Top band DX-ing is real ham radio challenge. 160m is also referred as the "Gentleman's band"...
160 meters - DX-ing on the Edge...

Říjen 2007

Nice condx to JA...

13. října 2007 v 23:26 | Petr, OK1RP |  Band reports
Hello,
tonite I turned on my K2 around 20:50U and I am very surprised how the band is opened to JA's.
At 21:07U on 1817.5kHz I heard booming JL8GFB. Sigs came up 599+5dB and mni other JA's I copied on the band...JA3EMU, JM1GYQ and of course JH2FXK.
Also on frequency of Ken, G/W4DU working from Dover in UK on 1817.5 I heard few JA's as they are calling him but Ken was not able to cpy them. Well the band sounds tonite very noisy w/QRN but condx must be very well...
BTW: If You are looking for 4S7 on 160m then look for 4S7AB. Tonite working on1814.5kHz with solid signal over here. Kamal has not big gun setup but tonite his sigs comes thru very nice.
73, Petr OK1RP

Antennas inspiration - part I.

10. října 2007 v 18:38 | Petr, OK1RP |  Antennas
Hello all,
as I mentioned already I am still looking for an antenna which will fit to my fixed QTH. Unfortunatelly it is not easy as there I have pocket garden which is not suitable even for HF bands so the installation of some antenna for Topband is really challenging...
I tried a lot of different types as I am getting an ideas from the books, magazines, internet webs or from discussion with friends etc. but suddenly did not found right one.
Well if You have quite same situation and You are looking for some antenna which will fit to Your location then You can get an inspiration from articles which will comes step by step over here. I will share it (with permision of the owner or originator) althought it not helped to me as the situation is always different and it can help to You maybe.
160m band loaded vertical
First what You can try is the loaded vertical as described on the picture.
"Anything is better than nothing. Try for example this configuration when You have to use pocket size garden nor limited space for antennas"...saying about that antenna W0UCE who inspired me to test it.
This antenna has problem with the installation as it is a bit complex and lot of wires makes troubles specialy in the winter. Heavy frosted will need strong support and wire loading is extremely high.
Well I tested shortly and it resonated well in band -> I made few QSOs and sound that vertical has still good efficiency with low radiation angle valid for DXing.
Important is to spend time to grounding system which need to be as wide and good as possible. If the grounding system is bad You wasted money and time for building the vertical. It was reason why I decided to not use it longer and antenna went down.
160m band sloper system
The inspiration for that antenna comes again from W0UCE. Seems to be a bit complex again but the core idea is simple.
The main advantage is in single support only. As I said in my case there is only pocket size lot and even I had low pole for the support so the apex was during the test only 12m bended. I never had success with that antenna -> for sure because of low apex and not properly solved the feeding point.
...will continue
73, Petr OK1RP

Do You need ZL7 on 160m ?

7. října 2007 v 18:53 | Petr, OK1RP |  Band reports
Hello,
on 5th October started the operation of three Polish ham's from Chatham isl. (ZL7).
You can find them as ZL7/SP9PT, ZL7/SP5EAQ and ZL7/SP9BQJ. As promised SP9PT they should be QRV also on 160m band.
Their operation should be closed on 18th October so it is enough time for now to watch them if You need ZL7 on that band. QSL via their home calls.
...anybody hear them on Topband already ?
73, Petr OK1RP

Noise Cancelling Headphones - part II.

5. října 2007 v 11:00 | Petr, OK1RP |  Technical topics
Hi all,
as I promised in preview article about the noise cancelling headphones there are another informations about the different types and performances as it was published on some of web pages...
This article aims to help you buy those snazzy noise canceling headphones, by answering common questions, and offering a detailed review of the most popular headphones.
What is active noise cancelling?
Active noise canceling is the process of detecting an annoying low-frequency sound (like an engine hum) and producing a sound wave that is the complete opposite of that sound. When the annoying sound and its complete opposite meet, the annoying sound is reduced by 80% or more. The other type of noise canceling is called "passive" noise canceling which is nothing more than utilizing materials that simply dampen sounds. Foam ear plugs are a good example of passive noise reduction.
How much noise do they really eliminate?
Active noise canceling is the process of detecting an annoying low-frequency sound (like an engine hum) and producing a sound wave that is the complete opposite of that sound. When the annoying sound and its complete opposite meet, the annoying sound is reduced by 80% or more. The other type of noise canceling is called "passive" noise canceling which is nothing more than utilizing materials that simply dampen sounds. Foam ear plugs are a good example of passive noise reduction.
What is the difference between around-the-ear, on-the-ear or in-the ear type?
  • Around-the-ear headphones are typically a large padded oval that completely surrounds your ear. These are the largest sets, but often provide very good sound dampening.
  • On-the-ear headphones are typically oval or round speakers that don't cover your entire ear, but instead rest on your ear itself. These sets are a little smaller and are often more comfortable for sleeping.
  • In-the-ear headphones, also known as "ear buds", are headphones that rest in your actual ear canal. These are the smallest headphones to carry, but many find them uncomfortable when wearing them for long periods.

Headphone Testing Results

There was purchased 6 of the most popular noise canceling headphones on the market and rigorously tested them. It was lugged all 6 pairs with us on multiple airlines, multiple aircraft, and used them in multiple seating locations. In the end, was compared them on four criteria: Noise Canceling, Comfort, Size, and Price. The table below can be sorted by any column. Simply click a column header (i.e. Comfort) to re-sort the table.
Headphone ModelNoise CancelingComfortSizePrice
Bose QuietComfort 31st1st2nd6th
Bose QuietComfort 22nd3rd3rd5th
Sony NC503rd-Tie5th6th3rd
Sennheiser PXC 3003rd-Tie2nd1st2nd
Panasonic RP-HC3005th4th4th1st
Solitude 26th6th5th4th

Overall Ranking and Recommendations

For our overall ranking and recommendations, we used a weighting system of Noise Canceling (40%), Comfort (25%), Size (20%), and Price (15%).
Bose QC3
1st Place - Bose QuietComfort 3: Quite simply amazing. The Bose Engineers successfully created a smaller on-the-ear headset that offers better noise canceling than the previous generation. The build-quality is very high and the leather they use is incredibly soft. The only drawback, a minor one, is that the unit uses a proprietary rechargeable battery which makes an in-air battery change impossible (unless you buy an extra battery from Bose and remember to charge it too). The headset does not pass-through music when the battery is dead. When fully charged, the battery will last for 20 hours.
Sennheiser PXC 300
2nd Place - Sennheiser PXC 300: Our editors choice for combining good noise reduction with a very small case, light weight, and reasonable price. This on-the-ear headset folds down to almost half the size of all other units tested. This headset was also very comfortable for sleeping, again, due to its smaller size. There were only two drawbacks, first, the noise canceling electronics are in a separate corded unit that cannot be disconnected from the headset, and second, the noise canceling performance on extremely loud propeller planes was sub-par. The headset requires 2 x AAA batteries for noise canceling, and allows music to pass-through even when the batteries are dead.
Bose QC2
3rd Place - Bose QuietComfort 2: For the last few years, this set of around-the-ear headphones has been the gold standard in noise canceling, and in our tests was only beaten by its newer generation sibling. The oval shaped around-the-ear design was the most comfortable around-the-ear unit in our tests. While the case is a little bulkier than others, an iPod fits nicely in the center of the case between the headphones. With the next generation of these headphones on the scene, it might be a good idea to look for a bargain pair of these on eBay. The headset requires 1 x AAA battery but does not pass-through music when the battery is dead.
Panasonic RP-HC300
4th Place - Panasonic RP-HC300: These were the cheapest set of headphones in our test and they offered adequate noise canceling. The design of these around-the-ear headphones is comfortable and they are very light yet don't feel cheap. There is a slight echo in the headset probably due the use of less dampening material. The cord offers a unique twist-lock feature to keep from becoming accidentally unplugged. The headset requires 1 x AAA battery but does not pass-through music when the battery is dead.
Sony NC50
5th Place - Sony NC50: These were the largest and heaviest headphones in our test, but the extra size certainly produced quality noise-canceling. The heaviness of these around-the-ear headphones became a little uncomfortable during long periods of time, and the ear cups weren't quite as comfortable as the Bose 2 pair. These headsets do offer a "monitor" button that when pressed allows you to briefly hear noise from the outside world. This feature allows you to keep your headset on when the flight attendant or your seatmate asks you a question. The headset requires 1 x AAA battery for noise canceling, and allows music to pass-through even when the battery is dead.
Solitude 2
6th Place - Solitude 2: We were excited to have a lesser-known competitor in our review, especially one that claimed to beat the Bose headset in head-to-head testing. That initial excitement however quickly turned to utter disappointment for these around-the-ear headphones. The plastic feels cheap, the square headband shape is very uncomfortable, and the noise canceling was the worst of the bunch. The only positive we could find was that the case has a molded center spot that was designed to hold an iPod. The headset requires 2 x AAA batteries for noise canceling, and allows music to pass-through even when the batteries are dead.
73, Petr OK1RP
(Orig. material published on http://www.seatguru.com)

Noise Cancelling Headphones - part I.

5. října 2007 v 10:12 | Petr, OK1RP |  Technical topics
THE NEW WEAPON: N-C HEADPHONES

by Roger Western, G3SXW (Republished from November 2005 CDXC Diges, bi-monthly journal of the Chiltern DX Club.)
Published in FOCUS 66 - Spring 2006 (First Class C.W. Operators' Club Magazine) and also on Martin's web pages www.ok1rr.com on Mar 14th 2006...

Maybe I am the last person on the planet to experience this new piece of technology. If so, my apologies - please ignore what is to follow. But I get the impression that few DXers have tried noise-cancelling (N-C) headphones on the air. Here is my story so far. I was impressed when my friend Ian, G3WVG, let me listen to his £60 headphones, a while ago, on an aeroplane. The effect was dramatic. It killed a large proportion of the in-flight noise. But, ahem, that seemed rather a large sum to pay for this pleasure. However, I could see that this might help to reduce fatigue and to increase listening-pleasure on long-haul flights. Then I saw an advertisement in RadCom for the Fujikon noisecancelling stereo headphones at less than £20. Now you're talking! So I bought them. See RadCom, October 2005, page 98, bottomleft, Waters & Stanton. You can buy the Fujikon NC-2 for £18.95 or the folding design NC-4 for £19.95. I splashed out the extra one pound.

Physical
In practice, these are good stereo audio headphones like any other. They work fine and are comfortable. They are 32 ohm with maximum power output of 60 mW PMPO (whatever that might mean). They have sensitivity of 116 dB (off) and 122 dB (on). It comes with a long cord (just over five feet) and a 3.5 mm stereo plug; a twin-plug adaptor is also provided. The important bit is that they noise-cancel at 15 dB or greater, at 300 Hz. This means in practice that low-frequency ambient noises are cancelled. Normal audio received down the headphone line is not suppressed. This means that the masking of desired low-frequency audio is removed. The type of ambient noises that are best suppressed are constant engine noises. This includes hum and burble from aircraft noise and from fans, eg amplifiers, computers, airconditioners. These are the most noticeable but even voices (live or TV/radio) are suppressed.

The foldable-version has elbow-joints, just above the two ear-pieces. This allows the head-band to be folded back down between the ear-pieces and to fit nicely into the smart draw-string carrying-bag which is provided. That bag nicely carries the twin-plug adaptor and your spare AAA batteries.
In-Flight
The effect is quite dramatic. Suddenly you can hear the movie sound-track clearly. It is like chalk and cheese. You know that feeling of frustration when you are trying to listen to a movie or your favourite jazz soundtrack and you have to struggle. Those days are gone.

I have suffered for some while with tinnitus (the hissing type), so I perhaps pay attention to hearing issues more than most people. I am convinced that the world is becoming a noisier place and that we are all conditioned to accept this as the norm. A result is degradation of pleasure but when flying, for example, I wonder the extent to which it also adds to fatigue. You get home from a long flight feeling exhausted, yet you have just been sat there doing nothing all day. I can honestly say that getting home recently from two back-to-back eleven-hour flights while using these N-C headphones I actually felt human.
On-Air
Anyone who has operated the bands with the benefit of a beverage receiving-antenna will know the magic that they can perform. Suddenly you can copy a signal which was previously below the noise. This only works when the signal to noise ratio is marginal - you can just about hear the signal but cannot copy it. Switch in the beverage and the S-N ratio improves by just a few dB, enough to copy the signal. At 5U5Z last November our transmit signal was greatly enhanced by use of the tall Titanex vertical, but without the beverage we would have made hardly any contacts because almost all signals were below the noise.

Forget installing beverages - use N-C headphones. I am exaggerating of course. It would be best to use both, but the affect is similar. Those marginal signals are so frustrating; you can hear them calling but they're not quite loud enough to copy. Switch on the N-C headphones and suddenly those low-frequency ambient noises are killed and you can copy him. This occurs rather infrequently.

Most signals can be copied or else cannot be heard at all, but for those few signals which are right on the margin it's like a piece of wonderful magic. Beyond making signals copyable, there is also a perceived increase in audio-quality. It actually feels more complete and enjoyable and even your CW sidetone sounds more crisp (and louder) when it is not being masked by those low-frequency ambient-noises.
Convinced
I am convinced. This is the new secret weapon for any DXer or contester. Go buy them (no, I am not on commission). It is the best new operating-aid since they invented the iambic-keyer or the computer-logger. Downside? Well, only one, these N-C headphones work with one AAA battery that only last about 24 hours. So, firstly, just get into the habit when slipping them off the head of flicking the 'off' switch. For one-off longhaul flights (rather infrequent for most people) this is not a problem- just load a new battery before travelling. For a contester, not a problem, maybe you need to put in one new battery to get you through a weekend. For regular use at home, maybe you leave them switched off until you hear that marginal signal which needs the N-C help. When the battery starts to fade you notice that the 'On' red LED fades. Then when the battery has died the LED does not light at all, the NC effect stops, but normal audio continues as usual. Finally, at the complete death of the battery you hear popping-noises whenever they are switched to 'on' position.

As you might begin to surmise, I am rather impressed. The cost/benefit ratio could seldom be better.
From Bruce, AA4Z (from the FCG Reflector)
Noise Cancelling Stereo headphones were easy to find in the Clearwater, Florida, USA area. The local CVS store had them displayed along side personal DVD players. They were priced at $14.95 but were on special offer for $9.95!

First of all, they are a reasonable set of headphones for $9.95. In series with the cord there is a control with a volume control, a mute switch, and an on/off switch for the noise cancelling feature. They require one AAA battery, not included. The specification states 15 dB of background noise reduction at 300 Hz and 5 dB at 1200 Hz. I do not have a calibrated ear, but they did a good job of dropping down the TV (and the XYL). They are padded and reasonably comfortable. Even without the noise cancelling feature, they are as good or better than any cheap set I have found from Radio Shack.
From Chris, G4BUE
Just after reading Roger's article in the CDXC Digest, I saw a pair of the Fujikon folding noise-cancelling stereo headphones on eBay. After successfully bidding for them, I found them to be exactly as Roger has described.

One of my pleasures is trying to work weak DX signals on the LF bands and the NC headphones have proved to be the best aid since I put up my first four-square on 40 metres! They are very bit as Roger described. Like all new things, I am now wondering how I managed so long without them!

I forgot to take them with me when we went to Florida in January, but soon after we arrived there I walked into the local OfficeMax store in Sebring with N4TO and what did we see? N-C headphones on special offer for $25 reduced from $50. We both bought a pair. They are Phillips SBC HN050 and hang around the back of your neck (as opposed to going over your head) which I find very comfortable. They have an impedance of 45 ohms, a frequency response of 40-20000 Hz and a sensitivity of 102 dB/mW, but the noise cancelling figures are not given. They come with a five feet cord which includes an in-line 'on+off' switch designed to clip on your lapel for easy access, and the same two-way adapter for using with aircraft audio systems.

They work well but are not as good as the Fujikon headphones. They are as good at what we primarily want them to do, to help us to hear weak signals buried in the noise better, but they are not nearly as good at cutting out background noises, which would be very important if you intend using them in a noisy environment, such as an aircraft to listen to the in-flight audio.

Thanks Roger for bringing the advantage of using N-C headphones to our attention.
As its very interesting task in case of cancelling the noise specialy on Topband I am looking for solution also for myself. As the prices are quite different and the quality may vary I will try to put over there more informations step by step as I will getting them...
73, Petr OK1RP