Saturday, December 18, 2021

Protect connectors with this simple Hack!

 Amateur operators use many type of connectors in the shack and in the field. One of the most common connector I use is UHF. When they are used in outdoor transmission lines, we normally waterproof them using rubber tapes, insulation tapes etc. While they are not in use, if they are left outside in garage or workshop, dust/moisture ingress will deteriorate their performance over time. Often, we should use contact cleaners before taking them out for use.

In the past, I have used plastic caps (MX in India sometime comes with such caps) and metal threaded dust caps as well. But, they are hard to find in India. I wanted a easy solution for making quick n reusable protection for many UHF connectors I had in my box. This is a problem while carrying devices to portable locations as well, especially unprotected PL259 connectors take hit when uncoiling coaxes. 

Here is what I came up with available heat shrink sleeves. Yes they are not good as threaded caps, but 

1) Keeps connectors from sand, dust, water ingress

2) Reduces wastage of insulation tape during transport or uncoiling coax

3) Can be quickly made in the field too!



73s 

VU2XE




Wednesday, December 1, 2021

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


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