VU7T Lakshadweep DXpedition

Just returned from a Radio DXpedition to Lakshadweep.
Following is the regional news coverage of this event:
http://www.deccanchronicle.com/nation/in-other-news/111017/grand-get-together-on-air.html

Lot of learnings, friendly people, joy of spreading awareness about Amateur Radio and many more hams across the world getting their most sought after DXCC score made this trip a fulfilling experience.


Cheers
73
Kiran VU2XE

Youtube live event on Radio Contesting

Amateur Radio is taking me to many areas of learning. Recently, i have been elected to Amateur Radio Society of India as a GC member and then got requested to play Contest Manager role there.

I believe in learning and sharing the knowledge all the time. Thought of reaching VU hams via newer mediums such as Youtube live events. I attempted first live event today at my following: Amateur Radio Channel :

https://www.youtube.com/channel/UCgcvEOny7T5AGbQksYowPsw/videos

It took good amount of hours (probably 25 hrs over 3-4 weeks  to collect materials, format slides, record and edit all necessary elements.

Software used:

1. Videopad for editing
2. OBS for streaming
3. QSOOrder (connected to N1MM during contests) for sound clips
4. Bensound.com for sound track

What I gained? - many friends in ham world and learning of new techniques in the process.

Cheers!
DE VU2XE
Kiran

SWR raise with Power and troubleshooting

We are hit by late Monsoon rains here in Bangalore. Probably month's worth of rain down poured within few days last week. It is the time when hams here normally need to be extra vigilant about antenna and open area transmission lines for any moisture traps in the line.

During WAE SSB contest (9th and 10th Sept 17) while giving WTC, I noticed that suddenly otherwise all good SWR shoot up and drowned the signal putting my amp on alarm mode. Went to terrace to check all the antenna parts and coax joints etc. I have a Spider beam and a 40 meter vertical connected with separate Coaxes coming down to shack where they end up in the Antenna Switch, then to Directional Coupler for my SWR/Power Meter, then to LDMOS Amplifier and finally to TS590.

I found that small drops of water inside of the spiderbeam antenna coax joint. Shook that part to drain any drops out of the joint and then put insulation tape again on top. Back to shack, it did not seem to improve the SWR. Even with Amplifier on  bypass mode, i could see SWR going over 9 on power meter.
I suspected that the homebrewed Balun box at antenna feedpoint getting flooded due to rains. I didn't had any drain holes made to them to take care of such situation. This means, i had to lower the spider beam which is a cumbersome task for me..

Many of my friends VU2PTT, VU2IBI, VU2DED, VU3NXI and others provided some very good tips including how to check Coax separately, Checking the connector etc. I thought i checked everything.
Couple of days later, i just connected Coax coming to shack directly to the rig, bypassing all other jumpers, power meter, power amp etc. I could see SWR as expected less than 1.5. wow!. When I connected back to Antenna switch, again SWR shoot up.. So now it seems i have cornered the problem.

But then, that evening again i started some more test. I connected coax directly to TS590 and started given 100W for few seconds. I could see that SWR raising from 1.2, 1.3-1.5 , 1.7-1.9 and then 2.5 and i stopped. This indicated that my problem is not so easy to solve.

I then went for Time Domain Reflectometry (TDR) with VNA to see if i can detect anomalies in the Transmission line. Following images show the patterns i observed. First one is for line running to 40mtr vertical (it has LMR 400 25 mtr and 15 mtr lengths), second one is for line running to spiderbeam (it has RG213 25 mtr and 10 mtr lengths) and last one is brand new 15mtr length quality 213 rolled in my shack with one open end.

I could make that on RG213 line running upto the coax junction, there is no reflections and segment is holding good on pattern. It indicates to me that, line is clear of any water content. Then i went and checked the barrel joint to find a sticky type of material on center pins. So, replaced the barrel connector with the new spare one i had  to find that the Spiderbeam is now giving the expected results!.
On the Vertical antenna path, i noticed that the crimped connector on LMR400 is freely rotating giving up ground connection. This requires replacement of my coax till i get a new crimp done.


So this troubleshooting continues...!

Enjoy
73
Kiran

I cannot afford an island! – Living with noise in our times

For sometime i was pondering about RF noise. I have seen and read many articles about fighting noise in the past. There are great articles out there for those who wants to jump in and get those well proven methods implemented. I wrote this article couple of week ago trying to think bit differently.

Hope some of you will find interesting as well and probably attempt concept mentioned here.

Please check this PDF article at following link:

https://drive.google.com/file/d/0B8FrRlsLMAHpQi1XMEE1VENyaHBmNGlmNkRic2ZoaVJQYm93/view

73
Kiran
VU2XE

What got me here, will not take me there ! - experience from CQWW CW 2016

Writing this blog post as I just return to normalcy of life out of the biggest CQ contest of the year!

Learning a lot from this year's contest, thought of sharing it will readers here. Hope you will enjoy..

Last year by this time, I had just given license upgrade exams and was awaiting results. As VU3KPL, I had distinct advantage of the low power (50W) and my operating style which was mostly Search n Pounce (S&P) during the contest and intermediate runs on the higher bands. This skill was built over few years which gave me a lot of frustration and fun at the same time. Frustration when stations could not hear me well and fun when my 50W made a big impact all over for short propagation duration.

This time as VU2XE, a minimum 2 S unit difference was available with me, but....

1. Power to run is great , but do not forget about S&P for juicy multipliers:

Difference being, this time a perfectly working LDMOS amplifier which I could drive to VU legal limit upto 400W, but overall lower propagation conditions. This amp dragged me into running more, and less of S&P. Some moments during the run were so fierce that I could not pick calls as fast as I would have otherwise. This might have driven some high speed callers away and bringing my run lower than 120 Qs/Hr. Not bad in usual case, but during those narrow propagation windows we observed during the weekend, it proved bit frustrating. These runs got me into another mode of "wanting more" on run whatever it may be, forgetting the juicy multiplier search elsewhere.

2. Turn off DX cluster window if you are not using it from the start:

Important aspect which I did not consider was finding some mults using cluster spots. Never used spot window effectively because of the rush during the contest. I have to be frank to admit that, I only used it while parking my run frequency. It is considered by me as using assistance, so logging as Assisted mode!. If you turn on cluster window, do some justice as mentioned in point #1 above

3. Propagation may swing rapidly and get the best out of it:

A pattern observed during this contest was about 20m band conditions. In recent months, 20m normally stayed open till 14:30 or 15:30 UTC to Europe and then only to NA and Caribbean for some more time. This time, it closed to all directions by around 2:30 UTC or so. In small windows towards NA, there were big stations calling me such as K3LR. But they were RST 559 or so. Some stations, i could hear trying to make Q with me but vanished under QSB :(. 

On the other hand, 20m showed best of its colors to me during the day time. I think it must have been open since mornings, but my operations only started after 9 UTC on 20m.

4. Lower Band antennas are must:

We are entering into no excuse years. One who concurs 40 and below will be on the winning race for sure. I did not have great antennas there. With OCF dipole and lower power, I managed 140+ Qs on 40m. There is lot more improvement on lower bands at my station required for sure.

So, these are some takeaways from this contest which is ultimate test for contester's preparation, skill and station quality (only big variable being propagation!)

See you on air

Kiran VU2XE

CQWW SSB 2016 SOAB HP - VU2XE

It is that time of the year when Hams around the globe warmup and charge ionosphere to create their own Propagation Conditions. And this is Year 2016 with downward Solar trend. Let us enjoy every bit which is there to offer by Sun god!

 

Preparations:

Often it is told that test results are only as good as its preparation. And such preparations can run for years together and certainly in my case it was. 

Few major things i had aimed for last year were:

1. License upgrade (read my blog on upgrade advantage in VU )

2. Better Antenna

3. Decent amplifier

I am fortunate enough to accomplish these key goals for my hobby this year starting first with my call sign from VU3KPL to VU2XE as general (advanced) license grade, then upgrade Hexbeam to Spiderbeam and finally getting W6PQL amplifier project working. Here is my journey for you to enjoy!

License upgrade:

As soon as i decided to upgrade my station last year around August (probably pondering over it for couple of years), other than taking upgrade exams, I started researching about amplifiers. Though i reside in Bangalore, my affection towards my hometown Mangalore and its friendly people drove me to take exams from the same monitoring station that took my first license exam during year 1995-97. With great help of ham friends, i appeared for the exam and completed first hurdle required in last week of October 2015. Thanks to VU2MTT, VU2NXM and lot others who helped me with preparation of the exams, which not only included 12WPM CW, but recently some advanced topics in rules. Numerous followups to WPC wing at Delhi resulted in upgrade granted by mid of this year. I must say VU2XE was not my choice. I had requested them to provide 2 letter callsigns because of my contest interests. Though two letter request was honored, my choice of letters were not. I am getting used to it and it sounds nice.. hi hi!

Amplifier:

Around the same time, I got to know about W6PQL (Jim) amplifier kit. Though there were less expensive options were available, i took this project because of exhaustive information shared by Jim and upcoming popularity of LDMOS. It not only was expected to put me on air with HP category but also help me to refresh my EE skills and put that in practice. I must admit that it was real journey since then. Building each bit of the project such as sourcing components, putting together home lab for assembling and testing itself became year long fun activity. It was more than melting solder to parts and screwing things down. At each stage, understanding RF concepts and testing them for perfection became addiction along the way. And that means, building/buying testing equipments as well. In VU, our legal power for advanced or general grade is 400W and this amplifier could deliver three times of that power. Working carefully with continuous remote guidance became vital aspect. Thanks to Jim, who responded almost as if he is in VU time zone most of the time!. 

Me working at apartment balcony converted as lab ?!

Mouser and element14 became regularly visited for quality components along with local S.P road electronic shops in Bangalore. Project's enclosure came from a lab equipment enclosure dealer in Mumbai who supplied extruded aluminum chassis. Later learnt that similar 3U/4U type of chassis could have been bought at local computer supply dealers. Jim had also mentioned 2D design of front and back plates of the amplifier. In absence of online laser cut firms such as Front Panel Express mentioned by Jim, I had to design my own version of the plates and get it cut at local laser cutting shop. For me, I live just next to Bangalore's biggest Industrial estate- Peenya. Where world class electronic and mechanical industries have their shops. 

Clockwise - Kevin W9CF, Lee KY7M, Andy NY7N, Bob K8IA, 
Kiran VU3KPL, Mike KC7V, Ned AA7A, Gary N7IR

Again nothing is cheap when it comes to quality. In Feb/March 16, I got opportunity to visit Arizona, USA for my morning QTH activity. I happened to chat with Jim on phone. What a pleasure talking to him. Hams around the world share common spirit of designing, building and having fun on air. During the same time, I got acquainted with K8IA Bob and Arizona Outlaws Contest Club. A fine group of Contesters, DXers and DXpeditioners such as this is inspiration for any ham. It gave me my first hand walk-in experience to multi-two contest site of theirs at Bob's residence near Phoenix AZ during a contest.

LDMOS Amplifier ready for integrated testing!

Returning back to home country, a lot of solder flow and drill work later, finally during September 16, the amplifier got into the enclosure box. And by now it was time to perform smoke test without causing smoke out of any parts hi hi!. Fortunately all worked, except for readings on Forward and reverse LED graphs. This may be cause of first time RF assembler mistake such as wiring in the enclosure etc. However, this troubleshooting continues as we go here..

Just a week before the contest, I had tripped my SMPS 800RE (800W DC SMPS supply from Connex Electronics) without understanding RFI issues and damaged it. Panic stuck me ordered used ESP120 ( HP Blade server''s PSU) locally and this time I placed toroids at input DC power lines just in case issues continued. This beast supply (OEM spec'ed at whopping 2930Watts!) has personality of its own with booming fan sound in the background and not even a drop in voltage providing adequate juice required for CQWW without a blink! 

This amplifier setup played awesome role in my 15m and 10m run this time pushing VU legal limits without any hiccups. Though 20m had problems due to higher SWR which on second day i resolved using loaned MFJ tuner limited to 200W out.

Boy.... being first time beyond 50W level, it is surely a adrenaline rush when stations lineup for you!

Just joy to say Five Nine TwoTwo :)./ with your own handmade amp talking hi hi..

Antenna and Propagation:

Spiderbeam around 15ft above my Apartment terrace (140ft)

In April-May this year, i took down my homebrewed Hexbeam and cut its spreaders for shaping it as Spiderbeam. Within a week, early Monsoon rain and winds fractured its spreaders. The spreaders i used were local and holding good for my Hexbeam earlier due to its mechanical structure. However with Spider, wing span takes special attention for sure. Ordered Spiderbeam spreaders from Germany and finally new structure was made ready when still a month to go for CQWW. This definitely adds 2Db over my hex (is it 1/2 S Unit?)

Antenna proved its goodness for sure with lot of JAs in our local mornings worked and EUs in the rest of the time.

Propagation stayed erratic. With major storm passing (Flux 79, A 26 and K 4), it was not expected to be great contest time. There was no hope on higher bands, but then 20m also closed just while after 10PM local (16:30 UTC). 40 and 80 would have been the good bands, however, i had recently downed my OCF dipole for LMR cable to connector issues. No sweat there, probably it is due for CQWW CW. 

Summary:

For me, these contests  are a big inspiration and drivers to improvise the station and my knowledge. I scored 600+ Qs for the first time on SSB and definitely it is not near to any VU HP marks. However, I earned a lot of knowledge in the process of working them. All these years I stayed below 50W level and worked the world and had admiration for those big guns with sensitive ears. Now I started developing even further respect to their work on preparations.

There were not many wow moments this time working Caribbean and South America  from here. Each QSO out of my brewed amp was a like a Diwali gift to me :). One YO station greeted me "Namaste, Happy Diwali Kiran! you are 59 ..". Thank you dear - truly, it is our largest festival time here in India and I enjoyed every bit of this contest while overlooking Fireworks from my apartment window at night!. 

Couple of QSOorder recordings are embedded here for your interest. Check how my station hears you! 

Clipping from one of the best EU run i had 128 Q/hr with 300-350W on 21Mhz. Though lived short, it really made me happy!

Listen to following snip from K3LR QSO. He picks me up in clear one shot! No wonder 250 watts works better on 20m than 50W i used to earlier. These big gun stations are beacons for us over the pole :) 



Here is finally score from N1MM software:
 Band     QSOs     Pts  ZN   Cty  Pt/Q
    14     143     400   16   43   2.8
    21     371     970   21   76   2.6
    28      92     168   10   25   1.8
 Total     606    1538   47  144   2.5

Score: 2,93,758

Looking forward for CQWW CW in November!
Cheers

Kiran

Update 7th Nov 2016: Just an update on the LED BarGraph reading related issue. It got resolved on 6th Nov finally. I will write a short blogpost soon on this troubleshooting exercise and with Arduino sketch of the project etc.

Antenna Switches

Hams are experimenters by nature. It is proven fact that if there is an investment to be made in the station, antenna should be considered first. This is because transmission signal quality in a given direction is well tied to the antenna. As soon as we go for multiple antennas on our roof, need for multiple transmission lines becomes a need. Often this is found to be cumbersome to lay multiple coaxes. Antenna switch is a simple device which can be placed near to antenna system with a single coax and a control line running to it. Although it is simple switching device, poor quality of relays, boards and even the enclosures can yield to losses or even interference. 

Following are the key considerations when homebrewing or buying an antenna switch:

1. Number of antenna ports
2. Insertion loss
3. Port Isolation
4. weather and EMI proofing
5. Mounting mechanism
6. Control device
7. Control line

Number of Antenna Ports:

How many antennas you would like to have switched. If moderate space is available on the roof, it is quite normal to find 2-4 different antennas. A mix of vertical for lower bands, dipole or beam is common. in certain cases upto 6 antennas can also be found. During the operation if that ham finds one antenna better than other in that condition, he can quickly switch between them and continue.

Insertion Loss:

Antenna switch being inline component between the antenna load and the transceiver, due to the fact of additional contacts in connectors, relays etc. there will be some loss  introduced. Our aim should be to reduce the loss as much as possible. You will have to select quality connectors, relays for this and ensure that the loss is not significant.

Port Isolation:

When one of the relay is activated other how is the coupling behavior with other antenna relay ports matter. More the isolation the better. Reduced isolation will result in unwanted signal leakage through that route.

Weather and EMI proofing:

Antenna switch being outdoor device, selection of the material matters a lot to protect inside from rain, sun, dust etc. Preferably galvanized steel or powder coated aluminum casing with rubber gasket inserts gives a long lasting protection.

Mounting mechanism:

How and where are you going to place the switch should be planned in advance. Most hams prefer mounting the switch to the mast and some mount to the wall near to the roof. Following are some arrangements – flat mounting(with anchor bolts/screws) provision for the wall, worm drive clamp mast mounting,  step teeth and U bolt mechanism. All these have their uses and depends on individual situations and preferences.

Control Device:

While antenna switch is remote, control device is always near to operators. It even simpler device with rotary power switching to trigger respective relay in the remote switch. It typically contains a visual indication on switching port as well. Aesthetically it control device should be stable(should not wobble around the table) on the shack bench and gel well with your rest of the equipment.

Control Line:

Care should be taken on Control line as remote end of it terminates in antenna switch and has great degree of RF exposure. Control Line should have EMI suppressors applied near the antenna switch. Also shielded cable should be preferred. Normally there is no much DC current flowing through them (depends on relay resistance and line length). Watch for cable specifications on resistance/100 meter. If you are running significant length of control line, to carry current required to trigger relay may drop in the line causing relays not to trigger.

In summary, even a simple device when considered for optimal performance has several factors which makes it or breaks. Do not compromise on cheaper components. Consider something which will give you years of operation without maintenance.