HF 101: Making the most of the HF bands at solar minimum

HF 101:  Making the most of the HF bands at solar minimum

The IC-7200 station








Since we are teaching the General Class course right now at my local radio club, the anticipation is building for new General operators, and that means getting on the HF bands.  Yes, one can make use of quite a few HF bands with the entry-level Technician Class license, but let’s face it – most newbies buy VHF/UHF handheld radios or mobile rigs and pretty much stick to FM phone operation via repeaters.  The General Class license opens up plenty of other real estate in the frequency spectrum and has for a long time been considered the real portal to HF operation.

So here we are, ready to help new HF operators open that door to all kinds of exciting shortwave contacts and the prospect of direct worldwide communication.  The only problem is…

…the solar minimum.  

As I write this in October 2018, we are at the point in the sun’s average 11 year cycle of activity when the solar disc is mostly free of sunspots.  More sunspot activity near solar maximum is associated with good HF band conditions for ham radio contacts across the globe. At maximum the ionosphere becomes more ionized and the maximum usable frequency (MUF) gets higher.  For example, at solar minimum, the MUF may be disappointingly low, with the 14 MHz band (20 m) being barely usable and all the frequencies above that simply being closed to long distance contacts.

We typically talk about the HF bands using their approximate wavelength, so to avoid confusion let’s recall that the longer the wavelength (higher number), the lower the frequency associated with that band.  Here is how it works out:

Wavelength = Frequency

160 meter band = 1.8 to 2.0 MHz

80/75 meter band = 3.5 to 4.0 MHz

60 meter band = 5.X MHz (channelized)

40 meter band = 7.0 to 7.3 MHz

30 meter band = 10.1 to 10.15 MHz

20 meter band = 14.0 to 14.35 MHz

17 meter band = 18.068 to 18.168 MHz

15 meter band = 21.0 to 21.450 MHz

12 meter band = 24.89 to 24.99 MHz

10 meter band = 28.0 to 29.7 MHz

A complete graphic chart is available at ARRL for download and printing.

General Class licensees will have access to at least some portion of all of the above bands.  Some, like 160 meters and 10 meters, allow Generals the same privileges as Extras! Others, like 20 meters, have specific segments devoted to license class.  Let’s take a look at the two bands that bookend our list: 160 and 10 meters.

Tuning across the 10 meter band at solar maximum can be a delight.  The band is often open to worldwide communication, and because it is one of our most expansive bands, there is plenty of room to call CQ.  At solar minimum that same band is pretty much dead from one end to the other, with a few exceptions when there are local communications via ground wave or when there is summer “sporadic-E” propagation, usually within 1,400 miles.  But trust me on this – the 10 meter band isn’t worth much during solar minimum, and even less in the non-summer months of solar minimum.

The 160 meter band is a different story.  It’s not that affected by the solar cycle and it is at its best in the winter, when the long nights tamp down thunderstorm interference and ionospheric (skip) propagation can allow for long distance contacts.  

Sandwiched between the extremes of the 10 and 160 meter bands are the rest of the HF frequency segments on our list.  As a rule of thumb, those closer to 160 meters are going to be more useful during times near solar minimum, while at solar maximum the bands closer to 10 meters will be the go-to places for worldwide communications.  Bands in the middle, such as 20 and 30 meters, can be useful throughout a solar cycle but will definitely be better at solar max. The 40 meter band is generally open to somewhere 24 hours, but it is not a band with a huge spread of frequencies and it has traditionally been plagued with shortwave broadcast stations.

Let’s cut to the chase.  It’s quite likely that a newcomer to HF will be disappointed with the static and noise across the spectrum.  You need a strategy to get through solar minimum. Here’s what I suggest:

  • If you don’t hear anything but noise when tuning across various bands, don’t assume that you are doing something wrong.  Occasionally geomagnetic storms do engulf the Earth, even at solar minimum, and they can close all of the bands. Be patient and conditions will improve, usually in 12-24 hours.  
  • Try the 160, 80/75, and 40 meter bands, especially when the popular 20 meter band seems dead.  
  • Certain bands, especially 160 and 80/75 meters, are best at night.  Daytime (especially in the summer) is especially bad on these bands, but they do open up at night as the sun goes down.  Plan to do more of your operating on them in the evening or early morning.
  • Even if you don’t have an antenna that will tune for transmitting on 160 meters, you can still use whatever antenna you have to receive on that band.  Tune across the band to find out if you can hear other stations. Use the same strategy for 80/75 meters and 40 meters.
  • Wire antennas are your friend at solar minimum.  If you can put up a wire antenna that can be tuned to transmit in the 80/75 and 40 meter bands, you are almost guaranteed to make contacts.  160 meters is a bit tougher, since as the wavelength gets longer, so does the ideal length of the antenna. There are ways around this, like adding a coil of wire to increase the electrical length of a shorter wire antenna.
  • Vertical antennas can be base-loaded with a coil to increase their electrical length, allowing them to tune on 160, 80/75, and 40 meters.  Almost any yard can accommodate a vertical antenna.
  • Consider using an HF remote station, using the free RCForb software from Remotehams.com.  Both stations W0EQO and W0ZSW, maintained by SARA volunteers, have wire antennas that can tune 160 through 6 meters.  SARA members and Handiham members may request transmit access to these stations. I also give remote transmit access to my own station, WA0TDA, to operators who have at least a General license and who request it.  Remote HF can be another useful tool in your ham radio toolbox, useful for bands where your own antenna won’t tune or a way to get on the air when you are traveling.
  • Use the internet for information on space weather and band conditions.  Two sites I recommend are Spaceweather.com and the N0NBH Solar site.  If you have an Amazon Echo, you can enable the propagation report skill via the Alexa app, then you will be able to get the N0NBH report by saying, “Alexa, start propagation report”.   The N0MBH solar report is also available on many ham radio websites, including QRZ.com.
  • Take advantage of club nets, on the air get-togethers, and special events on the air.  There will be more stations on during these times, increasing your chances of making more contacts.

I hope these strategies are useful to you as you begin to explore the HF bands.  This particular solar minimum (2017 through 2021) has so far been pretty hard on band conditions.  Don’t be discouraged, though – openings can happen anytime, and the more familiar you become with the various bands, the more contacts you will make.  

Now, get out there and have fun on the air!

Posted in Uncategorized | Leave a comment

WA0TDA Station Updates: CW function returns with new host PC

As CW users have noticed, the CW feature has been absent at WA0TDA for a while.  It has returned to service with the upgrade to a new host computer, a new mini-PC from Amazon:

“N34 Mini PC Celeron Processor 4GB DDR3 RAM, 64GB eMMC, DIY SSD, Ultra HD 4K Intel Quad Core CPU up to 2.2GHz, 4W SDP, 1000M LAN, Dual Band WiFi, BT 4.0, HDMI&VGA”

This new PC comes with Windows 10 installed, but Linux is also an option.


Mini PC: Host computer for WA0TDA HF remote

Posted in Uncategorized | Leave a comment

July 23, 2018: Remotehams.com Website

Mouse pad & mouseThe Remotehams.com website has moved to a new server.  Remote stations are functioning normally, and the website is now available again after a short outage.

Posted in Uncategorized | Leave a comment

Check the WX at WA0TDA

Find out if there are storms in the vicinity of Woodbury, MN, in which case the station may be temporarily shut down to avoid lightning damage.

Link to the WA0TDA WX station on Weather Underground.

Posted in Uncategorized | Leave a comment

The stuff you find

duplex outlet meant for AC but wired with TV antenna wire instead

Someone had wired this duplex electrical outlet with 300 ohm TV twinlead antenna wire.

Most of us in Amateur Radio get called on to do tech repairs of one kind or another. It’s like being the kid in your class who knew how to run the projector, right?

Anyway, last Thursday we spent the day helping XYL Susie’s sister get some of those jobs done. They did the curtain rod hanging, while I was assigned to “electrical” and A-V.

After hanging a new chandelier and unboxing and configuring a smart TV, I started on the wall outlets – 1950s style without the grounding socket. Odd how there were two of them within three feet near a window. After changing one of them out and testing it, I pulled the next one out and this is what I found – a duplex outlet wired with ancient 300 ohm TV twinlead!

Since the outlet had measured zip for voltage, I can only assume that someone had used it as a TV antenna outlet. Talk about not paying attention to impedance matching! It was removed and replaced with a blank wall plate.

Anyway, while I missed my radio club’s Thursday Radios in the Park (we got home just before 9:00 PM), it was fun to discover this, um, “creative” use of two electrical items that should never be used together – and to once again be the alpha geek.

Posted in Uncategorized | Leave a comment

Be careful with digital modes on the remotes

Mouse pad & mouseDigital mode operation has really come into its own this solar minimum.  As with any mode, there are some best practices to learn and follow when operating.  While digital modes are fairly straightforward when you are operating with your own station interfaced to your own local PC, it is not so easy when you are operating through a remote HF station.  There are plenty of compromises that you have to make – workarounds to deal with audio in and out of your PC, how to manage switching between transmit and receive, and with modes like FT-8, the critical nature of timing.

About all I can suggest is that you do your homework:

  • Check YouTube for how-to tutorials on each new mode you want to try.
  • Make a checklist because there are lots of steps to have to go through in setting up software and hardware.
  • Once you are ready, always check the rig’s mode of operation (often it should be set to USB) and transmit power output (usually MUCH less than the full power the rig is able to produce.)
  • Read the support forums at Remotehams.com for further setup and operating advice.

What to avoid:

  • Do NOT operate the radio at 100% transmit power when using digital modes!  Not only is this a bad practice that clutters the band, but it REALLY STRESSES the rig’s final amplifier.  Failing to lower the power level can get you banned from TX on HF remotes.
  • Please don’t leave the radio in some oddball configuration that will confuse the next user.  If you lower the power level, return it to 100% when you are finished.  If you activate the SPLIT function, turn it off before you leave.  If you set the RF GAIN down, return it to 100% when you are done.
  • Out of band usage: Please use the radio for ham band operation.  It is intended for ham radio use.  Of course the transmitter only activates in the USA ham bands (with some restrictions, mainly because of antenna limitations, depending on the remote station’s configuration), but the receiver can tune a much wider range.  We have had some issues with users who leave the receiver outside the ham bands and regularly tying it up by using it for SWLing when licensed users would like to use it in the ham bands.
  • Hogging the radio:  Please disconnect when you are finished.  Share with others who want to use the radio.  Pass the mic if more than one user connected.
Posted in Uncategorized | Leave a comment

W0ZSW users welcome to use WA0TDA

Update:  As of 14 June, WA0TDA and W0ZSW are now on their own antenna systems.  WA0TDA uses the maypole inverted vee system, while W0ZSW uses an end-fed zepp for operation on 160 through 6m, with 17 & 12 m excluded.

Please feel free to request WA0TDA transmit access if you have at least a USA General Class license and want to try a remote HF radio!

Dual position antenna switch

The manual antenna switch at W0ZSW is used to switch in the dummy load during testing.

What happened:

Summer chores…   All the stuff that can’t be done in the winter gets pushed into the nice weather months here in Minnesota.  The snow is gone, the days are getting long, and it’s time for yard and landscaping work.  This summer that includes tree trimming and removal – and that poses a problem for the W0ZSW antenna system, a 270 foot dipole that runs through no fewer than seven trees at the WA0TDA QTH.  Five of those seven trees are either going to be trimmed and shaped or removed altogether, so of course the antenna had to come down.

Station W0EQO in northern Minnesota was not affected by this work and remains available.

Contect wa0tda@arrl.net for WA0TDA station access or to report problems with W0EQO and W0ZSW.

Have a GREAT summer, everyone!

Posted in Uncategorized | Leave a comment

Summer antenna work

The hard line coax emerges from the earth at the base of the HF9V vertical antenna, connecting to a 75 ohm matching section.

The hard line coax emerges from the earth at the base of the HF9V vertical antenna, connecting to a 75 ohm matching section.









Alas, I have had to remove a 270′ W0OXB dipole antenna which ran through a half dozen trees on the property.  The reason is that one of the trees is being taken down, and three of the others are being heavily trimmed and shaped.

This leaves a choice of either the Butternut HF9V vertical antenna with lots of radials beneath it, or the inverted vee maypole system.  Both are fed underground with direct burial coax and both cover 80 through 6 meters.

When you log on to the station, the popup message will tell you which antenna is in use that day.

Posted in Uncategorized | Leave a comment

Trading winter snows for summer woes

HF9V vertical antenna in the winter

HF9V vertical antenna in the winter

It wasn’t but a few short weeks ago that the backyard looked like this – snow everywhere.  Then as suddenly as the flip of a switch, the Twin Cities greened up and the snow was gone.  April, usually a rainy month, was a snowy one, and spring tried really hard, but instead of rain we had thundersnow.

Now that spring/summer seems to be here for sure, we can expect more of that lightning and thunder – and that means more shutdowns of stations W0ZSW and WA0TDA, which are both on the same property.  Antennas are disconnected when lightning threatens to minimize damage to the stations and the connected computer network.

Sometimes the thunderstorms pop up unexpectedly as the air warms and rises over southern Minnesota.  This can mean that the stations will be taken offline with little or no notice.  Other times the passage of a frontal boundary will be well predicted and the stations can be shut down in advance of the front’s arrival.

Thunderstorm activity will cause loud static (QRN), especially on the lower frequency HF bands.  When you hear loud cracks and pops on the bands, you may want to finish up your QSO in case the station needs to be shut down.  In the evening or early morning  QRN may skip in from storms in the southern part of the USA, and this is not concern for station damage in Minnesota, though it may interfere with your QSO.

Have fun with the stations and enjoy a GREAT, safe summer!

73 – Pat



Posted in Uncategorized | Leave a comment

Failure Reporting

3.925 MHz on the IC-7200


It is possible for remote stations to have a partial failure – the station will appear when a user logs in, but although the interface is responsive for frequency changes and other settings, there is no audio.  This means that the audio server has failed, and the RCForb server application needs to be halted and restarted on the host computer.  Only a station admin can do this, so please be sure to email wa0tda@arrl.net to alert me.  If I don’t hear from users, the station may remain out of service, so I really appreciate your help with this.


73 – Pat

Posted in Uncategorized | Leave a comment