Battling Noise - Theirs, Not Yours

You can't work 'em if they can't hear you.

This turns the old cliche on its head yet it is as true as its original. This can be particularly true on the lowest bands where the ambient noise is high and our antennas are often less than full size. Even for those of us with QRO and good antennas on 80 and 160 meters noise is a challenge.

I can control noise on my end and I am. Right now I am in the midst of installing a reversible Beverage antenna that, if it works as it should, will be replicated and then the three antennas brought together to a remote switch. That will give me 5 compass directions and more will be added later. I may add another receive antenna for the second operating position (multi-op contesting).

What I can't control is the other station's noise. My only weapons are power, antenna efficiency, antenna gain and good timing so that I operate when there is propagation enhancement. The latter includes sunrise (theirs or mine) and difficult to predict periods of low absorption. Beyond that I can only hope that the other station has a low noise receive antenna and that their local noise environment permits them to copy me.

Which brings me to the impetus for writing this article now: 9J2LA.

Those who have been calling them on the low bands are well aware that they are not hearing well. The local man-made noise has severely their ability to copy callers. It is particularly dire on 160 meters. Despite their many attempts to lessen the problem with directional receive antennas working them continued to be a challenge.

They are to be commended for their efforts to ameliorate the problem and to persist nightly with making the attempt to work others on top band. Listening through strong QRN is very fatiguing and not much fun. I suspect quite a few readers who are urban dwellers can commiserate.

I tried and failed to work them on top band on a few nights. Few in North America were being heard and from the size of the pile up on this end many, like me, wanted a top band QSO with Zambia. I stopped trying if their signal was of average strength since I knew I wouldn't be heard. I did work them on 80 meters and even there they had trouble copying my kilowatt and 3-element vertical yagi.

After coming home from a pizza night with fellow QRP'ers I turned on the rig and heard 9J2LA stronger than ever. I decided to give it another try even though, again, few were getting through. But first I listened. My objective was to better understand their operating style and to see what the successful callers were doing. Too many hams jump in too fast and fail to survey the field and develop a strategy. The investment of a few minutes of observation can pay dividends.

The first thing I noticed was that of the few stations they were able to copy all but a couple were Europeans. Luckily they were strong enough that I could copy 9J2LA on the northeast Beverage and copy most of the Europeans calling and working them. There was little VFO movement on their part between QSOs so the callers clustered in a spectrum +1 kHz to +2.2 kHz up.

The downside was the QRM from overlapping signals. Many in the pile up picked up on the pattern and set their transmit frequencies accordingly. It is likely that the QRM and their QRN were of similar strength which would make it difficult to focus on one signal. That many stations continued to call whether or not they were being called (or having a call sign containing the partial call being sent) didn't help. Perhaps they should have QSY'd more between QSOs to avoid the clustering of callers.

Then they worked a US station. That signal was +2.1 kHz where I could hear no other signals close by. Clearly the operator did finally spin the VFO a little higher. Of course several North Americans then called a little up or down from that frequency. However the next QSO was from the pile up at +1.75 kHz and everyone moved back to where they were before.

The diagram gives a rough idea of what I was hearing. Most callers were between +1.1 kHz and +1.9 kHz. Signals overlapped such that no one of them was alone inside a 100 Hz filter. Callers were either not listening on their transmit frequency to see if it was clear or they were big guns who saw no need believing they could out-muscle the competition.

A few callers straddled the +1 kHz minimum offset hoping to be heard eventually. That is not a bad strategy and I've used it to good effect many times. In this case the pattern didn't fit so it didn't work for them.

Numerous stations zero beat the last successful caller and called there, sometimes while the QSO was still in progress. There's nothing like a DX pile up to bring out the worst in amateur radio operators. I won't mention call signs other than to note at least one is on the DXCC Honor Roll and some are regular denizens of "the Gentleman's Band". A few others are well known DXers and contesters. Trust me, people are listening and will remember.

Predicting where the DX will listen next is an art and a science. I decided to only call where I was alone within a 100 Hz bandwidth (at least 50 Hz on either side of my transmit frequency). In an earlier article I dubbed this technique "calling in the hole". My reasoning was that with their high noise level two or more signals in their receiver pass band could not be disentangled except by a very rare and talented operator or unless one of them was exceptionally strong. Odds were against both.

By listening I knew he was focussing in a narrow range between +1.5 kHz and +1.9 kHz with occasional forays beyond +2.0 kHz. So I transmitted around +2 kHz, moving up or down as necessary to avoid other callers. That kept me out of the QRM but close enough that I stood a good chance of being stumbled upon. A few minutes later I heard the welcome sound of "VE3?".

At this point you might think I'd bang on the keyer button to send my call a couple of times. When SNR is very low this is usually a poor approach. From long experience I know that copying "VE3" is rarely a problem since it's a common prefix and it has a distinctive swing on CW. The greater challenge is getting the "VN" suffix across successfully!

I resorted to the paddles to alter the character cadence. I kept my speed where it was, set to closely match their speed. Several unsuccessful callers persisted in sending at a significantly higher speed. The operator at 9J2LA would keep missing dits or confusing the prefix and suffix since they ran together when the call sign was sent two or more times in quick success.

Working DX is not a high speed CW contest or brag-fest so think very carefully. When the DX station slows down it is for a reason. The reason may be that that's the speed they're comfortable with. In this case it was almost certainly because they needed longer dits and dahs for their ears to integrate the signals across the rapid and repetitious man-made impulse noise.

I used the paddles to send VE3 with normal character spacing and then send V and N with larger spaces around each character. I put a larger pause before repeating my call sign in the same fashion.

Either I was lucky or my technique worked since my full call sign was repeated back to me along with a signal report. A repeated 599 in reply and I was in the log. Further luck was no one jumping onto my frequency during the brief QSO. With a clear frequency and carefully articulated characters the QSO was not drawn out like many others so impatience had little opportunity to overrule manners and sense.

The same technique can be useful in everyday DXing for non-rare stations. Indeed it also works in contests to work many of the slower speed casual participants. Sending fast and carelessly slows you down since you won't be copied the first time, and maybe not the second or third time if you persist.

Before you call give some thought to the other station's operating conditions and adjust your technique accordingly. Sitting in front of a radio all night long trying to pull eager callers out of loud and grating noise is difficult. Don't make it any more difficult for them. In the end you, too, will benefit.