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...

Listopad 2007

TT Orion 565 on 160m & optimal setting - part I. by W4ZV

22. listopadu 2007 v 14:40 | Petr, OK1RP |  Operation topics
Hi all,
today I would like to start to talk about an operation practice a bit.
As I have chance to using TT Orion 565 tcvr on Topband also I found that there is big room to play with setting of that radio during an operation.
Some TT Orion 565 newbies (566 also) have troubles to set up their new toy correctly. However, any setting is a very subjective matter I will try to gather as many informations and settings as possible from most experienced DX performers and low band DX-ers to be able to get an idea how it works and how to make own setting.
Orion's AGC Controls
Orion has four sets of AGC settings: SLOW, MED, FAST and PROG. Each set is independently adjustable with PROG providing the widest range of adjustment.
Within RX menu there are three AGC settings (with separate values for each of the sets):
* AGC HANG time,
* AGC DECAY rate,
* AGC THRESHOLD level.
Here are the AGC settings found worked best for Bill, W4ZV:
(Originally published on Topband mailing list)
At night I was listening to YI9ZF on 80 while waiting for him to move to 160.    
He was right at my noise floor and was QRV for quite awhile before 0200.     
It was an excellent chance to play with Orion's AGC settings, and also to     
experiment with K6STI's DSP Blaster on Orion's audio output.     
         
Threshold : 95 uV       
Hang : 0.63       
Decay : 20 dB/S 
Using these, I could take Kas from about 339 to 449, and I seemed to     
be hearing better than most.  At times he dropped below my noise floor to the      
point that I thought he had gone QRT.  Then he would again rise above the noise and be OK copy.     
I was frankly astounded at what DSP Blaster would do! It was not only helpful for finding Kas' signal     
using the waterfall display, but made Q4 copy into solid Q5 copy.  The Coherent CW feature splits the     
signal into in-phase and out-of-phase components, and when you listen to this with stereo headphones,     
it almost makes the signal sound like it "jumps" out of the noise, even though it is only a theoretical  
and measured 3 dB difference.  I saved both my settings for Orion and DSP Blaster so I can experiment more     
with this in the future.     
I got everything set up on 160 after Kas QRT on 80, but he did not show up on 160 immediately. Both     
RA6AX and A45XR had decent signals and A45XR was peaking 569 at 0229 near his sunrise.  He runs     
a kW to a vertical but with just a few radials, so I expected Kas' 100 watts to a 20m high inverted-vee     
would be much weaker.  I was amazed to hear Kas on 1837 at 0230 CQ-ing with a 569 signal!      
No DSP or fiddling to copy him 100%, although I had left Orion's settings as noted above.  I worked him     
for #311 on Topband and listened to him for the next 1.5 hours until he QRT at his sunrise just before     
0400. Kas peaked 579 so he was even stronger than A45XR was at his sunrise! The AGC settings were     
quite comfortable to use and I could copy most of the EU and Russian stations Kas was working     
(UN7AM was 579!), and even many that he could not copy...I felt like I was VE1ZZ!  The only major     
problem was when some strong NA stations would call zero-beat and of course that took the AGC awhile     
to settle down afterwards.  I believe it would be possible to use similar AGC settings in a contest  
especially if you didn't have extremely strong stations inside Orion's passband.  I may give this a try if  
I decide to do ARRL DX CW on 160.     
Again thanks to Sinisa for causing me to play with the Hang and     
Decay settings.  I had discovered the effect of Threshold myself but     
probably would not have tried such high settings for Hang if he had     
not made those posts.  I've now had Orion nearly 6 months and am     
continuing to learn new things about how to use it properly!  I also     
continue to learn more about K6STI's DSP Blaster which is a fantastic     
program IMHO.     
Here is what Bill, W4ZV wrote to DL6FBL regarding the setting the AGC of the Orion 565 in the contest):
"I can say with certainty that Orion's default AGC Threshold settings are far too sensitive for 160. Threshold is set for 3 uV as default, and the lowest I ever had it in the CQ 160 was probably 30 uV, and sometimes higher. You can easily observe this by tuning to a quiet part of the band and adjusting Threshold to the maximum 192 uV. It will become very quiet (unless there is extremely high storm QRN) at 192 uV. You then adjust it down until the background noise is an acceptable level. [...] The AGC is the most different aspect of Orion and many guys have made the same mistake. [...] Orion really takes a little time to understand. [...] The manual is also at fault for recommending AGC settings for weak signals that are far too low for 160."
73, Bill W4ZV
Well, it is the recommendation by Bill, W4ZV. In the next article I will post the setting from European DX performers to compare it.
73, Petr OK1RP
...-.-

Noise Cancelling Headphones - part IV.

20. listopadu 2007 v 19:23 | Petr, OK1RP |  Technical topics
Noise - Canceling Headphones -> How it work ?
I received many emails regarding the N-C headphones where You asking me to explain how it works...so few words about the basic principles You can find below.
Silence isn't golden anymore. Really, in this world of booming car stereos, telemarketers, and the exact same music playing in every store and office, silence is worth much, much more than gold. If only you could make the din disappear. One small step toward personal tranquility is putting on a pair of headphones. Regrettably, ordinary audio headphones don't really give you the quiet you're looking for; all they can do is cover up outside noise with the music or radio station of your choice. There are also earplugs and noise-reducing earmuffs available, but these can be unsightly or uncomfortable. Fortunately, technology has come to the rescue. There are a number of noise-canceling headphones now on the market. Sony's MDR-NC20 headphones are a $179.99 option (http://www.sonystyle.com), while Aiwa's HP-CN6 headphones aim for more casual users at a price of $59.99 (http://www.us.aiwa.com).
So what are noise-canceling headphones, exactly? We talked to a engineer at Bose about its high-end QuietComfort 2 headphones ($299;http://www.bose.com), shown here in the main diagram. Read on to find out why they have microphones inside their ear cups and how they can produce near-silence with speakers.
Antisound?
It may sound strange, but headphones like these have to make noise in order to silence other noise. It all has to dowith the structure of sound itself. Sound consists of waves inthe air caused by something vibrating, such as a vocal cord ora speaker cone.A simple way to represent a particular sound is a sine wave,which looks like a series of identical peaks and troughs centeredon a baseline representing zero vibration (see DiagramA). As the object vibrates back and forth, it causes waves inthe air like ripples on a pond, which resemble the hills andvalleys of the sine wave. Louder sounds have taller peaks andlower troughs (that is, more amplitude, or volume). Higherpitchednotes have peaks and troughs closer together (meaninghigher frequencies of vibration).Pure notes, such as a single piano key's, produce clean sinewaves, such as the one in Diagram A. More irregular sounds,such as someone's voice or a song, produce more complexsine waves. The noise in an office with air conditioning, backgroundmusic, and conversations might make a sine wave thatlooks like a dense scribble.The key to noise-canceling technology is to produce audiothat matches the sine waves of each sound in the area-butwith a key difference. The new sine waves are exactly 180degrees out of phase with the original sounds, meaning theyhave valleys where the originals have peaks and vice versa.One vibration effectively cancels out the other, resulting in anoise reduction. This results in sound levels that are close tosilence in all but very loud conditions. (See Diagrams B and C.)
Besides a little peace and quiet, there are other benefits to active noise control, says Dan Gauger, Bose Noise Reduction Technology group senior engineer. Noise cancellation improves the fidelity of music played through the headphones and also cleans up distortion and reduces background hiss, he says. If the user simply wants to cancel noise without listening to any other audio source, she can detach the QuietComfort 2's audio cord and just enjoy the silence. Other benefits are more practical. "If you find yourself exposed to low-frequency noise for an extended period of time, like if you're traveling, that can be fatiguing," Gauger says. Many of Bose's noise-canceling headphones customers have contacted the company about using the devices in transit. "About three out of four tell us that they end their trips feeling less fatigued, more able to get out of the plane and go do what they need to do." Bose also makes different models for airline pilots and other professionals who deal with constantly loud environments. Noise-canceling headphones are "like a portable volume control for the world around you," Gauger says. "Maybe I should actually say (they're) more like a portable mute button."
If You are interested in more informations then visit the http://www.smartcomputing.com/articles/2004/s1501/09s01/09Graphic.pdf?guid= ...where You will find details incl. pictures etc.
It is not easy to find detailed informations how it works in case of products available on the market as its mostly "restricted by sales". If You are interested in the N-C effect and You would not like to waste so much money then You can try to build ownself. It's not possible? Oh, yes of course it is. The method maybe will not be as same as the high-end products using but it is good chance to test it easily.
In my case I am planning to try it to reduce noise on 160m band when high noise coming even separate receiving antenna is used. I prefer to use some project which was already tested by somebody so I can recommend to follow instruction in an article below.
The Process of building N-C headphones ownself
Before we started, we considered trying the following experiments:
  • Sound canceling using analog devices
  • Sound canceling using software
  • Noise cancellation specific to erasing ambient noise and keeping directional noise
We decided to start with sound cancelling using an analog circuit, and go on if we had time (which we didn't).
We obtained:
  • Hi-Fi opamps
  • several resistors of varying resistances
  • two stereo audio jacks
  • electret-condenser microphones
  • two pair of headphones
  • perfboard (that we didn't use)
  • bread board, wire, etc
Experimentation
We started by building the circuit. As we went we got a lot of circuit debugging experience! We learned the truly inifinite benefits of the multimeter.
We then moved on to the headphones. We had two pair, one to use for the actual headphones and one to use just for the wiring.
So, for the use of the microphones, we had to sacrifice a pair of (cheapo) headphones. We put them on a stool and said some kind of chant, holding them above our heads. Then we snipped the wires. We found that each of the left and right headphones had two wires going to them, one being ground and one being the signal, of course. We then soldered these wires to the mics.
As you know, we were using low-quality headphones, and when we mounted the mics on the outside of the headphones, we got little beneficial effect. We found that we could get better results using nice headphones, but they still were not very effective. We moved mics inside headphones to decrease sound delay effects. This greatly improved performance, but introduced feedback until we rigidly pointed the mics away from the headphones' speakers and covered the mics with headphone foam (from the pair of headphones that we had to sacrifice).
Soon, we were doing our best to make the whole system work. We found that due to sound propogation delay, non-inverted output (in our case) produced better effect than inverted output. We also observed that headphones were ineffectual for high frequencies, so to reduce noise produced by the circuit, the input was put through a simple RC lowpass filter with Wo=1K.
Results
  • The apparatus heavily attenuates sounds of very low frequencies, and somewhat attenuates all frequencies <= 1Khz
  • The headphones also get rid of the part of your voice that "echoes" in your inner ear-- the extra echo that you typically hear when your ears are covered and you speak.
Inverted Signal
Non-Inverted Signal
Well the article over there tried to explain basic principles of few methods to cancelling the noise. An example of experiment with inverting the phase of the signal etc. If You would like to do it ownself then visit original pages http://www.headwize.com/projects/noise_prj.htm with much more informations and contruction details.
73, Petr OK1RP
...-.-

Noise Cancelling Headphones - part III.

20. listopadu 2007 v 17:41 | Petr, OK1RP |  Technical topics
Photo
Hi,
in preview articles I wrote about different types of N-C (noise cancelling) headphones which are reachable on the market.
The NC-2 or NC-4 was the cheaper headphones types published by Roger Western, G3SXW in FOCUS 66 - Spring 2006 (Republished from November 2005 CDXC Diges, bi-monthly journal of the Chiltern DX Club.)
As I am interested in that headphones to test the noise cancelling effect in combination with other noise reduction filtering I tried to find them on the market.
The NC-2or NC-4folding design
are still but hard reachable so I looked for other available products from the supplier.
Fujikon Industrial Co Ltd is another Hong Kong company committed to keeping pace with rapid changes in the international home and portable audio industry.
As I found the information currently available on the internet "Fujikon has also built on the success of its NC-4 active noise-cancelling headphones with its new NC-42 model, which features a 90 deg. swivel fold-flat design for greater portability and storage, lightweight extendable headband for added comfort, airline adaptor and carrying pouch.
Driver Unit
2 x 30mm
Frequency Response
20-20kHz
Impedance
32 ohm
Sensitivity (at 1 KHz)
115db (Off)\r\n121db (On)
Reduction Level
15dB
For more informations or another types of Fujicon N-C headphones visit http://www.fujikon.com/eng/product/audio/fh/nc/noise_cancelling.jsp
If anybody know good supplier of these headphones with fair prices and shipping conditions in EU then please put to comments below an article or send me an email please.
73, Petr OK1RP
...-.-

LX2007L - European Capital of Culture 2007 Award

11. listopadu 2007 v 19:24 Band reports

Luxembourg - European Capital of Culture 2007 Award bringing the people of Europe together'

After being city of culture in 1995, Luxembourg made it again and will be European Capital of Culture 2007 together with the Greater Region, Germany (Saarland, Rhineland-Palatinate), France (Lorraine) and Belgium (Wallonia).
The Greater Region is about 65,401 km2 large with 3 spoken national languages (French, German and Luxemburgish) and has around 11.2 million inhabitants.
More information about Luxembourg and the Greater Region can be found at the official website www.luxembourg2007.org
Award Rules
The Award is available to licensed radio amateurs and short waves listeners.
Beginning January 1st 2007 and ending December 31st 2007, two way contacts must be established with the 3 special event stations
LX2007L (district of Luxembourg)
LX2007G (district of Grevenmacher) and
LX2007D (district of Diekirch)
and 5 different LX - stations
Each station may be counted only once. Contacts made via active earthbound reflectors, repeaters and echolink may not be counted. There is no restriction on the mode used
Applicants should submit a list showing the date, station worked or heard, time, frequency and mode, please use our application form available on the RL-website www.rlx.lu. Any dispute concerning the award shall be settled by the RL Board
The application fee is USD 8 or EUR 5
Applications shall be sent to:
Réseau Luxembourgeois des Amateurs d'Ondes Courtes
Awards Manager
P.O. Box 1352
L-1013 Luxembourg


QSL Information LX2007L, LX2007G, LX2007D
Your QSL-card is not necessary.
All QSL-cards for the 3 special event stations will be sent automatically by the RL.
However, please check our online Logs at www.rlx.lu
For any questions please contact lx2007rlx.lu
Final Logs will be available on EQSL and Logbook of the World by 31st December 2007.
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Well I worked LX2007L just few mins ago on 1826.8 even with my horrible sigs using 5W out so it seems to be reachable that award also on Topband. There were no mni takers so it should be easy to work them.
Best 73, Petr OK1RP
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