Receive antenna success

After going through the effort to install a new NA Beverage (see previous posts), I was nervous the first time I listened with it. Turns out, I needed not to worry. The first station I listened to was VE1ZZ - the most difficult area in NA to hear on 160 except for VO1. He was peaking 559. Better yet, I had no copy on him at all on the old NA Beverage, the one I have used for the last 18 months.

I can tell that there is some feed line loss - this antenna seems to have less gain - but there is no hint of line noise, which is constantly present on the old antenna, sometimes S2. The noise floor is significantly lower - by 12-18dB - but signals are about the same strength.

Today I disconnected the old NA Beverage and reconnected the SA wire. I will probably take down the old NA Beverage and use it for a new receive antenna toward New Zealand - a direction which can be somewhat difficult for me to copy currently. A 160 degree heading should cover ZL, east VK, and EU long path quite nicely.

Before then I need to build a new remote coax switch capable of switching more than two antennas. I’m working on a schematic now built around a LM3914 chip and a bunch of 78XX DC regulators. I should be able to design something that can switch 5 antennas remotely with only the feed line - no control wires.

The station is set up now for CQWW DX RTTY this weekend.

gopr5965

I have RTTY working on both radios so I should be SO2R ready (two CPUs, stations interlocked via PTT lines and W6NL designed lockout box using NTE2357 devices). If you’re wondering what the two feed lines are that run under the amps; these have BNC quick-disconnects so I can manually insert bandpass filters. Not much of my station is automated.

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Posted under Uncategorized

This post was written by admin on September 27, 2012

Walking Beverages

I generally have to walk all my Beverages about once a month.  If I don’t the growth becomes overwhelming.  It may not be true, but I’ve felt that wet vines, branches, and leaves tend to cause some attenuation if they contact the uninsulated wire in too many places.  Walking the antennas regularly allows me to try to keep the jungle at bay, before it becomes a huge clearing project.

Yesterday, while working on clearing the route for my soon-to-be new NA Beverage, I brought my GoPro camera.  Once I finished clearing a path to what will be the termination point, I turned it on and walked back along the length of the new trail I had made.  This video will give you an idea of what it’s like to walk in the jungle here on Northern Guam.  The area is very typical for what you find in the northern forest, however I chose a route that was less heavily overgrown than many other areas in an attempt to make my job clearing easier.

You may notice that I am walking slowly.  This is on purpose, to keep from tripping over vines, roots, and rocks laying on the ground.  Additionally, you will notice that the jungle is absolutely silent.  There are no birds in the jungle, which is very much in contrast to my housing area where birds can be heard chirping all day long.  Why?  Because of the brown tree snake.  You will never find one in the jungle, but they are everywhere, masters of disguise hiding in the tree tops during the day.  The birds have migrated out of the forest and into trees on base, because it is protected from snakes by a barrier of snake traps.  It can be eerily silent in the jungle, and I’ve often been startled by the quick explosion of noise which occurs when I stumble into an area where pigs have bedded down for the day, as they crash through the jungle running away.

By clicking on the Youtube icon at the bottom right of the imbedded video, you can watch a higher resolution version in a new window.

Posted under Amateur Radio

This post was written by admin on September 17, 2012

New Beverage project

From Guam, there are two primary directions for radio: NW for Europe and NE for North America. I have two long (~1000ft) single wire Beverage receive antennas, one toward each population area. My European (NW) Beverage hears incredibly well, as there are no noise sources for 1500 miles in that direction, only jungle and ocean. Unfortunately, I suffer some noise in the North American direction on 160m, usually hovering about S2. This noise only affects Top Band for some reason, and the source is line noise from civilization about 1 mile distant in that direction. At times, the noise has made it difficult to copy the next layer down of NA stations calling on 160. I’ve decided to try to mitigate the noise by laying out a new Beverage for NA.

Existing NA Beverage

Existing NA Beverage

The existing wire is just over 1000ft long and is pointed at 046 degrees - the center of the continental United States. It has served me well, allowing me to complete 160m WAS, but it is still noisier than I would like. This antenna is already version 2.0 of my NA receive wire, located further west (deeper in the jungle) from the original version 1.0 which was even noisier but closer to the road and power lines.

The new route is significantly further west and deeper in the jungle. The feed point is about 1300 feet from my house, and will be fed by quad-shielded RG-6. Over the past week, I have taken time to mark out the route, clearing a path along the way.

New NA Beverage route

New NA Beverage route

I brought my new Nexus 7 tablet which comes with a GPS receiver and was able to plot my track with Google Earth.

The new route is just under 1000ft in length, and pointed just about 030. I did this on purpose, as this direction is oblique to the noise source which is centered more in a 060 heading. I hope this helps null the QRN significantly. This is also the direct heading for W1/2/3, the most difficult region of NA to work from here.

When working in the jungle, I keep covered up from head to toe. This is to keep the spiders, spider webs, mosquitoes, and sharp leaves off my skin. Bug repellent barely works, and after 5 minutes, sweat has washed it off and the mosquitoes are clouding around me again. An old T-shirt covering my head keeps them at bay.

Jungle wear

Jungle wear

I wear a white, heavy duty long sleeve shirt with gloves. The white is for visibility because I know a couple people who do hunt in an area adjacent to where my antennas are located. I wear an old pair of USCG ODU pants which protect me from stickers and other things that scratch. The head-to-toe covering helps protect me from wasps as well.

Can you spot the hornet nest?

Can you spot the hornet nest?

The smaller “boonie wasps” are very aggressive and painful, but at least for me, their sting wears off after about an hour. The larger hornets, on the other hand, are less aggressive but pack a powerful punch. A sting from one of these is like getting hit by a line drive baseball, and it hurts for well over a week. They also have a habit of building nests in ferns, about 1-2ft above the ground where they are impossible to see until it is too late. Today I ran into one of those nests, but fortunately did not get stung. I beat the brush ahead of me with a 6ft piece of aluminum tubing to try to give myself some advance warning instead of stepping right into them.

Close up of the hornet nest.  These guys are not aggressive but have a very powerful sting if their nest is disturbed

Close up of the hornet nest. These guys are not aggressive but have a very powerful sting if their nest is disturbed

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Posted under Amateur Radio

This post was written by admin on September 16, 2012

GoPro Hero2

I picked up a new toy this week - a GoPro Hero2 camera. The first thing I did is hook it to a long pole and take a bird’s eye photo of my Spiderbeam.

Looking north from about 50ft:

11

The Beverage RX antennas are all in the jungle in the distance. You can make out the 40m vertical to the bottom left, and also the 5el 6M beam hanging from a coconut tree to the right.

I’m going to have fun with this new toy!

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Posted under Amateur Radio

This post was written by admin on September 14, 2012

New 80/160m antenna

My original 80/160m antenna has served me well since transferring here to Guam. It was configured with balanced “window line” as an inverted L on 80 and a top loaded TEE vertical on 160m. The top was at about 58ft, the highest I could go with the current mast configuration.

The problem was that the two top loading wires were not 180 degrees out from each other. They were more of a 120 degree separation, because of where the coconut tree end supports were located. This pulled the mast to one side, and the prevailing trade winds pushed it over even more. I attempted to back guy the mast, but since I had threaded the mast through the center of the tree, I could not get the support to the top and eventually the mast started to bend.

Eventually it got so bad that my kids named it the “Banantenna”.

Banantenna (aka banana-tenna)

Banantenna (aka banana-tenna)

Every year I like to try to improve the antenna system. This year, the project was obvious: replace the Banantenna.

The new mast is now taller, just under 70ft. It is much stronger. The top section is a 25ft long piece of bamboo, which is strong and plentiful. It is lashed to a section of aluminum boom, which in turn is telescoped into a 20ft piece of 2″ water pipe. The new mast is routed through the tree differently, and is much easier to put up and take down. This is important, especially during typhoon season.

Gone is the 80m inverted L and 160m TEE. The new antenna is a full 1/4 wavelength high vertical for 80m, which is top loaded for 160 with three top loading wires. The top loading wires are staggered 120 degrees and serve also to support the mast in the wind. Again, I used 450 ohm balanced “window” line. At the feed point, both wires are joined. At the far end, one simply terminates (this side is the 80m vertical), the other continues to the top support and three top loading wires (160m top loaded vertical). Essentially, I have two parallel verticals, separated by one inch (the window line). They share the same feed and radials.

New 80/160m vertical and mast

New 80/160m vertical and mast

Looking up, you can see the bamboo mast section and balanced feedline radiator

Looking up, you can see the bamboo mast section and balanced feedline radiator

Three top loading wires

Three top loading wires

The feed point has not changed. I still use a remote vacuum relay to switch a hairpin coil across the feed point when on 160m, this serves to match the low impedance 160m antenna to the 50 ohm transmitter. The impedance on 80m is high enough to be fed directly without matching.

Feed point configuration

Feed point configuration

The new antenna does seem to work better than the older version. Stateside stations seem to be hearing me better than previously on 160m.

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Posted under Uncategorized

This post was written by admin on September 11, 2012