Monthly Archives: June 2015

More on a directional VHF antenna

Now thinking that a better choice over a Yagi for 2m is a Moxon. The Moxon has a few really positive attributes:

  • Reduced size – folded elements
  • 2 elements have approximately the same gain as a 3 element Yagi
  • Large Beam width and Front to Back ratio
  • Easy and cheap to build

For 2m the Moxon rectangle works out to about 29″x11″. Here are some EZNEC predications for such an antenna realized with #8 copper wire:

2015-06-30_12-52-332015-06-30_12-52-55

I am going to try an build this by making a frame out of 1/2″ PVC and then putting the #8 wire around it and holding it in place with zip ties. This should be a fun and inexpensive experiment for 2m

Start of Field Day 2015

This video says it all!

I just wonder where all these hams are the rest of the year….

VHF Yagi Ideas for Simplex Work

Some local hams have been experimenting with VHF simplex for communicating up and down the valley. The guy who usually leads these experiments is located in Brownsville and has his VHF vertical mounted on a 40 foot tower. He is able to communicate with other hams up and down the valley depending on the other hams configuration. I can communicate easily with him from my home QTH but I am deaf to all but one other local ham on simplex.

My VHF station is spartan at best. I use a 4W Baofeng handy talkie connected to a discone antenna that is up about 10 feet. I get no gain from the discone. This setup works real well for hitting the local repeater and for limited local simplex. I started thinking about the geographic location in respect to other stations in the valley and plotted the following map:

2015-06-30_7-16-07

My QTH in Brownsville is in the lower right hand side of the map. The Rio Grande River is the US-Mexico border and the Gulf of Mexico is to the East. To cover the valley I only need a Beam width of about 126°. I started thinking about building a 2 element yagi vertically oriented and came up with the following azimuth pattern using EZNEC:

2015-06-30_8-51-10

This antenna would give me a 133° beam width and a gain of 7.5dB over what I have now. My only concern is the rather low take off angle of the main lobe. Clearly the higher the better for this antenna but it looks like it would be a good starting point for experiments. Should be fairly simple to build from PVC and aluminum tubing. Will post more as I progress on actually building this.

ARRL Field Day 2015

Field day 2015 finally arrived today!

My original plan for today was to operate from my backyard and setup the homebrew Buddistick on 10m and the homebrew Buddipole on 20m. Instead I went portable to my dad’s house in Mercedes, TX and setup only the Buddistick on 20m. I used the FT-817ND on 5W with the auto tuner and on solar charged battery power.

Photo Jun 27, 12 21 55 PM

It took me about 30 minutes to get everything setup just taking my time to do so. I had about 20 minutes before 1800UTC so I made a few contacts as a radio check.  The Buddistick tuned up very nicely on the 20m band. Really didn’t need to use the tuner but found later that I could tune the antenna on 15m without changing the configuration! So I was able to work 15m and 20m without adjusting the antenna! The Mini60 is indispensible for work using the Homebrew Buddistick. Don’t leave home without your antenna analyzer.

Photo Jun 27, 12 21 40 PM

At 1800UTC the band came alive….so many signals many on the same frequency. I had never seen anything like this during a contest. 20m was instantly wall to wall but I still managed to make some of my first contacts of the day. I would scan from top to bottom of the band then switch over to 15m and do the same. 15m was busy but much easier to work as there was much less traffic. I operated off and on till about 0130UTC and logged 45 phone contacts on both bands.  I think that works out to a score of 475…not bad for a 1B battery station!

Overall really happy with the rig and antenna performance today. I had just a few stations have difficulty with my call and most got it right the first time. Just really hard to break through the strong adjacent signals. I probably will not work FD on Sunday but I am already thinking about how I will operate next year.

Mini60 Antenna Analyzer USB Port not Recognized

I was going to run some sweeps with the Mini60 antenna analyzer this morning and found Windows 7 (64-bit) trying to load up the FTDI drivers then failing to do so. This was very weird behavior given that I had used the Mini60 on this same machine just a couple of weeks ago. Messed with it a while then tried to hookup the Mini60 to a laptop I had used in the field and found the same thing was occurring. The mini60 had worked on these machines and now were not recognized.

Searching the internet I came to find that FTDI modified their drivers late last year to prevent them being used in devices using fake/counterfeit chipsets based on the FTDI design. Looking at the USB device ID’s on the MIni60 showed that indeed these were not genuine FTDI chipsets. This issue is pretty widespread and are used in many devices having USB to serial interfaces including Ardunio boards, CHIRP programming cables and generic USB to serial conversion cables.The new drivers are now included in the latest windows updates so when they are installed (either manually or in my case automatically) it prevent the device from using or installing the drivers.

There is a way around this as outlined here on Reddit. Basically you will need to uninstall the device, disable windows auto updates and then load an older driver. I did this and am now back in business.  I will now have to monitor windows updates manually and fully expect to have to repeat this procedure as new updates are made.

While I understand that FTDI is trying to protect their IP by doing this, it also puts hapless users in a very bad position. I don’t usually look under the hood of electronics hardware I buy to see if the components are genuine. I just want to buy something that works. Many hobbyist devices use the FTDI chipsets and many of those folks are now completely out of luck.

caveat emptor

Ham Radio in the Local News

KRGV Channel 5 covered South Texas District 15 ARES activities in their annual hurricane preparedness special “Facing the Fury”. You can view the piece related to ham radio by clicking here. You can catch my voice on my 2m HT about 47 seconds into the video.

Follow up to My SPI Balcony Operation

Haven’t had much chance to try HF from my condo balcony here in South Padre Island but I did manage to fire it up again this morning. The antenna and station deploy in about 5 minutes from my camera case GO-box.

Photo Jun 11, 10 30 49 AM

The antenna was deployed as before across the length of my balcony and then dropped over the side. I can tune up nicely on all bands 60m thru 10m. 6m would not tune at all though. The bands above 15m were pretty much dead this morning. 20M was the most active and I heard quite a few QSO’s in progress. All were stateside and I heard no DX stations. I did not have an opportunity to answer and call or break into a QSO in progress. I called CQ a few times with no takers. So I have decent reception and the antenna tunes but I have yet to make a contact. Here is the end fed antenna box sitting on my balcony rail:

Photo Jun 11, 10 30 59 AM

Portable operation in South Padre Island Condo

Setup the FT-817ND on the balcony of a 3rd floor condo on South Padre Island. Used an end feed antenna with a 33 foot wire stretched across the balcony rail and then dropped down along the side of the condo. Antenna tuned up well on all bands 80m-10m. Was able to receive quite a few stations but I did not work any of them. Will try again during the week and see if I have any better luck.

First test of my Homemade Buddipole

Finished and tested my homemade Buddipole this past weekend. I set it up for 20m operation which is full length whips (9.3 feet) and a 2.1uH coil and a two foot extension arm. The whole thing was mounted on an 8 foot painters pole that was extended to 16 feet for operation. When setup at 16 feet the antenna measured to be resonant at 14.32 MHz with an 1Mhz bandwidth of SWR less than 2.

Photo Jun 06, 12 06 59 PM (1)

Overall, I am pretty happy with the way it worked, I do have to work on setting the painters pole up better. I tried 23 feet full extension but it started to bend badly. Will have to work on best methods of setting the mast up as well as adjust the guy wire lengths.