Convenience or Compromise antenna for portable HF?!

 It depends on what one considers as good ops!. When speed matters like in regional emergency comms, NVIS strategy is most beneficial. NVIS antennas for any bands are very low to ground often no higher than quarter wavelength. Dipoles or EFHW hung just few feet above ground get this mode going in shortest possible time.

When one is looking for mid to long range distance comms i.e 500Km + and moves beyond those weak signal modes like FT8, JT65 etc., there comes the need of height, optimized antennas or directivity. This article may be of interest to such Ham Radio enthusiasts who are looking into operating beyond regional comms for non Weak Signal modes and do great. This is based on my experiences of last few years on the field portable ops and subsequent 4NEC2 model based verifications.

First thing first - When we look for portable ops such as POTA and field days, one will come across great amount of content on internet webpages and youtube. Most majority suggest use of End Fed Random wire or Halfwave antennas and some use small loaded verticals. But, look, all were looking at activating the park with 10 contacts or having some outdoor fun during the day. Most of the antennas are low to ground or vertical. Especially EFHW is popular because of convenience of multiband operation. Carefully observing the signal reach patterns of their reports, it is relatively rare that they work 6000 Kilo meter+ distances, on consistent basis. One will get to know US operators working other states around or bordering countries. Like wise in EU, they work each other countries and mostly they are withing  couple of thousand KMs. But in VU where is the active ham population to reach? othenr than during regional NET checkin times on 40m? So, mostly one resorts to FT8 or other similar weak signal mode to increase QSO rate (if that is the objective)

I mostly participate in CW or SSB Contests and objective is optimizing DX QSO rates and score with less weight and hassles. I have worked on hill tops, River estuaries, beach areas etc over last few years and evolved my learning with practically building various antennas such as Dipoles, EFHW, Inverted Vee, Verticals (mono band and multi band fan type), VDA (both mono and multi band), Hexbeam and spiderbeam yagis. I would like to keep VDA and Yagis aside this time and focus on portable popular EFHW and verticals.

Following is the Elevation (Blue) and Azimuth pattern for 40m EFHW in inverted Vee configuration 10meter (quarter wavelength) above average ground. Most of the radiation is straight up and at 10deg angle from ground level, it is around -7dB. 

Second plot is for same 40m EFHW at 20m (half wavelength above ground). Now, we can see the elevation pattern is shaping up with -0.13dB gain at 10deg angle. These plots will be same for standard inverted Vee centerfed dipole at fundamental resonant frequency.

But this pattern distorts for higher resonances such as 20m, 15m and 10m bands with additional azimuth wing patterns and lowering elevation angles. Based on the situation they may be taken as advantage or can be disadvantageous.

Advantages of EFHW are many--

a) Requires feedpoint at lower height i.e less coax

b) no more heavy duty pole or support required at center point

c) resonates at multiple harmonic frequencies

If EFHW is similar to dipole, why not just use it all the time?

What the modeling misses is actual transformation loss and RFI. EFHW requires carefully built (often shown as easy to build) 49:1 or 64:1 transformer at feedpoint. And in mono band version of  EFHW, one can construct simple feedline stub to gain the advantage (example JPole) of much lower loss. When operating portable, many compromises made in the name of QRP starting with lossy Coax, fact of RFI pickup is not noticed etc. These can be excuses only for highly tactical and worst case situation, but attentive ham should be careful more than QRO ops as inefficiencies adds up. For example: Let us consider 10W output from Transceiver connected to EFHW with RG58 of 10m length. Let us assume with 1.2:1 SWR antenna. This delivers approximately 9Watts to feed point. A transformer loss of 20% on this 9Watts brings down another 1.8Watts i.e power delivered to antenna will now be 7.2Watts. So, even before one says antenna is efficient or no, we have 28% reduced power already delivered due to convenience we wanted. OK, now most of the time I have been told these losses are negligible and no one will differentiate on the other side etc. I agree to some extent, but on the edge condition, these negligence matter a lot and which could be fixed easily.

Adding a coax such as RG213 or LMR 400 and feeding antenna directly such as dipole ( or vertical) without transformer is next step up bringing the losses to less than 10% (efficiency goal in my case). I made first SSB, CW DX QSOs with simple fan inverted Vee only. High apex works always! Verticals are though directly fed, will pose roadblocks in to efficiency journey if not given attention to its ground system. 

I have both QRP and QRO dual core EFHW transformers in my portable kit as fallback. But do I prefer them over dipole?. No. because there is one more reason I have not mentioned earlier with importance, i.e RFI in the Coax line leading up to shack. Unbalance nature of the random wire and EFHW, forces RF on outer shield of coax in both transmit and receive. While transmit RFI is obviously experienced in causing interference to other nearby transceivers, interconnect wires, and if QRO, tingling sensation while speaking to handmic/keying and distorted audio etc. Receive issue is even worst as it picks up local electrical noises and raises the noise floor. To minise RFI we can add counterpoise wires or choke on the line after few meters from transformer etc. But the point is convenience comes at price.

So what other options?. Ofcourse, there is dipole when 1/2 wave height could be established or verticals good radial system. Following are two plots, one on the left is ideal vertical(needs atleast 16 radials or more) on average ground and on the right side with single tuned elevated radial. While two or more elevated radials provide balanced omni pattern, single radial provides some directivity in the direction of the radial. This type of system was practically tested at one of our early field experiments for 80m band which can be found at Blog post link

Here is overlap of two elevation patterns. My experiences showed that when no other antennas are close proximity, having elevated tuned verticals are advantages as it becomes easy for field portable to achieve better efficiency than few ground level radials.

Also, if we are at coast verticals even work much better at 5 to 15 degree elevation angles for great DX. But dot not get overwelmed with EFHW stung vertically to think it will perform same for all the harmonic bands. Just like EFHW in inverted Vee or horizontal position, distorting patterns on harmonic frequencies, vertical also forms higher angle signals which will not be useful in long range.

So while we chose the antenna at hand as better than none, when there is choice, make optimal use of them for the situation, location and purpose we intend to. Afterall, Ham radio is a learning and advancement hobby, just try these and prove!

Have fun

Kiran VU2XE

CQWW CW 2021 - Multi Two VU2XE and VU2CDP

Note: 3830scores.com has operating notes on this contest:  https://www.3830scores.com/showrumor.php?arg=lRabzesimgvgD

Just after my CQWW SSB attempts at Mulki in South Karnataka coast,, VU2CDP got in touch with me for a much serious multi efforts. I agreed on a low key efforts. We had limited automation resources and hence settled on multi two format just to have both of us operating. Having decided about participating in the contest, next came from where? and obvious choices would be close to Sea having good property space to put antennas. Last few years, I had been scouting for quiet radio places to operate contests as I was restricted at home QTH. One place out of my scouting experiences comes to my mind each time was near Coastal town of Udupi (my first experience at this place with VU3NXI in 2017 posted at http://kiranpadiyar.blogspot.com/2017/12/lowband-hf-experiments-near-coastal.html). We shortlisted that river estuary point homestay(AirBnB) near Udupi with many coconut trees and comfortable self service. It was convenient for me to travel from Bangalore and for  Deepak to travel via overnight train from Mumbai as well. Also, I had kept most of my equipment at my native place which is 80Km southwest of this place. So logistically it was convenient.

South West

Next was antennas, Deepak suggested to have mono banders to reduce interactions. Though my Triband VDA antenna with Triplexer ( homebrewed VA6AM design) and High Power BPF(homebrewed PI4CC design) set I had would have sufficed, There was some tuning difficulty observed last time and I thought it is better to avoid any component failure probabilities or delays due to unconventional antenna designs. So, I got to design  monoband VDA using 4nec2 software with locally available 1Sqmm PVC housing wires. Based on earlier experiences with VDA, I made center cross joint with plastic cutting boards, Coax connectors to go with PVC end caps etc. All three VDAs were designed and wires were cut/prepared for assembly. For RFI choking, we used coax clamp ferrites. For 40m, I had half square array and Spitfire prepared on earlier trips. For 80m, I prepared vertical with two elevated radials.

North West view

Our Homestay was only available from Friday and we wanted two days prior to the contest. Owner obliged by letting us to use the property for putting antennas on Thursday and later they allowed to check-in on the same day as no other guests were present. We found that, two days are very minimum for setting up such station. 

I had reached Udupi on Wednesday for arranging all antenna stuff and doing prelim work like PVC cross arm assembly, cleaning up Coax connectors etc. On Thursday morning, VU2CDP arrived from Mumbai train and after a short rest/breakfast, we proceeded to homestay site. We carried only antennas, ropes and coaxes. Owner had arranged for Coconut tree climber for our antenna hoisting. We quickly got into action with location for VDAs, vertical and dipoles. 

Kiran at far end maneuvering rope for 40m dipole

We chose tallest tree ~60 feet for 80m vertical (it was faithful one which supported our fan vertical for 40,80 and 160 on last operation here), a ~50 feet one for 40m and one more as standby. Within a hour all pulleys with ropes were tied to the trees. We then got in assembling VDA antennas 20m first and then 10m and finally 15m. 20m tuned on dot on first attempt, but later we moved the antenna farther to avoid tree leaves touching the elements and changing SWR.

VU2SBJ Sri, VU2CDP Deepak, VU3DMP Chetan
and VU2XE Kiran at Manipal

VU2CDP with VU2BQN Dr.Manu and VU2NJN Dr Soma of MIT

By afternoon we were done with 20m VDA and 80m vertical. We found that we need more coax and requested our friends VU2SBJ, VU2BQN for help. They arranged for additional Coaxes. By evening time we were ready with 40m Vee dipole (I prepared this dipole with wires of halfsquare ) at around 50feet apex and ~25feet high leg ends. Next day we completed 10m, 15 m VDAs and final station layout setup as well. During the final testing, we had VSWR swinging with 20m VDA. That evening VU2SBJ, VU2BQN and VU2NJN visited us. We figured out a faulty barrel joint and fortunately VU2SBJ had one extra barrel which sorted the issue.

VDA Coax feeder arrangement with PVC cap

Then we were left with N1MM network, where we struggled a bit as interlink was not happening. I called VU3NXI for help and bit later figured out that netbios name had to be placed in Network status-> Edit Computer Address section of N1MM software. This was not necessary in last month's contest as it was detecting other computer automatically. So all sorted, we took a breath. 

Now, It was all upto Sun god to grace some flux on earth and of course He turned his major Spot region and flares this side for increasing SFI over 100 on time for contest!

N6RK Loop for 80m

20m VDA Tuned at once!

 

VU2XE and VU3DMP Fixing 15m VDA

All certain done, we were ready for the contest on time. We decided that we both will run at around 200W only to avoid voltage drops. Both of us got to bed by 11PM (contest starts 05:30 AM local for us). I am unsure whether we got good sleep or no, as the restlessness to get on radio had caught us hard.

Contest morning - started very slow for us, But we noticed that both of us could not run with amplifier even at 200W. So one had to be barefoot. On first day, I went barefoot and Deepak was on his K3+KPA amp - running. This was major setback, because we found 15 and 10 opening at same time in the afternoons. We could see around 1200 Qs by that night. I took early time off at night at about 10:30 PM and Deepak kept on Radio till late morning. 

Next morning, I got chance to run with 400W on my W6PQL amp, I continued most of the time running 15m. 10m was again very good that day and Deepak could not use amp due to voltage tripping issues again. We might have lost working few hundred Qs due to this power issues. We had tunnel opening to NA on second day which gave us a bump multipliers. PY, LU stations were having multiple clear opening to VU and helped us in boosting scores when QSO rates from EU were low. We did not find much JAs in our pipleups this time even during our morning 15m lookouts.

Our VDAs worked exceptionally good as they were only few feet within saline water. Its directive gain and F/B ratios were just amazing. On low bands of 40 and 80 we could hear signals even if someone whispers hi hi!. Overall we made 2735Qs which is very close to our set goal of 3K QSOs, and very satisfied with operations. 

End of contest celebrated with glass of buttermilk!

Few takeaways:

1. We noted that we could have used automated switching to jump on other bands quickly to reduce time lost etc. This contest had many coax changes and mistakes during such change over. Probably its time to put my High isolation A/B switch matrix to use in next one.

2. Simple dipole on 40 and vertical on 80 were good enough choices. Probably next time we will look into some additional directional gain to these

3. Power Generator is must at such portable location for bigger scores. Though we could run on barefoot and one amp, we could not benefit from simultaneous band openings. W6PQL amp uses HP blade ESP120 supply which has broader voltage range than KPA500 which seemed to trip with voltage drops.

4. We need to figure to connect local router with some internet connected Wi-Fi device for cluster spot feeds and real-time score reporting. This time we had to connect our laptops to phone to refresh scores etc. and then connect back to local router. bit cumbersome.

5. Overall getting better with portable contesting going on air time by travelling lite, simple layouts, efficient station etc.

Our equipment this time:

• K3 with KPA
• TS 590  with W6PQL Homebrew amp
• VA6AM Homebrew Low Power Filters for 20-10, W3NQN filters for 80 and 40m
• VDAs for  10,15,20m
• Inverted Vee Dipole for 40m 
• Vertical with two elevated radials for 80m, N6RK Loop for Rx

Our quest to improve operating continues. Hope to see you in the next one!

DE VU2XE

Triband VDA antenna update (V2)

 Last year during CQWW SSB (Oct 2020), I had tried to tune my own designed triband VDA antenna. Whatever I tried, it seemed that antenna was not tuning or getting out well. Youtube video on that effort is at https://youtu.be/tJb-NoXO6V0

Couple of months ago, I was pondering about the issue with VDA and realized that my design was not considering PVC jacket dielectric loading (velocity factor). That  made me to load the model(4NEC2) with PVC jacket and check once again with same dimension. Oh. My.. Yes, I was way too off from the design frequency and no matter what I did on ground, it would not have given right results. 

So, a month back during Covid19 native place stay, I carried the VDA to be installed at my garden and check with PVC adjusted dimensions. And I was finding the spot on tuning. I know, triband on a single pole is compromise due to spacing requirements and height above the ground etc. But this is something I could live when Sea is washing its base, when I travel solo etc.

With this test done at home, I got opportunity to test it right on the beach when I was invited me to operate at Kapu Lighthouse AT8KLH near my hometown. It is a week long activation of lighthouse with many events and teams planning to operate from the location. I did quick recce of the place on my way to Udupi where I had kept most of the cables and poles from last WPX contest. Found very friendly neighborhood and a school on the beach next to lighthouse - very ideal for the operating. There is greater collective story to be compiled once the activation is complete. I am sharing my short 2 day participation experience with VDA.

Putting any antenna on beach during monsoon season is bit of pain, we took 2-3 hours to just put the antenna and secure with guy due to heavy rains. Once it was erected with help of Lakshminidhi VU2WFN, SWR plots were checked to be on CW portion of the band where myself and VU2VTI Murthy wanted to operate. Though I had carried some heavy filters etc. to operate multi, we could not due to lack of electric power at the premise.

Anyone who has operated the VDA from right on the water edge know how signals come. I can make a quick contrast with eating food right out of frying pan (still sizzling) vs somewhat cold but still fresh on the table Hi Hi!. Signals with incredibly low noise and crisp right out of the operator's shack on the other side of the globe. We made a 650+ QSOs with many breaks and change of operators etc. till we closed later evening on 15th. Epitome of thrill when one could be in the center of massive pileup and in control of it!.

Following is the 4nec2(freeware) design file if someone is interested in replicating/improvising.

https://drive.google.com/file/d/155F-yHVCxiO9XVuinu8rqDsIFrOxilXo/view?usp=sharing

There is lot of opportunity to optimize further especially for F/B ratio. Here are some plots from 4NEC2

Note: This VDA requires 10mtr tall support (I used 12mtr spider pole with last two segments collapsed). At the Cross section, I used a cutting board material with drilled holes for wire ties. For cross arms (total length of 2 meter), I could have used PVC pipes, but I had couple of Caperlan fishing rods (1 meter collapsed length). This antenna did not hear anything from back. Just to note, there was a small ridge (15ft tall) at the back side towards south east/east. which might have helped in reducing noise/signals from back. Following reverse beacon report and QSO stats shall summarize the efforts well.

Terrain Analysis matters ! - Correlation to Contest Scores

Couple of years ago my neighbourhood started changing rapidly. Once used to be a 5 Acre coconut grove just 100 Feet north of my QTH was grounded over a week's time. It is the demolition monster drive similar to the one in Avataar movie. Along with hundreds of eagles and birds who lost their home that day, I had lost hope on my peak DXing days! After hearing that it was mega project with 360 apartments spread over 5 blocks of 18 floors each, my spinal felt like just out of frozen ice :(.

One of my senior ham friend did help me morally a bit providing what was unknown to me then called HFTA. That analysis stated that, I will loose my sight in the direction of this building which is 320 deg to around 30 Deg north. And it happens to be prime area for contesting and DXing over the poles!.

Recently I purchased ARRL's Antenna handbook. The CD which came with it contained HFTA software written by N6BV. I got hooked to it once I learnt how to use it. It opened up new paradigm for me on HF ray propagation and study the effect of stacking, antenna height with respect to immediate terrain. In combination with K6TU.net 's excellent terrain data service. I started doing many hours analysis of locations I had been recently as well.

CQWPX CW 2018 was the first contest after the high rise got completed. This contest was to test my understanding and vola... It really did reflect what was predicted. Signals were way down than it used to be. Partially overall HF weather also had a play I am sure.

Following are the graphs of these changed conditions. My terrace is at 140 ft level and around 150 ft from me is 180 ft tall building.

I plotted the graph with antenna at popular 50ft level on flat reference ground(Green), 150Ft level without the highrise (Blue) at 330 deg and current condition with Highrise (Red). Purple bars show %ge times signal arrival based on statistics.

We can see at 150ft level, there were deep nulls with signals below reference level. But then, there was surge in gain at low angles. No wonder why I used to catch K3LR  and other long haul DX before many could hear them. But see what happened to me now. Red line barely rises above reference and gain is no where near compared to peak gain of 16dbi at 7 Deg I had earlier (down by 15 dBi now i.e 2.5 SUnits or more). Less of make and lot of break moments.  We can also see that between 3Deg and 13 Deg there is statistical average of 5% or more signal arriving. All these chances are lean now.

Following is similar graph for 15Mtr band.

And this reflected in my score. I used to have restricted grade earlier and best score was in 2015 CQWW CW with nearly a million points. I could achieve this with 2 element Hex and 50Watts only.  End of 2017 in the same contest I could only manage 600K points, that too with 400 Watts and Spiderbeam. i.e. effectively 9dB (due to Amp) + 1.5 dBi (avg spiderbeam increase) = 10.5 dBi gain.
This gain in forward direction was negated by the high rise on transmit. On receive it is only 1.5 dBi, which will be of no use as building is blocking most of the low incoming signals. In total effect, i may be sounding similar to my restricted grade signal to DX, but if they respond and signal rays arrive at those angles, I will never hear them :(.

Lastly, 150 Feet height  was not the best in both the cases either. One can see deep nulls at some elevation angles with good %ge of signal arrivals. Most of the contesters have mono bander stacks just to overcome those deep nulls. Following is stack of two number of 3 element yagis at 90 and 120 feet.  See how it moves the nulls to right making space for desired angles.

Today, I feel I know many of these wonderful areas of propagation due to software such as HFTA, but handicapped to try the improvements. I am hoping that in the future, I can go to right places and put portable stations for contests!

Cheers
VU2XE Kiran


Disclaimer: As usual, this blog and its content is only based on my own personal experiments and observations. I share it for fun and in hope to kinder some curiosity. I am no expert in these areas. Sometimes, my conclusions may not be accurate. For accurate information you are suggested to look out for original sources and experts in these areas.

Multibander antenna and harmonic radiation thoughts

Desclaimer: Articles here are purely based my personal experiments and observations. Though i read lot of articles and books on my favorite subject of Antennas and Propagation, i am no expert in this field. If you are here looking for such accurate information, this blog may not be for you. Otherwise, hope you will enjoy reading these posts and probably try some techniques yourself!

I have been using HF multibander for many years now. My first multibander 40-10m antenna at Mumbai QTH involved simple inverted Vee with single feeder at around 20ft above the apartment terrace. It worked very well giving hours of fun on the band.

I started using tuned magnetic loop for QRP digital modes when I traveled within US. It was simply amazing experience using loops.

When I moved to Bangalore in 2011, my first comeback antenna was Hex beam. It is awesomely portable, and gave value for every bit i spent. It was my sole antenna for couple of years with some experimental wire delta loops, dipole and verticals on the side. Currently, I have Spiderbeam antenna which is another dB upgrade to my station for sure!.

All these times i was not much having thoughts around monoband antennas other than my 40mtr vertical. I had not even considered putting up any serious yagis due to apartment living. Reading a lot about other contest stations around the world, i was wondering why they normally have mono bander stacks. One obvious reason is for stacking antennas with optimal height distances and pattern uniformity. Second reason, i am sure these multi stations aim is for reducing harmonic  radiation.

This second aspect, never caught my attention till now. Here is what happens to typical station transmitting with solid state amplifier. Suppose amplifier's LPF section is not working, and fundamental on 40mtr is around 400Watts, second harmonic is 40dB down and third is only 10dB down. Refer https://www.w6pql.com/a_1.5kw_lpf_for_160-6m.htm
15mtr band will see 40W signal for 400W. Without LPF between amp and multiband antenna 40 to 10mtr fan dipole for example, will transmit both 400W fundamental signal and also 40W harmonic signal will be transmitted on the air. This power is more than sufficient to cause QRM. It just sucks!.

Currently my amplifier has LPF board which suppresses the harmonics to greater than -50 dB. That is to teen milliwatt level which brings signals into safe zone. Now going back to multiband antenna again assuming that there was no harmonic suppression, with yagi of 10dB gain, 40W harmonic would sound like 400W signal simulcasting on harmonic band. With resonant monobander this problem is eliminated. In reverse direction it is true for receiving as well, resonant monobander acts like pre selector eliminating any front end related issues and IMD. Whereas, multi bander keeps gate open for all signals resonant on those bands.

This topic started to make me think some field antennas tried in the past by me such as fan verticals and fan inverted Vee, may not be right choice during the contests or in multi station activation.
A point to ponder further and probably test sometime!

Cheers
Kiran VU2XE

Lowband HF experiments near coastal river delta

Not all hams have similar aspirations of field days. Some go to outdoors for pure fun and relaxation, some to enjoy nature, some to learn about disaster communications using portable setup and some more like us may go in search of low noise heavens!

Many mighty rivers merge to Arabian sea in this region

Hailing from Dakshina Kannada district, I grew up traversing small bridges each day while making trips to school, college and later travelling up the coast from Mangalore till Kundapura etc. The mere scenic beauty of coconut plantations on the banks of these rivers always captivated my imagination. 

After my interest in Ham radio started to grow, I had started dreaming about operating from such locations. As you approach the coast river water draws sea water making it saline. Unlike some backwaters of Kerala, here the water is mostly saline with high PH values except for monsoon season (June - August). Land in these areas are salt soaked and highly conductive. As a ham, tell me if it does not ring your brain hi hi!

Little bit of planning:
In recent years from my Bangalore QTH I had done some decent operations on higher bands. But with Sunspots going down, 40mtr and lower band operation caught my curiosity. But playing with 80mtr and 160mtr from apartment terrace is much less feasible and one would have to be satisfied with the compromises. 

Around the time when VU7T plan was going on with larger team, I wanted to go to a low noise area within VU with single simple objective of having two or three bands to operate at night. When my friend VU3NXI Siddhu got to know of my intention, he caught on to it. I was bit nervous as he was not much on CW and I would go only with CW limited operation. Anyways, I started checking on various websites and zeroed on location based on Google Earth's images and its immediate elevation characteristics. There are many hotels on the coast, but I wanted to go to individual lonely place where they can give entire property access and with no nearby hawkers. I found one small house near river delta point just north of Udupi town. I then had few rounds of information exchange with the owner explaining the purpose of our stay and activities we want to do. Once they got convinced, booked their property on airbnb website.

We applied for temporary QTH change permission for our respective calls. Thanks to WPC, got the permission within 3 weeks without any followups!. Since we had clear objective of low band, we never set goals on QSO counts, but spent time on antennas to be made. N6RK loop (project from VU Contest group) was one antenna for RX and

Terminated RX Delta loop balun 9:1

second antenna I had in mind was terminated delta loop. For verticals we carried 12mtr spider pole and thought of making one vertical and two inverted Ls. The moment I made this field trip news public, many started asking us to carry amplifier and bigger antennas. Come on guys!, this is my first trip to unknown place and that too first experience with low bands. 

I had planned for weekend of ARRL 160mtr contest as some low band operators would have prepared their antennas and winter time propagation advantage on our side. Other than taking down my own station, getting some extra length of coax and some wires cut for 160, 80 and 40 there was not much fancy thing required for us. 

At the location:
Myself and Siddhu reached the place just north of Udupi by overnight bus.  Upon reaching the place we realized that we might be in dreamland as we did not see any HT electrical lines, nor densely populated places in 2-3 kms. We also realized that we should go higher abandoning 12mtr pole to 65-70ft tall coconut trees. We made a quick call to the host and fortunately tree climber was available that day who rushed to our place. 

Our impromptu Antenna setup 3 band trap less full size !

Couple of years ago, i had purchased a large spool of nylon fishing chord from Decathlon store which came much handy. We asked the climber to tie one rope to the tree and drop nylon rope similar to pulley lift. He did the job perfect within 15 minutes. As hams we have to apply all our creative juices to the job done and doing something different and experimenting was exact reason we had this field trip. So we did not pay much attention to whether something should be as per books or no, but we just applied our thoughts. We didn't knew exact height of the tree so we first lifted 80m element and found that around 5 ft of wire would be left after going straight. Pulled that back and now along with 80m (with upper string attached ~5ft lower, we attached 160mtr with center of the wire around 5 feet length away from the main rope. We did not attempt to test SWR yet. We pulled the setup back again and then attached 40mtr element which would hang halfway mark. Few pull up and down we could get symmetry between ropes when we pulled the ends away from center. We then attached homemade choke (mix31 with RG142)at the base of element and pulled elements apart so that it is spaced. For radials we had two for 40, one each for higher bands. Which were run on adjacent to coconut trees at 5-6 feet height. SWR tests showed sharp dips to 1.1 range on all bands near CW region. Aligning the radials would impact SWR with raise in ground loss as we couple of times dropped the radials and saw SWR shooting up above 10. With vertical exercise now completed we went to relish local food at restaurant around 5 kms in nearest town to us.

After lunch we put N6RK loop just around 2ft above ground (next day we raised this to 4 feet above ground and noticed improvement in reception as lot) and delta loop using 12mtr spider pole we had carried. We also had a quick A - B switch done there for playing with loops. 

We were stunned with noise levels. Though I have been to VU4 and VU7, I could not believe signals we were hearing on mainland. Most of the time we just resorted to magical SWLing than CQing!. City

VU2XE and VU3NXI - grey line DX

life had snatched away all our ears and this was really like applying balm soothers. We also found that N6RK loop though having lesser gain, had very low noise and signals appeared clearer. Though signals were very strong on 40mtr, we wanted to make most of our time on 160 and 80mtr. On the first day, I was very tired after long journey and antenna work, so Siddhu operated radio most of time after midnight. Second day, we spent on re adjusting location of the loop to right on the edge of water line and raising delta loop height. That night I also entered lowband chat room as there was good internet available. Each QSO I made on 80mtr had a feeling similar to ATNO!. Hams started asking me to go down to 160mtr after 12:30am IST ( 20UTC). And I did so to realise that good signals come by that time onward. Some NA hams were also getting us well, but I could not hear them.  Keeping watch on morning grey-line approaching fast over the location, I heard a weak K signal. Just seconds away that signal was stronger like 539 -549. It was KA1R the only station we had from NA on 160mtr. He must have studied our google location and was on right time to give us a call. Greyline was so quick that we could not hear any others from NA. 

Boat to cross small hop!

Just after this we dismantled in rush to catch our bus back to Bangalore. Our experiments on the field was most gratifying experience. DXpedition type of goals would not have allowed us to think through, reflect and apply some raw ideas which worked for us in this trip. 

Malpe beach. Launch pad for IOTA  AS - 096 St, Mary's Island

We worked few VU hams such as 
VU2CDP, VU2CPL, VU2ABS and VU2BGS on low bands. We thank them and global top band DXers for being on air/chat rooms with us to help listening, VU3NXI Siddhu for accompanying me and experiencing/sharing joy of the practical aspects of field operation.

Zone vs Band Statistics

So.. what are you thinking now?... Go places! with bit of planning, lot of fun awaiting for sure!

VU2XE
Kiran

Some videos showing our simple antenna setup:

Following is diversity reception audio(use head phone to listen to stereo from 80mtr yagi in one and 1000ft beverage in other) clip shared by VE6WZ. Unfortunately I did not hear him :(

40mtr Vertical project

Here is new edition to my station... Homebrewed 40m vertical. Nothing fancy, just aluminium sections clamped to specially designed tilt base.

Base plate, made with 1.5mm aluminium sheet.

Tilting mechanism designed by me
and VU2MUD

closeup of vertical

Vertical on our terrace

Construction story to follow on ARSI HRN magazine soon!

VU2XE

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