Propagation Prediction Websites

Is 20 meters open to the location of the latest DXPedition on the bands?   When is 6 meters open for Sporadic E?  Looking for a weak signal 2 meter contact with a specific grid square?  There are websites you can visit that give you a prediction of whether the band you are on is open to a given destination.

HF Propagation

N0NBH Propagation Widget

N0NBH Propagation Widget

The simplest HF propagation prediction is the widget that is seen on many Amateur Radio Websites –,, and more.   This gives you a rough idea of what bands are open day and night. Data is based on the Sunspot Number, A and K indices and other indices.  But this doesn’t take into account many factors like your location, the DX location, the characteristics of your station and the DX station.  Just because 15m says Poor doesn’t mean you won’t hear anything on the band.

VOACAP – HF Propagation Prediction

VOACAP Point to Point Prediction

VOACAP Point to Point Prediction

VOACAP, is the Voice of America Coverage Analysis Program, and provides detailed information about the HF propagation.  You can choose transmitter and receiver locations from many cities around the world.  It also provides choices of Antennas, Power, Mode, and more for each end of the contact. You can look at several different views of propagation.  If you spend some time delving into the details of propagation visit this site.

VOACAP Prediction from

VOACAP Prediction from

For a faster view of whether you will be able to contact a specific DX Station that is currently on the air,  the spotting website has incorporated propagation predictions on their website.  If you find a DX station spotted there that you contact, just right click on the DX callsign and select VOACAP from the drop-down.   You just need to choose whether you are a Basic (100 watts and a Wire) or a Super station (Amplifier and Directional Antenna).  You can also look at views of Short Path or Long Path.  It will give you a good view of when you need to be on which band to contact the DX station.

6 Meters – The Magic Band

DXMaps - 6 meter openings

DXMaps – 6 meter openings

The best website that I have found for 6 meters is .  It provides a map view of the world or you can select a continent. Based on spotting network data, it shows 6 meter contacts and color codes them by Sporadic-E, Multihop ES, Meteor Scatter, etc…  even Aurora.  You can also get a view of 10 meters, 2 meters or 70 cm.  If you sign up for a free account, you can subscribe to real time notifications when there is an opening near you.

2 Meter Propagation

VHF Propagation Map

VHF Propagation Map

Looking for a tropo opening for a weak signal 2 meter contact?   Visit the website to see a VHF Propagation map.  This shows tropo openings as color coded clouds – with brighter colors for the longer openings.    This is based on APRS data.

These are the websites that I like to visit to understand the propagation forecast for the day.  If your favorite site is not on the list, add a comment so that we and the rest of our readers can check it out.

DX Alarm Clock Part 2 – Hardware

The DX Alarm Clock

The DX Alarm Clock

I recently wrote a blog article about the DX Alarm Clock software – here is Part 2 of the Series on the how I built the hardware for the DX Alarm Clock.

DX Alarm Clock Hardware Components

The DX Alarm Clock is based on a Raspberry Pi 3 computer and an Adafruit Pi-TFT Touch Screen Display.  The list of components, along with links is below.  Since I built the Raspberry Pi almost a year ago and technology is always advancing, some of the parts are no longer available or have better replacements available.  I’ll provide information on what I used and a recommended replacement.  Approximate prices are included.


Rapberry Pi 3

Rapberry Pi 3


Motherboard: Raspberry Pi 3 ($35) – includes a 1.2 GHz 64-bit quad-core ARM CPU, Build in WiFi, Ethernet, 4 USB Ports, an HDMI port and audio port (3.5″) and Bluetooth.

Also you will need a power adapter  ($10) and Class 10 Micro SD card ($15) for the Raspberry Pi.  Ours is a SanDisk Ultra 64GB Micro SD Card.

Pi-TFT Touch Screen Display

Pi-TFT Touch Screen Display

Display: Adafruit Pi-TFT 2.8″ Display with Capacitive Touch Screen ($45).  A slightly larger, 3.5″ display is now available.

PiBow Case

PiBow Case for Raspberry Pi and Touch Screen Display

Case: Pimoroni PiBow Case for Raspberry Pi and Pi-TFT Display($20)

Kinivo Speaker

Kinivo Portable Speaker

Portable Speaker:  Any small portable/rechargeable speaker will do.  Mine is a Kinivo, but it is no longer available.  Any small speaker will do as long as it is Bluetooth or has a 3.5″ stereo connector.


Raspberry Pi Development Environment

Raspberry Pi Development Environment

Raspberry Pi Development Environment

After constructing the Raspberry Pi, case and TFT Display, the next step was to connect it to a monitor via the HDMI port, a mouse via one of the USB ports and to a Bluetooth keyboard.   Then I loaded the Raspbian Operating System onto the Raspberry Pi via the micro SD card.  I first copied the OS to the Micro SD card using a PC or Mac and then inserted the card into the Raspberry Pi and booted from it.  You can find a good tutorial on how to do this at

Once Raspbian is installed, you will have a windows like GUI (Graphical User Interface) environment with a web browser, and a number of additional applications included.

This gave me a development environment that I could use to build and test the DX Alarm Clock software.  I used the Python language to develop the software.  I used the Python IDLE development environment, which is included in the Raspbian OS.

Interested in Raspberry Pi Amateur Radio Projects?  See the article on a Raspberry Pi Satellite Rotator Interface.

Amazing DX Opening On The 12M Band

12m DX - XT2AW Burkina Faso

12m DX – XT2AW Burkina Faso

Today proved out some simple, tried and true advice for me – it pays to take some time and tune through the bands. I just got a Maestro Remote Control Device for our FlexRadio SDR and I took a break around lunchtime to tune through the higher HF bands to see what I could hear. We use a Flex SDR as a Remote Operating Gateway into our station and the Maestro allows me to run our station over our home network with going down to the shack.

I am not sure why but I decided to give the 12m band a look today. When I did, I was stunned! It is about noon time and the 12m band is wide open between Africa and the US!

I worked two DX stations on 12m SSB. The first was XT2AW, Harald in Burkina Faso. Harald was working split and was not real loud but I had no trouble completing the contact with him. Excited, I tuned across 12m some more and found an old friend – Theo, ZS6TVB in South Africa. I had a very nice QSO with him. We both marveled over the propagation on the 12m band that we were experiencing. He was 57-58 here in New Hampshire!

12m DX - ZS6TVB South Africa

12m DX – ZS6TVB South Africa

The sunspot conditions are pretty weak (SFI 85, SN 26) to create such a good opening on 12m. I believe that we may be experiencing Transequatorial Propagation (TEP) which can provide a significant propagation enhancement on paths with traverse the equator. Anita and I experienced similar TEP propagation on 10m when we were on Bora Bora Island early in 2012 with similar solar conditions.

It just goes to show that it pays to tune the upper HF bands. Especially on days when “they are not open”. Also, 10m also appears to be open to Africa right now – I am hearing a station in Mauritania

Fred, AB1OC

Quicker-Turnaround Digital Modes in Experimental Stage for WSJT-X Suite

WSJT Screen

WSJT Screen

WSJT-X developer Joe Taylor, K1JT, weighed in to express his appreciation to all who shared their ideas and experiences using JT9 and JT65 modes during recent multi-hop E-skip openings on 6 meters.

“We are very much aware that a mode with most of the excellent characteristics of JT65, but with faster turnaround time, would be a big winner in such situations,” Taylor commented on behalf of the WSJT-X development team. “We are experimenting with several such possibilities. Tentative goals include 15-second T/R sequences, sensitivity around S/N = –20 dB, occupied bandwidth less than that of JT65, and capability to decode as many as 10 or 20 signals in a 2-kHz bandwidth.”…

Source: Quicker-Turnaround Digital Modes in Experimental Stage for WSJT-X Suite

This is something to follow if you are interested in the JT modes for HF and VHF communications. Our experience is that a new JT variant that would trade S/N margin for a faster QSO segment speed would be just the ticket on many of the HF bands as well as 6m.

  • Fred, AB1OC

Why Ham Radio?

Scorpion SA-680 Screwdriver Antenna

Fred’s Truck with Antenna

Every so often, I drive Fred’s truck into work and people ask me what that big antenna on the back of the truck is for. I explain to them that it is for Ham Radio.  But the reply is usually, why ham radio – isn’t that outdated technology?  We have cell phones and IM, etc…what do we need Ham Radio for?  So I thought I would put down my thoughts as a relatively new Ham about why I enjoy spending so much of my time with Ham Radio.


Amateur Radio for Public Service

Public Service

The number one reason we still need Ham Radio along with all the other technology we now have is for public service.  When there is a disaster and cell phones, television, etc are all not working, Ham Radio operators provide the critical communication.

Ham Radio operators help locally to keep hospitals and first responders in contact with each other to help those affected by the disaster.

Hams also use our ability to communicate around the world on HF bands to help family members around the world to get in touch with loved ones affected by a disaster.

Ham Radio operators have been on the scene helping in every disaster from the earthquakes in Nepal to the recent flooding in California.


Amateur Radio Cube Satellites

Technology and the Maker Movement

I only became a Ham 5 years ago but many of my fellow Ham Radio operators got their license when they were in their early teens and used what they learned to launch their careers. Many have had very successful careers in STEM fields, all launched by their interest in Ham Radio at a young age.  As technology advances, so does the technology used in our hobby.   We even have a nobel laureate, Joe Taylor K1JT who is a ham. Joe has developed weak signal digital communication modes that let us communicate by bouncing signals off the moon!

As technology has advanced, so has the use of it in Ham Radio.   Most Ham Radio operators have one or more computers in their shack.  Many also have a software designed radio (SDR), where much of the radio functionality is implemented using Software, we use sound cards to run digital modes, which are a lot like texting over the radio, and we use the internet extensively as part of operating.  We can also make contacts through satellites orbiting the earth and even the International Space Station.

Most hams love do-it-yourself technical projects, including building a station, home brewing an antenna, building a radio or other station component.  In my day job, I am a program manager for software development projects, but its been a while since I have built anything. As a Ham I taught myself how to code in Python and about the Raspberry Pi and I built the DX Alarm Clock.


QSL Card from VK6LC in Western Australia

International Camaraderie

One of the coolest things about being an amateur radio operator is that you can communicate with other hams all over the world. Ham Radio is an international community where we all have something in common to talk about – our stations and why we enjoy ham radio.    The QSL card above is from a memorable QSO with Mal, VK6LC, from Western Australia, who was the last contact that I needed for a Worked All Zones award.  I must have talked to him for 1/2 hour about his town in Australia and his pet kangaroos!


Amateur Radio Map of the World

Geography Lesson

I have learned much about geography from being on the air and trying to contact as many countries as I can.  There are 339 DX Entities, which are countries or other geographical entities and I have learned where each one is in order to understand where propagation will allow me make a contact.  I have learned a great deal about world geography. Through exchanging QSL cards often get to see photos from so many areas of the world.


DXCC Challenge Award Plaque

Achievement – DXing and Contesting

DXing and Contesting provide a sense of achievement and exciting opportunity for competition. Many Hams work toward operating awards. You can get an operating award for contacting all 50 states, contacting 100 or more countries, contacting Islands, cities in Japan, countries in Asia, or anything else you can imagine.  Each of these operating awards provides a sense of accomplishment and helps to build skills.  Contesting builds skills through competition among Hams to see who can make the most contacts with the most places in 24 or 48 hours. Contesting also improves our operating skills and teaches us to copy callsigns and additional data accurately.


Teaching a License Class

Teaching Licensing Classes – Passing it On

Recently I have joined a team of club members who teach license classes to others who want to get licensed or upgrade their existing Amateur Radio licenses.  Teaching provides a way to improve my presentation skills and also helps me to really understand the material that we teach about Amateur Radio.  It is always a thrill at the end of the class to see so many people earn their licenses or upgrades.

There are so many interesting aspects of Ham Radio which is what makes is such a great hobby.  Getting your license can open up a world of possibilities.  Upgrading to a new license class provides more opportunities to communicate over longer distances.  Ham Radio clubs, including our local club, the Nashua Area Radio Club,  provide many resources to help you get your first licenseupgrade to a new license class, and learn about the many aspects of our hobby.

The DX Alarm Clock – Part 1 Software


The DX Alarm Clock

I have been a Ham for 5 years and my favorite thing to do is chase DX. As a new Ham it was always a thrill to work a new DXCC, but now that I have over 280 DXCCs and over 1000 band points, it is a little more difficult to find a new one. Add to that the fact that I am trying to get a DXCC in 80m and 160m., which are usually open when I am asleep. I created the DX Alarm Clock as a way to get notified that there is something new on the air when I am not down in the shack.  This article will talk about how I developed the software for the DX Alarm Clock.  Part 2 will talk about the building the Raspberry Pi based Hardware and loading the OS.

The DX Alarm Clock is a Python software program running on a Raspberry Pi that gathers data online about my log and what is on the spotting network and uses that data to alert me when there is a “new one” on the air.


DX Alarm Clock Architecture

The ClubLog website provides a light DX Cluster website called DXLite, which has an XML Interface. The DX Alarm Clock uses this interface to get the current spots. The software uses the Developer API from ClubLog to get a JSON matrix of all DXCC entities by band indicating whether I have worked, confirmed or verified each band-entity. The software loops through all of the spots returned by DXLite and looks each DXCC up in the JSON ClubLog matrix. I also use the XML Interface to get additional information for each callsign that is spotted, like the state.


DXCC Configuration Screen

The DX Alarm Clock uses tkinter/ttk for the GUI.  I used the Notebook widget to create a multi-tab GUI.  There is a tab for configuring filters for DX Entity. The user can choose all New DXCCs, as well as specific bands and nodes to provide alerts for.


WAS Configuration Screen

There is another tab for configuring filters for WAS. ClubLog has no log look up capability based on US State so the WAS filter lets you create a list of States and associated bands to provide alerts for.


Notification Configuration Screen

The Notification tab allows configuration of what notifications the user would like to receive. The user can specify a separate email address for New DXCCs, New Band Points, and New US States. This allows alerts to be sent to email accounts or as SMS texts. You can also configure the sounds the the DX Alarm Clock itself makes to “wake you up” when that ATNO or new Band Point is spotted.

The DXAlarm clock wakes up every 5 minutes and gets the latest spots from the DXLite Cluster. It checks each spot against the ClubLog log and if there is a match based on the configure filters, it sounds the alert, and then speaks the alarm, giving you the Callsign, DXCC Entity, Band and Mode.   A simple text to speech package called flite (festival-lite) was used to implement the speech on the Raspberry Pi.



Alert Screen

It also puts a message with these details and the Frequency, UTC Date/Time, Spotter and Comment on the display.


Text Notification to iPhone

Additionally it sends this information as an email to the configured email address, which results in a text or email.



Apple Watch Alert

I can even get the alert on my Apple Watch.


Filtered Spots Display

Once all spots are processed, it keeps a running list of all spots that resulted in alerts on the main screen. Spots are aged out if they do not recur over time.


DX Alarm Clock Hardware

The DX Alarm Clock just alerted me that ZC4SB is on 20m – that’s an ATNO!  Got to go down to the shack and work him!    Stay tuned for Part 2 of this post on the DXAlarm Clock Raspberry Pi based hardware and on setting up the Raspberry Pi OS.

Anita, AB1QB

Building And Operating A Mobile HF Station

Mobile HF Presentation

Presentation On Building And Operating A Mobile HF Station

We recently had the chance to do a presentation on building and operating a mobile HF station for the Nashua Area Radio Club here in New Hampshire, USA. I thought it would be interesting for our readers to see this presentation as it contains some new information that we have not previously covered on our Blog.

Mobile HF Antennas

Mobile HF Antennas

Safety in mounting mobile antennas and anything else on the exterior of you vehicle is a primary concern. This was discussed in some detail during the presentation. The best source to understand safety considerations and proper installation and mounting of Mobile HF antennas is Alan Applegate’s excellent website,

The most important part of any Amateur Radio Station is the antenna system. This is especially true in a Mobile HF Station because antennas in these applications are almost always short loaded verticals. To create an effective antenna system for a Mobile HF application, one must pay extra attention to the “3 R’s” – Radiation Resistance, Loading Coil Loss, and Ground Loss. Radiation Resistance (a measure of the antenna’s ability to transfer transmitter power to radiated waves) is the “good R” and the other two R’s dissipate power from our transmitter in the form of heat.

Mobile Antenna System Typical Parameters

Mobile Antenna System Typical Parameters

There is some good information on the typical efficiency in the ARRL Antenna Book. As you can see from the table above, the Radiation Resistance of a mobile antenna becomes quite small on the lower bands (40m, 80m and 160m). Also note that as the antenna becomes increasingly shorter to RF on these bands, more loading coil inductance is needed to make up for the short radiator length on these bands. On these bands, Coil Loss and Ground Loss can easily dissipate most of our transmit power in a very inefficient antenna system. The net of all this is that one must pay careful attention to controlling the Ground and Coil losses while trying to make the Radiation Resistance of the antenna as high as possible. One good way to improve the Radiation Resistance of a mobile antenna is to make the whip longer. For more on mobile HF antenna efficiency, please consult

Scorpion SA-680 Screwdriver Antenna

Scorpion SA-680 Screwdriver Antenna With Rod And Cap Hat

Here in New England, we have many low tree branches which limit the practical length of a mobile whip. A good technique, if the installation permits it, is to use top loading in the form of a Capacitance Hat. The Cap Hat makes the antenna appear longer and thus increases the Radiation Resistance of the Rod below it. The increase in apparent electric length at Radio Frequencies also means that less loading coil inductance will be required which in turn also means that the Coil Loss is lowered. This is a win-win. The only problem is that this sort of setup significantly increases the wind load on the antenna when driving so a mechanically strong antenna and mounting system is required for a safe installation. Ground Losses can be minimized by making the vehicle on which the antenna is installed a good RF surface to couple to the ground. This is best accomplished by proper Bonding of the metal surfaces on the vehicle to each other and the vehicle’s frame is there is one.

Mobile HF Equipment

Mobile HF Equipment

The next part of the presentation covered the selection of equipment for a Mobile HF Station. Safety and good usability are the paramount concerns here. I believe that a Transceiver should have the following attributes to be a good choice in Mobile HF applications:

  • It should have at least 100W output on the HF bands
  • It must have an effective Noise Blank and a good Noise Reduction system
  • It should have a removable control head to facilitate mounting of the radio’s controls and display where they can be easily seen without taking one’s eyes of the road

It is extremely important to consider safety in all things mobile HF. Safe, non-distracting mounting of controls is a top concern. One also needs to consider what could happen in a crash. Loosely mounted parts or anything that can get between a deploying air bag and the vehicle’s passengers are among some of the important safety concerns. One should also consider accessories that facilitate safe mobile operation. Automated antenna controllers and a voice recorder to capture contact details for later transcription in logs are some good items to consider.

Bonding And Choking

Bonding And Choking

I believe the bonding and the associated effect on noise levels and ground losses is perhaps the most important factor  in determining the performance of a mobile HF station. “If you can’t hear them, you can’t work them.” Proper bonding of the exhaust system, body parts and the engine’s ground are some of the key items in this area. You can read more about how we did this here. To give some idea of how important this area is, I was able to take the initial S9+ noise levels (with the radio’s preamp off) of my F-150 pickup truck prior to proper binding to an S3-4 level with the radio’s preamp on. This is a huge improvement and is a primary reason for the DX performance of our mobile HF station. Bonding also lowers the Ground Losses of the installation which improves the efficiency of the antenna system when transmitting as well – again a win-win. Proper bonding is not expensive but it does take some work. One must also be careful when drilling holes for the installation of ground straps that you do not accidentally drill into wiring harnesses, gas tanks, electronic boxes and other vehicle systems. Again, consult for more information on how to properly Bond your vehicle. If you use a screwdriver antenna, you must also properly choke your control leads to keep RF out of your vehicle and its electronics. Here’s some good information explaining how to do this.

Stage 1 Mobile HF Station

Stage 1 Mobile HF Station

I am a proponent of building a Mobile HF Station in stages from a simple one using to perhaps a more involved project later on. This allows the operator to have a lot of fun on the air with a reasonable initial amount of work and expense. The approach also provides the opportunity to see how the various steps outlined in the presentation contribute to improved performance. Our stage one installation consisted of a 100W transceiver and Hamstick antennas. You can read more about our Stage 1 installation here. The focus at this step includes proper bonding/noise control, safe installation of a suitable transceiver and simple Hamstick antennas. This stage gives you an inexpensive and effective, one band at a time, station on the 20m and higher HF bands. This type of installation is not difficult to do as is possible on most vehicles.

Stage 2 Mobile HF Station

Stage 2 Mobile HF Station

A Stage 2 installation would probably involve a multi-band remotely controlled antenna – typically a screwdriver antenna. You can read more about our Stage 2 installation here. It’s important to choose and efficient screwdriver antenna. You can read more about the choices and what to look for here. We used a Scorpion SA-680 Screwdriver Antenna and are very happy with it. This is a big antenna and you must carefully focus on a strong and secure mounting system to use it safely. Our Stage 2 station was QRV on all HF bands from 80m – 10m and utilized a screwdriver controller to automate the adjustment of the antenna when changing frequencies and bands. We use a 4′ rod and a Cap Hat to improve the efficiency of the antenna system as well. This is an important safety feature and should be strongly considered in any screwdriver antenna installation.

Stage 3 Mobile HF Station

Stage 3 Mobile HF Station

A Stage 3 Station is probably not for most folks due to the added complexity and cost but it does create a “work the world” Mobile HF Station and can open the door to effective operation on 160m from a Mobile Station. This step involves the installation of an Amplifier and may also include extension of the antenna system to operate on 160m. I would have to say that the upgrade to Stage 3 was as much work in our station as Stages 1 and 2 combined. It also brings a new set of important safety considerations due to the high current DC powering required by a mobile amplifier. You can read more about this Stage of our installation here.

Mobile HF In A Car

Mobile HF In A Car

It is also quite feasible to install a Mobile HF station in a car. The slide above shows Dave, N1RF’s installation of a Stage 2 setup in his Honda Accord. The mount is a custom-made unit done by a local fabricator. Also note the equipment mounting on the fold down rear seat of the vehicle. This installation uses and Icom IC-7100 and has produced some great DX contacts including on to the Philippines from New England on 20m using 100w.

Operating Mobile HF

Operating Mobile HF

Our presentation included some tips for operating a Mobile HF station. See the graphic above for details. I believe that even a well executed Stage 1 station coupled with good operating technique and some patience can yield a DXCC in many parts of the US and Europe. I was able to make many contacts to Europe and some to Australia, New Zealand, Hawaii and Alaska using our Stage one setup. If you progress through Stages 2 and 3, this gets easier. We have worked over 110 DXCCs from our Mobile HF Station and confirmed 100 in about 9 months with our Stage 3 setup. The Stage 3 setup has produced some of our most memorable QSO’s to date including my very first 75m phone contact ever to Japan and a contact with Ulleung Island, South Korea on the 40m band using SSB phone (these contacts were made from the East Coast of the USA).

Fun With Mobile HF - US Counties Tour

Fun With Mobile HF – US Counties Tour

There are lots of fun things that you can do with a well-built mobile HF station. I have worked many DX contacts from the mobile for example and some have netted as many as 75+ DXCC’s in a weekend. County Hunting and Tours to activate rarer US Counties are another popular activity for Mobile HF operators. You can read about one such County Hunting tour here on our Blog.

We have found building and operating a Mobile HF station to be a lot of fun! It’s almost like beginning our Amateur Radio experience all over again.

– Fred (AB1OC/M)