Thursday, May 1, 2014

6 Meter Homebrew Yagi Tunes Up! Hooray!

6-meter yagi from below on mast
The 6-meter Yagi at full height
With the impetus of several suggestions from the QRZ Forums Antennas group, I made a great leap forward in tuning up the homebrew 6-meter Yagi. First things first, I replaced the test cable to the AA-54, which had an intermittent short or open in one connector. I made a longer cable so that I could step out of the antenna's immediate shadow and used bigger ferrites for the choke on the cable. While I was waiting for the PL-259 to cool down, I made a quickie 5 turns coax choke on a 3" form too.

I discarded the few turns through a 2" ferrite choke on the antenna feed line and inserted the 3" choke. Already the disparity between the SWR R/X readings on each end of the feed line was vastly reduced. I went back to adjusting the gamma match again and when I had it to an acceptable range, I decided to pull up the antenna mast to full height, which I can do single-handedly thanks to my counterweights at the bottom of the mast.

Wednesday, April 30, 2014

Need Help Tuning 6 Meter Yagi

I'm trying to dip my toes into VHF-land starting with six meters. I've built a 3-element Yagi, plumber's delight style with a gamma match and it's now sitting on the mast at about 6 feet off the ground.

6 meter Yagi at six feet elevation for testing
In testing position (please disregard that funky gamma clamp)

The half-inch aluminum elements were cut to a calculated length for 50.124 MHz and it's not far off in the test position. Trouble is, though I can tune it fine at the antenna, at the other end of about 100 feet of RG-8 PE core coax, the readings are way off, though there is a distinctive dip (actually two).

Friday, April 4, 2014

Hand Delivered QSL Cards from UX5UO and A New Straight Key from Ukraine

Last year, my elmer and good friend, Dan Keefe W6WU (ex-KS6Z, K6FFF), became a silent key. I very much miss our regular email exchanges that included his stories about his family (one of whom was U.S. Labor Sec'y, his political activities, and his own tales of being a Marine Sgt. who served in Korea at the Battle of Chosin Reservoir. He was a remarkable self-made millionaire several times over who also personally brought food to the homeless and ran his own Veterans rehab program from his home, teaching them carprentry skills even while his health was failing.

He was also my QSL manager. As I have not been active lately, however, that hasn't been much of a problem. I figured I better get some new cards, though, since it would be difficult to retrieve the set Dan had been keeping.

QSL cards and the B12 Soviet-era CW key
My new QSL cards and the B12 Soviet-era CW key


Friday, March 21, 2014

One Ham's Experience Obtaining A Reciprocal Permit in Costa Rica

A little over a year ago, the new primary Costa Rica government agency in charge of telecommunications regulation, SUTEL, came out with regulations of a sort for Costa Rican hams and foreigners wishing to operate from TI-Land. I gave an overview of those new ham regulations plus links to the manual (in Spanish) and the required forms to fill out (also in Spanish) in a previous posting.


Costa Rica SUTEL hands controlling marionette stringsThe first of several hams to contact me for assistance in obtaining a permit was Brian, VE3BWP. Besides trying to understand who to contact and how to fill out the forms (Brian doesn't speak Spanish), the main problem was that the regs say you must appear in person in San José and Brian's itinerary put them nowhere near the capital.


Remarkably, they accomodated his situation such that his operating permit was waiting for him at his hotel in Guanacaste! Below I've summarized the process that Brian went through and include email addresses of key contacts so perhaps the next ham wanting to obtain a permit will have an easier time of it.

Saturday, August 3, 2013

Costa Rica Call Sign Prefixes and Foreign Operating Requirements

Costa Rica's Call Sign Prefixes

Every once in a while, a radio amateur contacts me about the rules for foreign operators, which leads to the question of which call sign prefix they should use for their final destination. I don't have them memorized, they are hard to find on the Internets and I can never find a file showing them on whatever computer I'm using. So long as I can remember that I put it here, I can access it quickly and send the link to others.

Costa Rican mainland amateur radio call sign prefixes
The seven Costa Rica mainland call sign prefixes. TI9 is Cocos Island. Prefixes may start also with TE.
The new SUTEL radio regulations that I wrote about previously are continuing to be fleshed out. They are silent about the use of TI0 or TI1, but I assume those are reserved for clubs or special events. The latest link to Costa Rica's Amateur and CB radio regulations is here.

Cocos Island - Rare DX and Great Scuba Diving

TI9 is Cocos Island, which is uninhabited except for park rangers. By the way, why such a small country needs all these different prefixes is beyond me.

 It's a dream of mine to operate from Cocos Island someday. My pile-up skills may never be adequate for manning a station at that rare DX however. I can imagine the grumbling by DX spotters already, hihi.

Additionally, it's a logistical difficulty to operate from there because visitors are not allowed to stay overnight and it's a 340 mile boat trip from Costa Rica's Pacific shore. Perhaps one could operate from a boat anchored off the island. Even if I could not manage to operate from there, the diving is supposed to be superb. Cocos Island makes worldwide top ten lists regularly for the best scuba diving destinations.

Sunday, July 28, 2013

Final Modifications to My 20 Meter Extended Double Zepp


Nice sunrise, eh? But, wait, what is that funny wire with holes in it at the top of the photo? Well, actually, that is the feed line from my VK2ABQ that sits on a mast at the side of the house, but before I go there in a follow-on post, allow me to digress and return to my EDZ modification that I mentioned previously. As you'll see, the two antennas, though not literally linked to one another, are connected virtually by the new "electrician's nightmare" I have created.

Recall that before I tackle the craziness of the dual element 10 meter EDZ, I wanted to complete a mod to the existing 20 meter EDZ I have in the air, which consists of two parts: 1) add series capacitors to each leg to bring down the SWR curve across the bands (40 to 10 meters), and 2) ditch the coax from the EDZ tuning stub so that I have window line all the way to the station.

One of the caps, made from RG-8/U coax and sealed 8 ways to Sunday, is pictured to the right in place at about 24' in from the far end of one leg of the EDZ. I used 4nec2 to model the effects of placing the caps at different (but equal) locations along the wire legs and as in all things multi-band one must choose among a number of compromise scenarios. For this compromise, I optimized the pattern for 17 meters, since it came out with 10.77 dBi, higher than I could get on 20 meters. The caps essentially turned the antenna into a 17 meter EDZ and I lost about a dB and a half on 20 meters (but gained some beam width). 


Homebrew Ladder Line for my 200 Foot All-band Doublet

Drilling the Zareba insulators for 14 AWG wire
Drilling the Zareba insulators for 14 AWG wire
After my last post, there was still another day and a half of trimming trees to get a clear path for the doublet. I cut or trimmed at least twice what I thought I was going to when I started, which came to least three pick-up loads of trimmings. It was difficult work to say the least, running up and down rough terrain and tending to the hoists at each end of the antenna, which is about 100 meters long including the support ropes. Finally, Saturday, the rope and wire had a clear shot and I was able to pull it all the way up in the clear. 

In the middle of that, I took a break to start making the homebrew ladder-line with which I would feed the doublet. 


Back of the Zareba fence insulators package
Back of Zareba Package

As I'd mentioned in the previous posting, I ordered some Zareba (which I always remember as Zebra) fin insulators, a tip I'd picked up on an eHam page. These are small, lightweight, made from UV-stabilized polyethylene and just 10 cm long. Perfect. They come in packages of 50 for $4. I set up a quick jig on my drill press and made holes on each end 2 mm wider than the insulated 14 AWG solid conductor copper house wire I would use for the feed-line. Center to center the holes are 86 mm apart.



Sunday, April 28, 2013

Ham Radio Wallpaper from 2012 ARRL DX Contest

One year plus about a month's delay in our usual mail forwarding scheme it took for my ARRL DX CW award certificate to arrive! I'd been wondering if I was supposed to make a separate application for the award in addition to having submitted my log.

At that time, I'd racked up over 600 Q's and calculated a max score north of 96,000, all on 40 meters. I didn't learn until later that I needn't have busted my buns quite so hard, since it turned out I was the only participant in my category from Costa Rica! HI HI! A single QSO would have won me the certificate.

2012 CW ARRL DX Award certificate
2012 ARRL DX Award for Single-Band (40M)
No regrets, there, however. It was an experience unlike any I'd had before, working pile-up after pile-up, which tested my endurance (and the patience of those whose calls I had trouble decoding) and improved my skills. Always room for more improvement, of course. One area might be to reduce dups as you can see there's quite a difference in points between my estimate and the 85K I actually received.

I might have tried my hand at it again this year, but the contest snuck up on me before I knew it, so I didn't have time to prepare. Plenty of other contests throughout the year, though, at which I'd like to dip my paddles into.
Related Posts Plugin for WordPress, Blogger...