Operate an amateur radio station from anywhere with an Internet connection.

Category: Antennas

Antenna tuning affected by wet weather

Dipole antenna with ladder line feed

Most HF remote base stations use some kind of multiband wire antenna.  Often these wire antennas must go through and be supported by trees, especially if the antennas are really long and have to be fitted into limited space.   For example, a half-wave dipole antenna for the 75 meter phone band will be in the neighborhood of 120 – 125 feet (36 – 37 meters) long.  That amount of wire often will need to be threaded through trees to make in fit into the space available.

Although insulated wire is used for the radiating length, the wire is going to be in contact with foliage and branches at some points along its length.  As long as the weather is dry and the branches and leaves are not wet, this arrangement works pretty well.  It’s when the rain, snow, and ice begin that we see the antenna get detuned by the moisture and increased coupling of the radiating wire to the branches and foliage.   Although the insulation on the antenna wire blocks direct current, RF energy is easily passed from wire to tree, especially in wet weather.

With this extra loading, the antenna will no longer be “in tune” with the usual automatic antenna tuner memories that work so well in dry weather.  It will be necessary to run the tuning cycle again, sometimes more than once, while observing the SWR reading on the radio interface.   Often the band will come alive with received signals after this new tuning cycle is complete.  This is a good indication that you are on the right track, and as long as the radio does not return a “HIGH SWR” notice when you transmit, you should be good to go on that frequency.

When the weather dries out, the tuning will revert to normal, so be sure to run the tuning cycle again and make sure the SWR reading is low once again.



W0ZSW returns to service after antenna change


The W0ZSW station with IC-7300 & LDG tuner

W0ZSW was offline for antenna maintenance and host PC updates.  It has returned to service with an inverted vee maypole antenna and has been tested on 160, 80, 40, and 20 meters. Antenna tuning may take longer than usual on frequencies that the LDG AT-1000 PRO tuner has not already memorized. Frequencies that it “knows” will tune almost instantly. Please let me know if you run into any problems with antenna tuning.

The old antenna system will be taken down soon and reconfigured later this summer.  It had suffered decreased performance after it had to be partially taken down and moved for tree trimming last year. Plagued by a high noise level, it was clearly underperforming on receive and would need to be relocated.  There is no particular timeline for this project, nor have I decided on exactly what will replace it.  However, the inverted vee maypole, formerly service the WA0TDA remote, is working very well and is much less noise-prone because it is well away from the house, fed with buried coax.  Users should notice quite an improvement.

The WA0TDA remote is still on the air with an enhanced Butternut HF9V vertical antenna, ground mounted with buried radials and fed with underground hard line. It is also an excellent antenna system, but users will notice the different characteristics of a vertical antenna.

Unfortunately, this means I have no antenna for my IC-706M2G digital station at the moment.

March 29 – First thunderstorm outage of the season

Stations WA0TDA & W0ZSW went offline late in the day on March 28 and remained out of service on the morning of Sunday, March 29.  This was an orderly shutdown to preserve the station hardware from lightning damage as thunderstorms moved through Minnesota.  Lightning strikes were detected within 1.3 miles of the stations.

Both stations will return to service before 9:00 AM CDT Sunday, by which time the antennas will have been reconnected and the systems rebooted.

This is a good time to remind users that shutdowns for thunderstorms may occur without notice now that the season has started.

January 2 – 3: W0EQO online; W0ZSW online; WA0TDA online

Icom IC-7200

The IC-7200 station

W0ZSW is online.  The Windom antenna is in place and the station is working great.  Users will note that this new antenna is a great performer, much quieter than the old one because the feedpoint is well away from any buildings with their noise sources.  80 – 6 m operation. 

WA0TDA is available. Contact me at my ARRL address to request access.  160 – 6 m operation. 

W0EQO is online. Thanks to Bill, N0CIC, for his help at the station location.  160 – 6 m operation. 

Check out the Blitzortung lightning map here. Thunderstorm season is spring through fall in Minnesota, but storms can happen even in cold winter weather!   Storms can pop up quickly, and when they do, the stations may be shut down in order to allow the antennas to be disconnected so as to avoid lightning damage.  There may be little or no warning, but the stations will return to service after the storms pass.  This is just an inconvenience we have to live with, especially during the late spring and summer. 

Remember:  WA0TDA, W0ZSW, and W0EQO all accept multiple users at the same time!  Please do not log off because someone else is already connected.  You will be able to hear both received at transmitted audio at all times.  You can take turns transmitting, assuming you are all okay with staying on the same frequency together.  The first station logged on is the one controlling transmit by default.  Use the “ASK” button to request transmit.  If you want to change the frequency, be sure to text and ask for permission to do so from the other users.  

W0EQO is located in northern Minnesota, near the headwaters of the Mississippi River.  W0ZSW & WA0TDA are located in the Minneapolis – St. Paul East Metro area.

You can browse the worldwide list of Remotehams-enabled stations that are online here. 

Check out the Blitzortung lightning map here.
Please remember that sometimes the stations may need to be shut down with minimal notice when thunderstorms are in the area of the antennas. This is done to prevent lightning damage to the equipment.

Don’t hear anything?  It may be HF propagation.

The IC-7200 station