Finding VHF Weak Signal Activity

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

VHF DXing is different from HF in several important ways. One of the most obvious is propagation. At VHF we don’t have propagation around the globe and what we do have tends to come and go on a whim. Everyday troposcatter conditions allow the small station to work 150 to 300 miles and big stations up to 500 miles. Beyond those limits we are faced with waiting for opportunities. Another factor is antenna directivity. Most two meter and up stations use multi-element yagi antennas which are very directional. Beyond “local” range of 150 miles or so, it is usually necessary for both stations to have their antennas pointed at each other. Sometimes this happens by coincidence but often it doesn’t. Many VHF and up contacts are the result of scheduled attempts.

So how do we find each other and make the most of propagation opportunities? In the old days it was HF and the telephone. There were widely known meeting places on the HF bands where VHF activity could be coordinated. For example, during every major meteor shower, 3.818 MHz on the 80 meter band was a hot bed of activity. Many people wanting to find a station to “run” with on VHF would put out a call there and see who responded, or reply to another station who announced his availability there. 14.345 MHz was widely used for scheduling and discussing all types of VHF weak signal activity in Europe, and was used for the weekend EME nets where schedules were made worldwide. Often, avid VHF operators would call each other on the telephone to arrange a meteor scatter schedule or to try an impromptu contact during a tropo, aurora, or sporadic E opening. We also had something called activity nights. Monday evening everyone got on 2 meters and made noise on the calling frequency, 144.200; Tuesday it was 222 MHz, Wednesday 432 MHz, and so on.

Today, the telephone and HF are still used, but to a much lesser extent. Email lists or groups (“reflectors”), social media pages and groups, and internet chat sites have become the primary means of coordinating VHF activity. There are general forums and specific ones aimed at various aspects of VHF+ operating: digital modes, non digital modes, meteor scatter, contesting, EME, etc.

Not everyone has time to keep up with half a dozen active email groups, and most beginners aren’t going to be doing EME or meteor scatter right off the bat. I usually recommend ON4KST Chat as a starting point for those wanting to explore what is out there. It is easy to register and you only log in when you want to. All you need is a web browser. ON4KST has chat pages for 6 meters, 2 meters and up, microwave, EME, and low bands (160, 80 meters). People there are very friendly and willing to help newcomers to the game. The 144/432 MHz Region 2 chat page, for example, is used by North American stations wanting to coordinate activity or discuss topics relevant to DXing on 2 meters and 70 centimeters. This morning I checked in there and found W3BFC and KA1ZE/3 wanting to try working me on 2 meter CW. Via the chat, we picked a frequency and discussed any relevant particulars about who was going to transmit on 2 meters when (such as me transmitting during even minutes and the other guy during odd minutes). Six digit grid squares are listed on the chat; clicking on one causes the server to tell you the distance (in kilometers) and beam heading, so we knew where to point our antennas for the attempt.

Not everyone is comfortable with these tools, but I find them to be a great resource in the modern age. I am always interested in “testing the limits” to see how far I can get on VHF. Arranging QSO attempts in the various forums available allows me greater opportunity to maximize both opportunities and success. For me, this greatly increases the “fun factor”. Only the means is new. VHF and up contact attempts have been arranged and coordinated by other means since the early days.

A few words about etiquette may be in order. It is fine to set up a time, frequency, and calling sequence for a VHF or UHF QSO by means of these forums. It is OK to change those details during a QSO attempt via the chat room; for example, asking the other station to change frequency if you have QRM. However, exchanging details of an ongoing QSO attempt on the chat invalidates the contact – or at least it should. For example, if I am attempting to work VE7BQH on 2 meters and I say to him on the chat site “I am sending you a 559 report”, I have just invalidated the contact. The signal report should be part of the amateur radio QSO, sent and copied over the air, not via the chat room! As with any other aspect of the hobby, you will see some people violating this long standing ethic. In the end, we are each responsible for our own ethics. Those who take the easy road are only cheating themselves. Again, it is the QSO details (signal report, “rogers” or other acknowledgement) which should not be given by any means other than over the air on the band you are trying to make a contact on.

You can find the ON4KST chat site by starting here:

I could make a case for the chat being the only tool necessary to know when the bands are open. If there is unusual propagation, chances are the avid VHF operators logged in there know about it and are all abuzz making the most of it! However, I still find VHF propagation tools useful. For example, the APRS-derived propagation map found at is a good way to spot potential 2 meter openings. It works well for tropo and sporadic E, but not for aurora (because auroral propagated signals are too distorted for APRS to decode). It is not the “last word” on whether the band is open. False positives can occur from meteors which are long gone by the time the map updates. Lack of APRS stations in specific areas can sometimes lead to the map not showing much when in fact some path may be open. Nevertheless, I find it quite useful. (Note: This map is supposed to automatically update every few minutes, but it often stops on all of my computers and browsers if I leave it open for a while; I click the refresh button every so often as a reality check to see if it has gotten stuck.)

Another (this one from the shameless plug department) is Aurora Sentry at This takes a little more experience to navigate and interpret, but has been my tool for spotting VHF aurora openings since 1997. Sadly, as of this writing it is in need of a re-work. Data sources come and go.

Whatever your preference, the more activity we get on the VHF bands the better. It’s always a good idea to put out a CQ on the calling frequencies from time to time, but non-VHF and non-amateur radio means of arranging VHF QSO attempts can definitely add to your success.

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