16 July 2014

Mercury paddle N2DAN - The Zen of CW Art


the Mercury N2DAN paddle is fabulous CW tool known by all CW operators and enthusiasts worldwide.

Vince's, K5VT Mercury N2DAN paddle
The official description says "Handcrafted Paddle by Ex-European Machinist to the highest quality standards" and all of them were made upon personal requests by Steve, N2DAN and personalized with serial number, owner's callsign and some others.

Although there is a lot another very high quality paddles on the market the Mercury N2DAN paddle is still evaluated as "The Best".

Beautiful, heavy chrome plating, smooth operation, precisely adjustable, right height on the operating table... the benefits of my original Mercury N2DAN paddle #0062Y also.

The genealogy of my piece of Art is very interesting. It made a journey over 3 continents already and the operating behaviour on the air is impressive.

It is heavy weight, heavy precious metal (rhodium) contacts, adjustments that stay put and no vertical movement of the paddle arms. Thanks to Vidi, ZS1EL I am proud owner and really glad to have an original Steve's item.

There are several copy-cat models now available and after Steve's wife sold the patent and it was remarketed it came in a similar form and design.

73 - Petr, OK1RP

15 July 2014

Battery case for Kenwood TH-42E


an older radio's accessories like battery packs are hard to find quite often. In case of the VHF/UHF handhelds the situation is not so bad as some of the new models are using the compatible battery packs and they can be ordered and re-used.

In case of my very old (Made in Japan) Kenwood handy TH-42E which I got from SK estate it is different situation. You can find on the several re-seller's webs as same as on the eBay the OEM battery packs. I do not want to spend money for low-cost cells in these packs so I found on the same source the empty battery case BT-32.
It sounds to me nice as I can load it with my preffered higher quality cells and still I have under control the complete unit. I ordered it and after few weeks it arrived.

It looks good and even I was a bit surprised with the label KENWOOD BT-32 "Made in Japan". The label on the front cover is talking also about 7.2V DC (charging) supply voltage, 5x AA cells size case! I know that it is OEM unit so I did not expected japanesse item to come. The explanation I got after openning the case.

The soldering inside is definitelly not made in Japan and it is real nightmare.

It is typical chinesse piece of junk as I do not believe that japanesse industry degraded to that lowest work-craft level.

So no matter what is labeled on the front cover it is China product. If You will have problem with contacts, charging socket or so then You must check properly the soldering inside the case.

Be careful and do not over-heat the plastic parts to avoid destroying the case or contacts as it is not rugged design in all.

73 - Petr, OK1RP

Update 16 July 2014

The real nightmare will come to You when You will try to loading the case with rechargeable cells!

Trying to put all AA-cells into the case will discover that case itself is a bit smaller. Unfortunatelly thanks to non-flexible and hard (probably low cost) steel contacts the cells are bending the plastic case and distorting it.

Because of that issue both parts of the battery case is impossible to lock properly together.

You can try to bending the steel contacts inside the case by pliers (be very careful to not damage case itself) but it will not fit on both sides of the case.

Finaly if You will try to slip in to the TH-42E transceiver then You will not succeed as it is impossible to lock it.

Simply it is typical piece of junk from China and I can not recommend it to anybody to buy it anywhere on chinesse webs or thru eBay. It is wasting of Your money and You will be disapointed!

73 - Petr, OK1RP

11 July 2014

Listenning to Radio Praha


when I am talking to people about the ham radio activities lot of them asking me what is the SWL or BC SWL and how it can be atractive these days...

My one of the favorite BC station > local Radio Praha is still offers lot of interesting programms and listeners can enjoy also their QSL cards. 

They are preparing different kind of QSL sets and sometime You can be also surprised with gift in the post box like me...

Petr, OK1RP 

10 July 2014

FE-5680A Rubidium standard


my new rubidium frequency standard unit FE-5680A arrived finally.

After some time of "idle" mode in box on the shelf I found the time to remove it and check. As I am planning to install it in my ham radio shack as main reference > here is first short test and some quick measurement.

After heating up and locking the temperature stabilized and stay around +63C...

The first what I wanted to see was the sine wave curve and then quick frequency drift check.

As the start-up of the unit seemed to be as it should and all parameters also I tried to measure the drift in few hours after locking it in order to verify the short term stability of this unit.

The technical specification at glance:

FE-5680 Tech Manual Table 3, Sheet 9 (PDF page 10/19):
  • Frequency 10 MHz
  • Type Sinusoidal
  • Amplitude (minimum) 0.5 Vrms into 50O(+7dBm)
  • Adjustment Resolution <1 x 10-12 over range of 3.8 x 10-5
  • C-field potentiometer Resolution 1 x 10-11 over range of 3 x 10-9
  • Drift: 2 x 10-9 per year, 2 x 10-11 per day
  • Short Term Stability: 1 sec … 100 sec 1.4 x 10-11 t
  • Retrace 5 x 10-11
  • Phase Noise (fo=10 MHz) @10 Hz: -100 dBc, @100 Hz: -125 dBc, @ 1000 Hz: -145 dBc
  • Input Voltage Sensitivity 2 x 10-11 (15V to 16V)
  • Frequency vs.Temperature (-5C to +50C) ±3 x 10-10
  • Spurious Outputs -60 dBc
  • Harmonics -30 dBc
  • Loop Lock Indication: > 3Vdc=Unlocked, < 1Vdc=Locked
  • Input Power (@25 C) 11 watts steady state, 27 watts peak
  • DC Input Voltage/Current
  • 15V to 18V @ 1.8A peak and 0.7A steady-state
  • …(except Opt 25: +22V to +32V @ 1.25 peak, 0.5A steady-state)
  • Ripple +15V: < 0.1Vrms
  • Warm-up Time < 5 minutes to lock @ 25C
  • Size: 25 x 88 x 125 mm, .98 x 3.47 x 4.92 inches
  • Weight 434 grams, 15.3 oz.
An excellent related informations sources are here:

Petr, OK1RP

09 July 2014

Noise Cancelling Headphones

as it is very interesting task in case of cancelling the noise specially for weakest signals pulling out on lowbands I am looking for best solution for long time. The prices are quite different and the quality may vary. I tested some of them but I did not found succesful efficient solution for reasonable price...
Noise cancelling technology

There are two types of ways to achieve noise cancellation, passive noise cancellation and active noise cancellation. Active noise cancellation is to use an extra microphone which emits high pitch frequency to counter the low frequency external sound. Noise cancelling headphones usually use active noise control (ANC), sounds travel through the air or through liquids in the form of waves, and each of those waves has a particular shape. Noise cancelling technologies first rely on small microphones that identify the sounds in a given environment. A digital signal processor determines what sound wave is necessary to cancel the unwanted sound wave and then it generates that sound and amplifies it through speakers or headphones. So basically two different frequency sound waves cancel each other out, thereby bringing the listener closer to silence.

So what’s the point of using ANC?
The main aim for ANC is to eliminate sound (noise) from a single source, prevent listeners from turning up the volume to a harmful level just to cover the noise, as cities nowadays are filled with hundreds of different unwanted noise. Headphone users often got interrupted by the noise. In a result of that users cannot fully enjoy their music. So, the purpose of this technology is to cancel or at least keep to the minimal of the unwanted sounds, in order to provide quietness for headphone users who live in busy, noisy area.
Fujikon NC-4

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.

My favourite N-C headphones NC-42
More informations You can find in the articles written 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...

My related older posts:
N-C headphones part I.
N-C headphones part II.
N-C headphones part III.
N-C headphones part IV.

to be continued...

Petr, OK1RP

07 July 2014

VHF / UHF Field Day 2014


so the VHF / UHF Field Day 2014 is finished.

I participated in the contest with son Jakub from OK5T contest QTH together with the rest of the team. In summary it was nice weekend with lot of very enjoying QSOs on 2m...

The only 100W transceiver in small pistols category using the 2x 12el. yagis at the 220m ASL setup is not predestined to win. On the other hand I have to say it worked well thanks to good condx.
At the beginning HB9, PA and F stations came with nice sigs so I was pleased to start first hour of the contest. The only interesting thing was at the beginning of the contest that most of the sigs had very fast QSB and lot of calling stations disappeared during first shot.

Everything worked well all the time including the second operating position for 70cm band where we spent the relaxing time with giving the points to other stations. Simple setup using 20W into small single yagi was dedicated only for fun on this band.

The most important time for me was Sat/Sun night when I planned some DX-ing on CW. It was a bit dissapointing for me but even although I expected a bit more from this part time I worked over 30 stations over 400km away and ODX 930km into YT.

Sunday morning was the nightmare. Not so many stations came to our CQ and we were not able to pickup the weak stations in the southern EU from the noise. North-West direction with DLs from Rostock and similar far away "sea" areas came to us very hard and weak. Last hour put me back the enthusiasm as we were lucky to work I, 9A and DLs with QRB over 800km again.

                   Mirek, OK1JMJ is ODX winner - 932km

I expected a bit more QSOs in total but total score in points is not so bad finally with used setup.
My son Jakub enjoyed his VHF Field Day "Scouts" part as same as DX-ing on HF with his FT-817ND, we enjoyed the sunshine WX and sausage BB in the evenning so it was enjoyable weekend for all the team I hope.

Thank You to all for nice contest and all QSOs. See You on the air soon.

Petr, OK1RP