Let's imagine you are a run operator in a multi operator team trying to win a popular DX CW contest. Let's assume you are on 20 m, the frequency is crystal clear, propagation is wide open to Europe and the contest just started. Someone just spotted you on the DX cluster. It's easy to imagine what's going to happen: a pileup will grow instantly.
The pileup will be handled just right by a very good operator and the stations will be aligned then worked one by one. If the running operator is not showing any slowness in his rhythm and the rate is going up, that's definitely an indication that the traffic is as efficient as it can be. Or maybe not...

The fact is that the operator running the wide open frequency is not aware about all stations calling him. There are so many "little-pistol" stations out there hoping to make a contact. The propagation may be open for a short period of time, the contest is limited to 48 hours so a good idea would be to work the stations right away. But the weak signals are not always heard as there are much stronger stations in a pretty good sized pileup. A DX operator during a DX activity would listen 1...5 kHz up to give to everyone a chance and he would listen careful for QRP and mobile guys, but the contest is something different, split is not possible and the pileup must be handled on a narrow band. Frustrated, many low power or/and simple dipole stations would leave the pileup after many attempts to be remarked. The contest strategy says that those stations would come back later anyway, maybe the next day when the pileup will be much easier to break. However there are many stations entering just a few hours in the contest, for fun. There are also significant variations in propagation so the next chance to work that station may never occur again. And there are of course many other circumstances when a new contact will not be possible again. Conclusion? The running operator should not allow any station to leave his frequency, every call sign counts and it must enter in his log.

Let's see how the pileup operator can get some help from the team (this could be a method for multi-operator categories only). Normally the S&P radio on that band would scan up and down looking for possible multipliers and points. That's very good, but the running station needs help on *his* frequency. The only solution is to have the other operator (one or more) listening to the same QRG with the same antenna collecting other call signs from the pileup. If the secondary pileup operator will get a different call and if this call is somehow submitted to the main operator, there is time saved: the station will not ask QRZ but it will send the report for another station, like that was on a list. The rate will be dramatically increased, the station will gain additional respect from the crowd and the multi-op team will act efficiently.

Here is a possible solution. Please see the diagram. Basically all radios (receivers) are listening on the same frequency, maybe plus/minus a dozen Hz. The RF antenna signal is distributed through the "Pileup killer box". When the running station is transmitting the PTT signal would command the box to switch off the RF signal for each AUX radio, not to burn the RF input circuitry. When the running station is listening to the pileup all the other radios (two in this diagram but they can be more or less) are able to listen to the pileup. The radios may use narrow CW filters and listen off the central frequency (up and down) looking for weak signals. When one is copied it is reported to the main running operator via a chat box (often included as a standard tool in contest log packages). The running station would listen the pileup with a wider filter and the strongest station will be copied. Once the contest RST/report is sent to that station the chat window may show 1 or 2 different call signs, entered by the other guys. After the standard "TU" the running operator will call immediately and send the contest report for the station(s) listed in his chat box. Once all stations listed are worked, a QRZ may be sent to let the pileup to explode again. The crowd would think that a super-operator is in charge! In addition many small stations will soon realize that they may transmit a little bit off the central frequency, to be easier copied since apparently the operator is not using a very narrow filter. In turn that would actually give to radios 1 and 2 a better chance to copy them.

In this diagram the key element is the "Pileup killer box". This is a very simple combination of coax cables and relays controlled by the PTT signal. Extra caution must be considered to avoid any situations when the RF power (as much as 100 W) would be applied directly to the AUX radios. The design must assume that the DC voltage (required to supply the relays current) may switch off at any time, accidentally. In this case, with no DC current the box would have the out connectors grounded and isolated from RF.

Another important piece is the chat application. The built-in feature existing in any multi operator contest logger is good enough. For example "Talk to another station" (CTRL/E) in N1MM log. Since the only station that is logging the contacts is the main run position, the AUX operators should not necessarily utilize contesting software only to chat to the main station. Any conference/chat program is suitable, including the well known instant messengers (internet connection is required in this case).

It's possible that some multi operator stations are working pileups in this manner already, but I've never seen it yet anywhere for real. However I listened this summer the traffic made by DA0HQ in IARU, it was amazing. The CW run operator was working lists of call signs (2-4). Where were they came from? I think from other radios listening that frequency.

Any questions or comments can be sent to my email address.

73s de Chip N2YO
n2yo [at] n2yo.com 
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