07 November 2014

NAS - Directional Power Meter R&S in lab


the RF power meter is very usefull in the lab and for ham radio experiments it is even most important measuring equipment...

I like the Rohde&Schwarz in general. I like their equipment for long time and last month I was lucky to find their analog precise power meter NAS in very good shape available for acceptable price.

Directional Power Meter R&S®NAS is the ideal servicing unit wherever power and SWR of all kinds of radio equipment have to be measured. Insertion units for the whole field of mobile radio - including GSM applications - make the R&S®NAS a versatile unit and an investment for the future.

  • Two moving-coil meters
  • Autoranging
  • Battery operation
  • Automatic switch-off
  • High EMI immunity
  • Wide range insertion units still available up to 1GHz

  • The insertion units can be connected directly to NAS RF voltmeter or it can be connected thru extending cable.

    I grabbed the NAS voltmeter including the Insertion Unit (1 to 30MHz, 1200 W - NAS-Z2 and even the R&S carrying bag has been included. So I got complete set to measure RF power on HF up to 1kW (1.2kW max.) with 6.5% of rdg for Z2 + 1.5% of selected range of NAS uncertainty. Great value to my lab for that money.
    As I was a bit nervous how the postal service will manage the shipping I decided to pick up it by myself from Germany re-seller. So I made quick visit the Germany by car and after 9hrs on the way and 1000kms I arrived in the late night with my NAS equipment.
    New NAS power meter in the lab...
    Automatic self procedure after turning On the meter tells "all ok". The battery inside is newly replaced (thanks to re-seller pre-sale service) so I can go to follow the auto-calibration procedure according to user manual. It will need more time so not done yet but I am confident.
    My first measurement has been done on the old Yaesu FT-990AC which showed me the max. power of this radio 110W at 50Ohms load. (no uncertainty calculated yet)
    So in general all seems ok and I am happy to be able to measure RF power on HF precisely up to 1GHz.
    If You will find this unit somewhere for acceptable price then do not thinking about it so long time and grab it.
    73 - Petr, OK1RP

    19 September 2014

    The 40m BPF to improve the reception in MM/HP contesting


    when You are contesting in MM/HP category then You know very well that filtering is most important on each band...

    In our case the 40m band was the biggest problem mainly because of breakthru from 160m band.

    Even although the band decoder/PA lines used the proper TX BPFs for each band the reception on the 40m band CW was nightmare when 160m band operator operated the RUN station.

    I started to modifying the lowband setup step by step... At first I installed the front-end savers into all external RX inputs of transceivers and decided to build good more-order BPF for 40m band receiving path.

    I prefer the rugged and well shielded box for this filter to avoid blow-by the signal so decided for Hammond alloy box. It is really expensive but "You have what You paid for..."

    As I had not enough time (as always I started to solve this issue just 1-2 weeks before the CQ WW) so I did not spent time with PC analysis, PCB layout etc. Simply I found and used the good design from W3LPL (mni TKS guys) and though "Network analyzer will say more..."

    If You are going to build Your own filters also then do not use unknown or low-end components for the filter. High quality NP0/Silver Mica capacitors and Amidon cores (Hi-Q) as same as high quality connectors (PTFE) is the goal.

    After assembling the filter on the breadboard I realized that the PCB is installed too high in the box and the cover is just 1mm above the components itself. In order to avoid the unwanted influencing of the filter and it's final performance by the closed cover I decided to reinstalling it and drowning the PCB as low as possible in the alloy box. It was not easy as the connectors did not fitted to PCB as at the beggining...

    Well finally I solved all issues and even I found the way how to properly grounding the components together with alloy box and connectors with minimum junction points.

    The first shot on the Network Analyzer (thanks to Mr. Hewllet and Mr. Packard) was not so satisfying...

    I was not happy with the ripple as same as the insertion loss was a bit higher then I expected.( Network Analyzer has been actually calibrated and used measuring coaxial cables has been compensated properly)

    Although I kept all values exactly as stated in W3LPL cookbook (even the coils has been tuned on the RLC-meter for their proper values)the slight modification has been needed.

    After short alignment the BPF seemed better. I had to remove some wire (1wdg) and modify the coupling capacitors between the LC stages to get better response without ripples.

    Also the insertion loss went down for 0.5dB (although it is still not satisfying for me and it will need some time in lab) and I decided to keep it like that for the coming contest.

    Final result after tweaking and then closing the box is not so bad. The main goal the stopband on 160m band looks like over -100dB and the insertion loss on 40m is slightly over -1.5dB.

    73 - Petr, OK1RP

    11 September 2014

    Noise cancelling headphones - part II.


    in preview part I did not mentioned anything about the "second" way of the noise cancellation which I named in my article "the passive noise cancelling" method.

    As I realized that it is a bit confusing so I am going to try explain what I mean by these ways of noise cancellation...

    Active noise cancellation

    As I already mentioned more detailed in the first part - the noise cancellation (more or less known as ANC) takes an active approach to blocking-out an external noise. There are one or more microphones built into the headsets to detect external noise. Using the electronic signal processing an "anti-noise signal" is then generated to cancel-out the external noise.

            Bose QC-15        
    In fact it is leaving only the desired outside disturbing noise that is reaching Your ears in the room. With a pair of good ANC headset You should hear your intended radio signals without any background noise.

    Passive noise cancellation

    The passive noise cancellation does not make use of any electronics to blocking-out surrounding noise. In fact it is using the different of construction materials and an ergonomic design to blocking-out as much background noise as possible coming to the ear canal. With respect to this fact it is better to talk about "noise isolation" instead of cancellation job...
    For big headsets (mostly known as over-ear) it is commonly done by soft and thick memory foam earcups padding that fits snuggly over your ears. The fact that it fit "airtight" inside your ears keeps the noise out.
    For in-ear earphones which are probably not used for ham radio applications so often the eartips are ergonomically customized to fit securely in the ear canal which effectively forms a sealing chamber within the ear canal and blocks out external noise significantly.
    So in summary...
    Noise isolation or passive noise cancellation or noise reduction

    is provided when headphones totally cover the outside of the ear or ear buds can be used that fit snugly into the ear canal thereby preventing external background noise, buzzing or sound reaching the listener in the first place. Passive noise reduction (better we should call it noise isolation whenever) is mostly used to cancel-out unwanted high frequency sound which is difficult to effectively removing using an Active Noise Cancelling (ANC) system. This is the reason why better headsets are using both - good noise isolation as same as the ANC gadget inside...

     Goldring NS-1000

    For example in my small radio room I measured over 78dB of background noise when all power amplifiers, power sources, computers and other fan's equiped stuffs running and it really make sense for weak signals pulling out. Just to compare > when all is down the ambient noise is measured around 30dB in the room. So this is my personal reason of looking for good quality and effective ANC headset.

    Another headphones test by Mark, PA5MW can be found here.
    Hope it helps a bit.
    73 - Petr, OK1RP

    03 September 2014

    The best AGC setting for weakest lowbands sigs pickup on Elecraft K3


    as I am lowbands enthusiast and the Elecraft K3 transceiver owner also... I am interresting in any kind tools, h/w as same as K3 setting how to pick up the very weak CW signals on the lowbands (160/80/60/40m).

    I started to play with wide variety of AGC system setting in my K3 and I am currious which kind of setting is used on K3 by other users...

    The links and sources which I already visited (documents for study/research):


    In fact I used for long time the AGC off in cases of pulling weakest sigs out of the noise but specially in pile-up it was really danger when the strong sigs attack my ears.

    For that reason I would like to use all of opportunities of AGC system in K3 with proper setting. So I will be happy for any kind of settings hints and experiences for CW weak sigs handling.

    I am trying to play with the AGC system setting in order to optimize to my needs (weakest CW sigs on lowbands). I am sure that it will be different from other users also because of my local background noise/noise floor environment, disturbation and other noise sources...

    My original setting was for years as follows:

    AFV TIM: 1000 / AGC DCY: NOR / AGC HLD: 0.00 / AGC PLS: NOR / AGC SLP: 14 / AGC THR: 3 / AGC F/S: 120/20

    ... but it sounded so noisy and I commonly turned AGC off in order to get quieter RX for weak sigs. Of course that I was attacked by strong sigs in pile-ups or contests and I was punished when AGC was off.

    After some discussion on Elecraft reflector I got few recommendations from which I finally decided to try this config:

    AFV TIM: 1000 / AGC DCY: SOFT / AGC HLD: 0.20 / AGC PLS: NOR / AGC SLP: 000 / AGC THR: 8 / AGC F/S: 200/20

    ... which was recommended by several users for weak CW signals reception. (many thanks to Merv, K9FD/KH6)

    I found very quickly that the receiver appeared a bit noisy so I added N1EU pink noise roll-off on RX EQ.

    I used the left side red column settings:

    http://n1eu.com/K3/K3_notes.htm (many thanks to Adrian, VK4TUX)

    It helped I guess but I realized that the behavior of AGC in my K3 with this setting is in general not what I am looking for and I do not like it so much. The improvement is that when there is no signal on frequency then this setting of AGC sounds more quiet than AGC off for now! 
    Unfortunately I do not like the "slow pumping" of AGC which is pulling down the receiver gain some time...

    So I am looking for another settings or ideas and I am going to make more research.

    73 - Petr, OK1RP

    07 August 2014

    Sticky Pen for SMD and tiny parts assembly and handling


    it's few months ago when I came across the plastic handle with tacky head in three different sizes originally used by modellers for glueying and hadling the tiny metal parts.

    It seemed to be very interresting and I got an idea to use it instead of tweezers for SMD parts soldering and handling during the PCB assembling.

    A simple but very effective idea for placing SMD parts and tiny electronics parts when PCB assembly or electronics bench work is here...

    All electronics, modellers, ham radio, laboratory, science and technology enthusiasts, professionals and bench operators who have had troubles picking up and accurately placing the SMD, then just as importantly releasing SMD small parts has maybe the solution over here.

    Tweezers seem to launch small pieces as often as they place them but the parts fall off half the time before they reach their target.

    The Sticky Pen tool will address this small parts dilemma with a simple but very effective and reusable solution. Three sizes are available - Fine, Medium and Large.

    Using the tool could not be easier. Pick it to it's place, heat up quickly with soldering tip the paste and that's it. Each tool comes with a clear plastic cover for the tip. This will help keep the tip clean.

    If the heads get dirty or they lose their tack, they may be restored by simply running them under warm tap water and allowing them to air dry. If they are really gummed up, you could also roll the head back and forth on clear adhesive tape.

    I tried to use the Sticky Pen in my home lab as same as in daily job - professional lab and after assembling several SMD parts in different sizes I can say... it works nice!

    Stick Pen tools are simple but very useful and reusable instruments for all types of electronics, soldering, assembly, modeling etc.

    I can highly recommend them.

    73 - Petr, OK1RP

    01 August 2014

    Shopping for a pint-size Iambic key


    very quickly after posting of my personal recommendation for iambic paddles on www.qrz.com forum I got few emails regarding this task.
    I was asked for more details about some of the paddles (mainly about these of recommended). So I am re-posting there my original article from the QRZ Forum and I will try to write more about it later.

    Unfortunately I can not recommend any of the above mentioned paddles in this thread for many reasons.

    If You are looking for something ready to use, rugged, small, but still usable enough then look for Mini Paddle from Palm Radio:

    Also the good choice can be for You (I have it) the Black Widow (W5JH) or his Baby Black paddle here:

    or AZ Paddle by Arizona ScQRPion here:

    The only issue can be that if nothing changed it is the kit. So You have to be able to put it together including the final polishing. But finally it is nice paddle (it is using springs only instead of magnets) for the return but good one and compare to other mini paddles or plastic junks it is most valuable choice I am sure.
    If You would not like to buy none of these "toys" then You will not make anything wrong with Magnetic Classic from Begali:

    The only problem is with uncovered bearings > dust comes in and makes troubles but You can solve it with "nice label". Also prefer the metal finger plates if You will decide for this paddle to avoid backwards vibrations.

    The Bencher Hex key is very nice and rugged paddle (I have it also) but adjustment is night mare because of rough threads, You will need to change triangular finger plates for metal standard shape, it is really big for portable and it's pricey:


    In general stay far from the toys like Paddettes, KK-1, MK-44, MK-36 and other plastic toys please.

    Hope it helps. Do not hesitate to ask me for any help if You want...

    73 - Petr, OK1RP

    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