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.
June 22, 2017
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I completed the linked EFHW later yesterday afternoon and tuned the 15m, 17m & 20m bands. I removed about 6″ of wire to tune 15m, 2″ to tune 17m and about 3″ to tune 20m. The antenna is deployed vertically on a SOTAbeams Travel pole up 30 feet. I am using a TV mast tripod as a base. In the field I would lash the mast to a fence post or other similar support.
I tested the antenna on my base rig at 100W and made three easy SSB contacts. Two of these were EU DX contacts. I left it tuned for 20m and ran WSPR for the last 12 hours. Here is the map:
This works out to 112 unique heard spots with 66 unique heard by spots when running 1/2W. Looks like the antenna is a winner for Field Day! Only thing I will likely try today is adding a 1:1 choke as I am seeing the SWR swing a bit on SSB transmit.
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 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 7, 2017
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Space weather quarterly has great article on how ham radio operators are contributing to the study of space weather using data collected from WSPR beacons as well as the reverse beacon network.
The article can be read here:
Space weather quarterly
January 17, 2017
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We are sinking into the low period of the sun cycle and the bands have been reflecting the changes. 12m and 10m are largely closed these days. 15m opens sporadically. 17m is ok during the day but isn’t what it was a few months ago. 40m and 20m are the workhorses these days so I am looking at getting an antenna up that will help run on those bands in particular. I was very enthused by the results on WSPR on 20m of the end fed vertical. I am looking at making this a bit more permanent. I have an S9V31+ that has been gathering dust since I bought it. My plan is to set it up here at the QTH. The thing I am going to be evaluating is whether to run it as an end fed or a 1/4 wave vertical with radials. The only reason I am considering the end fed version is that I don’t have a lot of room for radials thanks to some landscaping and pavers in the backyard. I have setup the travel mast again as an end fed vertical using the Ultimax 100 matchbox. I am running WSPR on it over the next few days on various bands to collect some data. I’ll then lay some short radials and run the same length as a 1/4 wave vertical with a 4:1 balun.I expect very similar performance but the data will tell the tale.Whatever works best will be how I configure the S9V31+.
I ran some SSB contacts with it this afternoon on 20m with some good signals reports coming from Nebraska. Also running A vs B against my horizontal end fed was showing about a 2-3 S unit difference in the noise floor with the vertical. I’ll be working to evaluate that as well.
January 8, 2017
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First week of 2017 was not too good here at the QTH. My second amazon branded USB hub died on me this week. This caused havoc again with my digital and rig control setups.These are getting hard to find in local stores so I ordered a 10-port hub from amazon. This one has a nice hefty power supply and is doing the job well.
Tuesday, my cable internet went down hard. Spectrum (formerly Time Warner) did not send a tech out until Thursday noon. Looks like the same issues as usual, i.e. low signal strength from the street. In goes an amplifier again at the cable box outside. They also replaced my cable modem for good measure. No internet means no spots on WSPR or Pskreporter let alone be able to work from home.
I attended my first CW academy class on Tuesday but had issues with Skype as I was using a cell phone hot spot. Got through the session but was not able to attend the second this week due to an unexpected family obligation. Overall, the class is going very well. I am sending better than I can read at this point but keeping up with the daily practice.
December 31, 2016
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I installed a piece of 2″x2″ angle aluminum in the ground outside the shack to support my vertical travel mast. This works very nicely with the tie down straps.
I tested the EFHW on 20m yesterday on WSPR and found that it was hearing and being heard quite well on 1W. I shifted this to the end fed matchbox that I have had for some time. This requires the tuner but allows for multi-band operation. I used the same wire as the EFHW of around 30 feet. I modified the coax arrangement so that the air chock is at the window panel instead of the feedpoint. This gives the remaining feed line as part of the counterpoise. This seems to work well. I am getting reports comparable to the EFHW on 20m with this antenna. I was able to have a good ragchew with a station in AZ on 100W SSB using this antenna. I am keeping this up through 00UTC today and see if I score in the WSPR Challenge.
December 28, 2016
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Finally got around to finishing the 40m magnetic loop antenna. This antenna is designed to be easily deployed and used as an NVIS antenna with up to 100W. The heart of this antenna is the hi-voltage capacitor I designed and previously discussed. Before setting up the new antenna I made a few changes to the capacitor:
- Wrapped exposed copper with electrical tape
- Replaced the steel 5/16″threaded rod with a two food nylon rod. This was to minimize coupling effects while tuning
- Made a new center post with better hole alignment. This helps keep everything from binding.
- Epoxied the capture nut into the center post.
Here is the capacitor in use on the new antenna:
The 40m loop consists of 22 1/2′ of RG-213 coax. The length was selected to match the capacitance of my prototype capacitor. Here is the design points via AA5TB’s spreadsheet:
The rest of the build involved cutting pieces of 1/2″ PVC pipe to length to support the antenna. I hauled the whole thing ip a tree branch with the feed point just about 1″ off the ground. Initially the SWR was a bit high but it settled into about 1.4 when I removed two turns from the toroid. Here is the SWR plot through 50 feet of RG-8X feedline:
Here is a view of the antenna deployed on a tree branch.
I have been running WSPR on 40m now for about an hour and transmitting 1W. Here are the contacts thus far:
This seems to be working well so far. My only complaint is that I have to stand on a ladder to tune it. I’ll need to work on that. I’ll run some additional tests now that its built.
September 16, 2016
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I have been pretty busy lately and have only had short periods of time where I can play radio these past few weeks.
I managed to get the 20m EFHW antenna out as a vertical again last weekend and ran on 45W for about an hour. Had some really good contacts and one short rag-chew. I trimmed the antenna a bit more and got the resonance point into the voice part of the band. This antenna is really working well.
The portable station worked well on a partly cloudy day. I used the 52W foladable panel on this outing and it just kept up with the consumption of the rig. Direct sunlight is definitely a plus.
The 60W foldable panel may have a problem. I am only getting a little over 12V in full sunlight. I will need to check the wiring as I seem to recall it was much higher before.
I setup the Raspberry PI WSPR station on my desk with a short antenna and ran it for 24 hours. My base HF receiver was able to pick up the signal and provide decodes but no other station was able to copy it. I think my next attempt will be connecting it to the Magnetic Loop on 20m. I’ll have to dig around for a suitable cable adapter but I a pretty sure I have one handy in the shack.
Most of my contacts have been using JT-65 and JT-9 on 80m, 40m, 20m, 17m and 10m. The 10m contacts I got lucky with to South America. 17m has been pretty decent to Europe in the mid-morning hours.40m is decent to Australia in the early morning just before dawn (hey, I am an early riser). Most of the activity centers around 40m and 20m.
I adjusted the programming on my DMR radio per instructions that Joe, N5JLR, provided me. No issues with this at all.
I have not worked on the HSMM gear, the 40m NVIS Loop or upgrading my window feed panel due to time. The sun continues to slow up its activity for this cycle. Getting used to working 20m and below and looking at antennas that will be me do just that.