An Introduction to low VHF Skip.
Sitting on a Sunny March afternoon two scanning radios on my desk are tumbling through a hundred good reasons for listening to Low VHF. A Fire dispatcher in Massachusetts is checking his communications system with neighbouring rural counties. He un-keys his mike and is quickly replaced by a Turkish Police officer who although unintelligible to my English speaking brain is clearly getting more and more irate by the second!. I turn the main tuning knob and two Russian women are having a phone conversation- if only they knew!, More numbers spin and a traditional musician in West Africa is playing a long mesmerising dirge, and then there’s always the evening to look forward to, I wonder will California come in today…….How the hell far is it to California?.

Describing this aspect of the radio hobby as “ Utility Reception” does not  I’m afraid do the traffic received much justice!. It’s hard to say why you should check out Low VHF, but here are a few pointers which I hope will help you on your way to one of those sunny afternoons when being into radio is just about as much fun as is good for you!.

What is Low VHF Skip/ DX?

DX- ing at Low VHF  frequencies is the hobby of searching out distant radio signals between 30 and 87.5 megahertz. Low vhf occupies the part of the radio spectrum between the top of Short Wave and the bottom of the VHF- FM broadcast band. Because of this it displays some of the characteristics of both HF ( High Frequency) and VHF ( Very High frequency), this provides great opportunity for long distance reception by DX-ers.

What can be heard?.

Depending on prevailing atmospheric conditions signals can be heard  distances anywhere between 500 miles and literally the other side of the globe. When things are working well a wide variety of communications can be monitored, including military and emergency traffic, phone systems, business and paging transmissions and much more. Between 45 and 63 mhz some foreign TV vision and sound broadcasts can be received. While during the summer here in Europe some East European FM radio stations can be heard between 66 and 74 mhz in the old Eastern Bloc OIRT FM band. Broadcast links between studios and transmitter sites also often use Low VHF.

What kind of radio do I need?

Any wideband receiver covering 30- 87.5 mhz will bring you signals, some however work better than others. Communications receivers work very well but are costly, while scanning radios provide a good compromise. They also have the added benefits of fast scanning and search rates. This means you will be able to search through vast swathes of silent frequencies to find the active ones relatively quickly.

Many scanners produced for the British market have in the past not covered all of Low VHF, instead their coverage has started around 68 mhz. If you are thinking of buying a radio to get into Low VHF reception make sure that it covers the right frequencies!. Hearing very distant signals at higher VHF and UHF frequencies is extremely rare so think Low VHF!.

When choosing a radio try and find one with good blocking against overloading and spurious signals. Check out the specifications and look for image rejection figures- the higher the number the better. Above 50 db is good. You want a radio which will be capable of handling a decent sized antenna without filling Low VHF with unwanted ghost signals from Short Wave- covering all those nice dx signals you want to hear. Base scanners are designed to work with base antennae and are usually a little better in this regard. A good choice is the old Realistic PRO 2006 base scanner, these are sometimes found on ebay at affordable prices. You can plug a monster antenna into this radio and get away with it!

What kind of Antenna do I need?.

A simple wire fed to your scanner or receiver 3.5 metres long I have found works very well for Low VHF reception. Mount this horizontal at a slope of about 30 degrees. Simple antennas such as dipoles and quarter wave ground plane also work quite well. CB antennas are also quite good. Check out my antennas page here for a few simple designs. Experimenting is the key to better reception so don’t be afraid to try different things- just avoid overhead power lines in doing so!- there is nothing better than coming up with something homebuilt cheap and simple which brings in signals a little better. Use your web browser and check out antenna project sites. Forget about bought scanning antennas, these usually perform at best mediocre on these frequencies and you will come up with something much better yourself and at less cost.
How does Low VHF Skip work and when should I look for signals?

It is important to remember that at VHF frequencies, unlike HF (3-30mhz) the distance covered by signals is relatively short. Often you will hear this referred to as line of sight pick up. So the horizon or shortly beyond it, from your location, is what you are likely under normal conditions to hear.

This said there are some often-occurring anomalies which turn Low VHF into a very interesting place to spend some time. There are modes of propagation which can turn that line of sight rule on its head, and leave you asking, as one friend of mine did on hearing American Fire Brigades- “How the hell is this happening”!. The main ones are on the following page- read on!.