How to work 3B7C: Rigs and Operating Technique

What about your transceiver?

The answer is that most transceivers these days are more than capable of doing the job, and almost all elderly ones are too. The only feature you will need that you may not be using in your day-to-day ragchewing is split-frequency capability. 3B7C, like almost all DXpeditions, will operate split-frequency at all times in the early parts of the expedition, though may revert to co-channel working later, when the pile-ups diminish, for those without the capability. What is split-frequency operation, and why is it used?

Quite simply, DXpeditions transmit on one frequency and listen on a different frequency. For example they will transmit on 28.495MHz and listen between 28.500 and 28.520MHz. There are two reasons:

1. If the DXpedition station listens on the frequency on which it is transmitting, it will not be heard by those calling because of the pile-up on that frequency.

2. The DXpedition operator will be faced with a huge barrage of calls and will not be able to differentiate between them if they are all calling on the same frequency.

Experienced DXpeditioners will tune slowly up and down their listening band. Listen to the stations working the DXpedition and establish the operator’s tuning pattern. Work out where he is likely to be listening next and then call – bingo! Never, never transmit on the DXpedition’s transmitting frequency unless the DXpedition says “Listening this frequency”.

On CW, generally all you will need to do is set your receiver to the 3B7C frequency and then use XIT (transmitter-incremental tuning) to offset your transmitter by the necessary split (see your transceiver manual if you haven’t had occasion to do this before). Activating RIT (receiver incremental tuning) will also allow you to hear the calling stations, while leaving your main receive frequency on 3B7C.

RIT and XIT usually only work for splits of up to 10kHz, which may not be sufficient for SSB operation. In this case you need to bring your second VFO into operation. Set, say, the A VFO on the 3B7C frequency. Set the B VFO on the frequency where 3B7C is listening, and activate “Transmit on B, receive on A”. Again, your transceiver’s manual will explain how to do this.

When 3B7C responds to your call, the exchange will consist simply of an exchange of signal reports. Make sure the 3B7C operator also has your callsign correct. The reason for the short, contest-style exchange is simple – the expedition operators want to maximise the number of people who get a chance to work 3B7C, so contacts are kept as short as possible. Information such as QSL route, etc. have been announced in this magazine and elsewhere, and there will even be a log lookup facility on the 3B7C Web Page so you can be sure that you are in the log OK. If not, then do feel free to have a second attempt. If your contact is, indeed, OK, then please try to work 3B7C on other bands and modes.

So where on the bands will you find 3B7C? The plan is to focus initially on the frequencies listed below, subject to change for technical or operational reasons. In any case, the team is well aware that band plans in some countries, including the USA, restrict certain classes of operator to sub-sections of the band. This will not only be reflected in the range of listening frequencies used, but in transmitting frequencies as the DXpedition progresses. With widespread use of PacketCluster (via VHF/UHF and Internet) and the DX Summit Web pages, even if you don’t hear immediately, you should always be able to find out very easily where the expedition is currently operating.

Regarding the above frequencies, there may well be other DXpeditions active at the same time or interference on any of the pre-announced frequencies, so the team may decide to change transmitting frequencies to avoid confusion. With easy access to the Cluster system you should, in any case, be able to find out very easily the frequencies on which 3B7C is being worked at any given time.

Typically, a DXpedition SSB station transmitting on 21.295 MHz will listen up in the range of, say, 21.300 to 21.320 MHz. If 3B7C finds itself operating on the same transmit frequency as another DXpedition it will, for example, move down around 5kHz typically to 21.290 MHz and will then listen down say between 21.265 and 21.285 MHz so as to split the pile ups and avoid confusion.

Listen to the operator carefully. Each has been briefed to give the 3B7C callsign at least after every two QSOs and to announce the listening frequencies every five QSOs. Incidentally, will not work by numbers; believing that with good ears and equipment this is quite unnecessary.

There really isn’t the space here to discuss how to get started with the more specialist bands and modes, but the team does encourage readers to have a go. There have been many articles written about getting started on RTTY and PSK, which is straightforward using a personal computer and its built-in sound card. Follow the links on this website for help and advice and useful references.