m results as well.
March 1, 2017
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I am now testing a variation of the end fed antenna on 20m WSPR. I am using the same length of wire as the EFHW but am now using the 9:1 matchbox. I have 50 ft of coax running to the shack where I am using an autotuner to match. I have an air choke of 6 turns of coax not at the feedpoint but at the shack entrance. This configuration uses the feedline coax as counterpoise.
So far results are very similar to the EFHW but I will wait for two days to collect the final data. Meanwhile, I am going to require the EFHW matchbox to try and get a better match to try again.
March 1, 2017
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I got the travel mast back up and this time added some electrical tape to help keep it from collapsing. It has been fairly breezy here this week with gusts up to 15 to 20 mph which plays hob with keeping the mast deployed. I am running the 20m EFHW with on WSPR as NO5V/1 with 500mW. I have run this configuration for two full days and made the WSPR challenge list on both days. I am comparing this data with N5CEY which is a nearby station running WSPR recieve only with a 1/4 wave vertical. Here are the results:
2/27/17 – #46 with 116 unique stations recieved vs. N5CEY at #42 with 121 unique stations
2/28/17 – #46 with 122 unique stations recieved vs. N5CEY at #40 with 130 unique stations
I should note that the mast partially collapsed about 4-6 hours before 00:00 UTC on the last day and I lost about 6 feet of mast height. There did not seem to be much of a difference in performance with WSPR. When mapped N5CEY is clearing getting more DX spots. This is interesting because a 1/2 antenna should do better at lower angles than a 1/4 antenna. I suspect that I have some losses with the EFHW matchbox in terms of lossy wiring which I am going to address today and then retry
February 25, 2017
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Back in December, I setup the 20m EFHW antenna up as a 20m vertical and was able to make enough unique receive contacts to make the WSPR Challenge board.I have not since reproduced this performance. Today I started from scratch in a way. I first checked the matchbox I had built previously and confirmed the capacitor setting for 20m. This was dead on as before with a 3.9k Ohm resistor. Next up I replaced the 20 gauge wire with 16 gauge. This required about 30.5 feet to start out with . I setup the travel mast and the wire and then pruned it to resonance on the 20m capacitor position. I wired it up and immediately started seeing good performance on SSB compared to the end fed wire horizontal. There was a marked improvement in received signal strength. Running about an hour on WSPR showed 50 unique receive spots. Running JT65 is showing my signal making good rounds to Europe, South America and Japan.
I am going to play with this setup awhile and then turn it over to WSPR overnight and see how it does.
UPDATE: Should note that I made an SSB contact in South Carolina today and received a S9+10dB for the first time using this antenna. Right around dusk the travel mast collapsed and it was to dark to fix…sigh