Tag Archives: Propagation

Post Field Day Report

I got a late start to field day this year due to a late breaking family commitment. Our club tried to setup at the local weather station but cancelled operations due to a large noise source crashing the bands at that location.

I started operating about 19:30 UTC. I started at 5W on SSB but over the first hour only made one contact. The band conditions were not good on 20m with lots of QRM and QSB. I added the amplifier and started to work on 45W. My power draw was significantly higher but my Q rate increased. The solar panel kept up with the power consumption even though there was quite a bit of cloudiness. I continued to operate on 20m until dusk when I switched to 40m. Overall I made 60 Phone contacts over the course of about 8 hours. My score this year will be lower even with more Q’s due to the higher power I ran. I did not get a chance to run digital.

What worked:

  1. Digital logging – netbook needed one charge cycle during this period. The 12V to 18V DC-DC converter was running at abou 2.2A during the charging cycle. I used a 7Ahr for this through a spare Solar Charge controller. I am going to look at a tablet for next year.
  2. The EFHW antenna worked great on 20m.
  3. SOTAbeams travel mast + TV tripod worked great to support antenna with no guy lines.
  4. Solar generator box had enough juice to supply the day’s activity even at the higher power consumption and had some power to spare.
  5. Tube Tarp came in real handy as shade. Luckily no rain on Saturday. I’ll do better with the depolyment next time as I figured out how to guy it better.

What did not work so good:

  1. Can’t run digital mode while using an amp. The amp uses the ACC port on the radio but provides no pass through. I am looking at how I can accomplish this for next time.
  2. I don’t have the battery budget to run 45W phone for 24 hours. I figure I would have run out of power after about 12 hours. Partly cloudy day didn’t help.
  3. Didn’t take advantage of more 6 stations to raise Q count.
  4. Calling CQ consumes a lot of power. Need to refactor the power budget.

So I figure my score this year for 60 SSB QSO’s + bonus points for emergency power will work out to 310 for my 1B station. I am convinced now that I have to finish learning CW so that next year I can run 5W on CW and up my point count. A more directional antenna would be nice but a portable beam antenna remains elusive. For some reason I seemed to be doing better with stations in California than on the more densely populated east coast.

In summary, A great afternoon of outdoor radio fun and already looking forward to next year.

Field Day Antenna Selection

Working on Field Day antenna selection this week. I am down to using the Homebrew Buddipole, Buddistick or end fed vertical antenna this year. I plan to operate as 1B battery operation so I am limited to 5W on SSB. This will be my main challenge  this year given the worsening band conditions as the solar cycle continues the drop.

A previous post showed some data on the homebrew Buddipole mounted at 16 ft with a painters pole. I am working on a few tweaks now that will bring resonance into the band and simplify the azimuth adjustments.

The Homebrew Buddistick served me well in 2015 but band conditions are shifting. Here is some modeling data comparing the Buddipole at various heights vs the Buddistick on 20m:

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The Buddipole at 16ft and 20 ft outperforms the Buddistick down to about 25 to 20 degrees. The Buddistick has more gain below these take off angles. At 30 ft the Buddipole is better or equal to the Buddistick from 60 degrees all the way way down to zero.

One thing I could do is use both antennas and switch back and forth as needed. This would not be overly complex to do. My challenge is getting the Buddipole up above 16 ft. If I can get setup using the military poles I can get the Buddipole up to 30 ft and only use the one antenna.

 

 

Working 40m and 17m this Weekend

I reconfigured what has become my main antenna, the 40m 1/4 wave vertical. This is still a temporary installation but I am growing increasingly happy with the results I am getting. I frankly can’t remember the last time I used the horizontal end fed. I have had to roll up the radials on occasion to mow the yard and have not yet deployed my permanent radials. Currently I am using the 30 foot travel mast from SOTAbeams to support the vertical wire and have four 27 foot radials deployed. I am using my homebrew 1:1 current balun at the feedpoint and running to the shack with 50 ft of RG-8X.

If I get the chance I’ll start operating around 6:30 am local time on 40m JT-65. I can usually snag several contacts in Japan with the occasional contact into Australia, Indonesia or the Philippines. The action is over by about 7:30am local time as the band closes quickly after sunrise.

Saturday afternoon, I was checking the bands and came across a strong VK station on 17m SSB. We exchanged signals reports in the 54 to 55 range. I moved over to JT-65 and found that there was DX activity including another VK contact. Today Sunday I am finding about the same conditions, great 40m propagation to the far east in the early morning and some light DX into Europe & South America on 17m in the late afternoon.

 

Some Thoughts On WSPR Data for Antenna Comparisons

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.

 

Homebrew Buddipole Shakedown Testing

Sometime ago I built a homebrew version of a Buddipole horizontal dipole antenna. I only deployed it once to test and have not really used it much since. I am considering using this antenna for Field Day this year on the 20m band and wanted to test it out. Happy I did for several reasons. Here is the antenna deployed at 16ft with a painters pole:

Photo May 27, 1 47 33 PM

The antenna is guyed at two levels. The painters pole is inserted into a speaker stand tripod. Here is the SWR plot:

BUDDIPOLE Custom

Most of SWR is below 2 however the resonance point is outside the band on the high side.  So I have to lengthen the antenna slightly. The whips are already at their max so I will have to adjust the loading coils. One more turn on each should give me room to adjust with the whip lengths if necessary.

Something else that needs to be addressed is that the antenna swings around in the wind. I need to add an attachment point for a separate line to secure it from swinging. The old “Armstrong” method of swinging the antenna around. Finally, I need to put a true 1:1 current balun at the feed-point. I have the kit to build one and will do so this week.

The antenna has performed well. I called CQ this afternoon and made 5 contacts from South Dakota to Florida and North Carolina. Band Conditions have been fairly bad with considerable QSB. Europe will open up in a couple of hours and will try it again then.

 

 

Transmit Power Using JT-65

I came a cross a very helpful web page in determining the amount of power needed for JT-65. It is called dbCalc and allows you to enter your transmit power and signal report and then calculates what your report would have been with other transmit power levels. I tried this out today on 40m JT-65, lowered my power in half and still made several DX contacts to Japan and Argentina.  You can easily measure how your signal is doing at a given power by sending a CQ and then checking the Pskreporter reports. Feed these into dbCalc and you can optimize your power settings for given band conditions. I suspect that in most cases operators are using a lot more power than necessary to make JT-65 contacts which makes it harder for weaker signals to get through.

40m QSO’s with 1/4 Wave Vertical

Most of this week was sent collecting WSPR data on the 40m 1/4 wave vertical. The vertical is holding up better to the breezy days after placing some duct tape on the joints of the travel mast. The vertical radiator is a 32 foot length of insulated #14 speaker wire. There are only four 27 foot ground radials deployed at this time. There is a 1:1 current balun at the feed point and about 50 feet of coax to the shack after that. Here is the SWR plot:

swr

SWR is under 1.5:1 across the whole band with a resonant point 7.125 MHz. This antenna has been a solid performer on 40m without a tuner. I am noticing that the band starts opening up to DX about an hour before dusk. Last night I made several SSB contacts with Europe after 10pm local time.

Switching to 40m JT-65 at that time was very interesting as well  as the propagation conditions can be somewhat visualized with pskreporter. I really tested the JTDX software last night and have gotten the hang of the user interface which is subtly different from WSJT-X.  I set the IC-7100 with AGC-off and the bandwidth filter set to 3.6 kHz. Rather than search and pounce, I would look for a quiet spot at the extremes of the band and call CQ DX. This strategy worked well with many European stations answering. Over time, I can see my signals fading on the pskreporter map as eastern Europe’s morning progresses. As dawn approaches in Western Europe, stations start coming online and start to see my signal. At the same time, the opposite terminator starts approaching New Zealand and Australia and my signals starts picking up there as well. I knocked off at about midnight local time and picked up at about 7am and repeated. This time JA stations were answering my CQ and I was running a JT-65 “pile-up” with several JA stations calling at the end of a QSO.

Very pleased with the antenna performance on this band. 20m is acceptable through a tuner but the WSPR data indicates some degradation in performance over a resonant vertical or even the end fed antenna.

Operating this Weekend with a 1/4 Wave Vertical

The winds have died down a bit here at the QTH and the travel mast has been up about a week now. The duct tape on the joints may have something to do with it. On 40m, the antenna is a winner. Made contacts on SSB to Europe in late afternoon early evening on Saturday. Making JT-65 contacts into Japan is like shooting fish in a barrel on early mornings. On 20m, I run the antenna through the tuner and also made some DX into Europe and the South Pacific. I switched between the vertical and the horizontal DXtreme end fed antenna and found that the vertical can definitely hear signals that the horizontal cannot. Propagation conditions seems to be shifting these past couple of weeks. 40m is solid into Asia early morning and Europe in the early evening. 20m has been weak in the morning but picks up in the late afternoon. 17m has been really hurting lately with some small windows opening up from time to time. All in all a good weekend of radio activity.

20m EFHW is Back On The Air!

Lawn maintenance time again and I still haven’t permanently deployed my radials. Took the 40m 1/4 wave down today and picked up the radials.This is a tedious process but not too time consuming. I had the most difficulty in getting the travel mast to retract as it sticks sometimes. Went ahead and setup  and re-tuned the EFHW for 20m as it doesn’t need radials to get hung up in the lawn mower. I am running WSPR as NO5V/1 now to compare against earlier data. I made several USB contacts this afternoon with it. Band conditions were terrible as geomagnetic storms are still raging. The QSB was awful but I did manage to secure a solid 59 into Vancouver.

Saturday’s Radio-activity

Had a good club meeting this morning and chatted on quite a few and varied radio topics. Will be starting the HF voice and Digital Nets next week on 40m at 1pm local time. Voice will be on 7.250 Mhz and MT63 1000L digital following shortly thereafter on 7.060 Mhz. There is a major geomagnetic storm going on now that has impacted the HF bands. Not much in the way of QSO’s going on right now except for JT-65. Good time to play with some other projects.

Tested the new 10Ahr LiFePo4 battery this afternoon with the solar charge controller and a non-radio load (5V USB charger on 12V lighter plug). Pleased to report this battery worked like a champ and is a drop in replacement for the lead Acid SLA batteries. It is half the weight of the 7Ahr SLA battery and can provide at least 80% of its capacity without shortening the life of the battery. So I am replacing two 7Ahr batteries that provided 7Ahr of capacity at about 10 pounds with a single 10Ahr LiFePo4 that can provide 8Ahrs and weights only 2 lbs! Nice!

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I ordered a USB OTG cable from Ebay. This cable allows me to hook up and SDR dongle to an amazon fire with the SDRTouch Android app. The only downside is that you need an external power source to get enough power to the SDR dongle. I hooked it up to the USB charger I was testing with the new battery and it ran fine.

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