Sunday, July 21, 2019
Why VHF/UHF SSB?
Many beginner amateurs start off with a VHF/UHF handheld FM transceiver (or more recently) one also featuring digital voice modes. Experiences with this shape their view of what VHF/UHF frequencies can do. That is a reliance on repeaters and local communications unless an internet link is involved. Later on they may get on the HF bands to work longer distances. Others may have started on HF, remained with this as their first interest and only got VHF for local FM contacts. People in both groups have missed out VHF/UHF SSB and the experience of their attributes.
These videos have been collated to indicate what is possible on 6m, 2m and (to a lesser extent) 70cm SSB. All involve contacts with low power and basic antennas. Yet the distances achieved often exceed that normally achieved on FM, even with repeaters.
Why is this so? The first thing is that per watt SSB is more efficient than FM. This is because of SSB's narrower bandwidth and the characteristics of FM which make it great when signals are strong but less readable when signals are weak.
Secondly (on average) SSB operators have better stations, antennas and equipment than average FM operators. It's not true in all cases but many FM operators only need to access repeaters and talk locally on simplex. A small improvement to antenna gain will often go unnoticed. Whereas SSB operators who work direct to each other, often over extended distances, will notice even small increases in gain. The combination of a taller mast and substituting a small beam for a vertical will increas your singnal by 10dB on a band like 2 metres. Another 10dB gain is possible by increasing power from (say) 30 to 300 watts. That's good but if you combine that with a distant station who likewise improves their antenna and output power by similar amounts then there's a massive improvement in signals between the two stations.
And I haven't even factored in other upgrades such as lower loss feedline, masthead preamplifiers, portable locations or modes even more efficient than SSB such as CW and the increasing family of digital modes used on VHF/UHF.
Facets of VHF/UHF SSB vary and can include DXing, contesting, local nets, satellite communication, experimentation, antenna work, aircraft enhancement, EME (moonbounce) and more. Activity is not always immediately apparent but if you listen and tune around long enough as well as familiarises yourself with local patterns you will find it.
These videos show what's possible with VHF and UHF SSB with low power and modest antennas. In all cases I'm running 5 watts or less. Antennas used have included small loops on 6m and, on 2m and 70cm, dipoles or small beams. In no case am I transmitting from great heights. Some contacts have been made pedestrian mobile. Typical ranges for this are 30 to 100km, with over 2000km occasionally possible on 6 metres during sporadic E openings.
6 metres pedestrian mobile
VHF/UHF Field Days (mostly 2m SSB)
2m SSB portable results in response to an alert that the band was open
Pedestrian mobile 2m and 70cm SSB
Equipment and antennas
I've used a Yaesu FT-817 as this suits my style of portable work. Larger 'All-in-one' HF/VHF/UHF transceivers typically include at least 6 and 2m SSB. Antennas vary greatly in size but even a small beam is enough to get you started.
Operating is quite different to both HF and VHF/UHF FM/repeaters.
If you were to turn on at a random time, the chances are that you will hear no one at all. In many areas there is activity but it's harder to find than on HF. It may be heavily based on nets and regular operating periods during the week. For example here in VK3 we have a 70cm SSB net on Monday evenings (7:30pm 432.310 MHz), a vertically polarised 2m SSB net on Tuesday evenings (7:30pm 144.310 MHz), a Wednesday evening 2m SSB horizontally polarised net (8:30pm 144.150 MHz), a Thursday evening 6m SSB net in Bendigo (9:00pm 52.250 MHz) and aircraft-enhancement activity on weekend mornings. That doesn't include other spontaneous activity. So you're pretty much guaranteed activity on most days if you're around at the right time.
To improve your chances, familiarise yourself with beacons, calling frequencies, local field days and nets including looking up club newsletters, joining social media groups and searching the web. And not to mention old-fashioned tuning around and asking people you work.
What have been your experiences with VHF/UHF SSB? Please leave your comments below.
PS: Enjoy these well-reviewed books on various amateur radio topics. They're available for under $US 5 each in electronic form. Or you can get them in paperback. Visit VK3YE Radio Books to find out more.
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