My subscription to Life expired, but I still have a subscription to Mad.

Wednesday, September 30, 2015

Connecticut Radio History

Sourge: Bing Maps
Radio Historic West Peak in Meriden, Connecticut
Connecticut has a rich history when it comes to radio. Accordingly, the University of Hartford's radio station, WWUH, is now running a 10-part series, "Connecticut Radio Memories" that deals with various aspects of that history.

Dave Kaplan, WA1OUI, a former engineer at WTIC and current webmaster of the WTIC Alumni Site received permission to post the radio series on the Alumni Site (here).


Monday, September 28, 2015

Computer-Controlled Switch System

TASS (Totally Awesome Switch System) is a general purpose 8-port DC-150 MHz relay-based switch. The hardware is designed to be very generic, with an inexpensive processor such as an Arduino providing the system logic. Control is via USB, with Ethernet and other interfaces also available.

The TASS can be configured several ways, and multiple boards can be combined to create large switching systems. The TASS has many uses, from switching signal sources on a test bench or in a laboratory, to selecting receive antennas and filters in a ham or SWL station.

The TASS system has two boards:
  • The TASS-R relay board, which does the mechanics of signal switching and provides a very simple 10-pin interface.
  • The TASS-SHIELD board for use with an Arduino Mega 2560 microcontroller. The TASS-SHIELD allows up to four TASS-R boards to be controlled simultaneously.
Both boards are available now from TAPR as kits. They use through-hole parts and don't require any special assembly techniques.

The final component is open source software for the Arduino that acts as an interface between a host computer or other input system, and the switching hardware. The software is available for download from TAPR.

An introductory video is available here.

Software and documentation can be downloaded here.

You may order the TASS-R and TASS-SHIELD boards here.

Thursday, September 24, 2015

Taylor Swift and My KX3

In May, I bought an Elecraft KX3 radio kit with almost all the options at Hamvention. Out of stock in Dayton, Elecraft shipped the kit to me and it arrived about two weeks later.

After some confusion on my part about receiving some wrong hardware, I built the kit and as I wrote here, I initially thought the receiver was deaf. Elecraft came to the rescue and had me install the default configuration file because I probably messed up some settings that deafened the receiver.

As I wrote back in June, "the receiver came to life after loading the defaults," but despite what I wrote, I still thought that the receiver was not that receptive and not living up to its reputation.

My spouse and daughter went to Gillette Stadium to see Taylor Swift in concert on a Saturday evening in July, so I had the house to myself for a good hunk of the day and planned to use the time to install the 2-meter receiver in my KX3.

About 45 minutes into the process, I had to disconnect the cable that mated the HF antenna connector assembly to the automatic antenna tuner circuit board. Then I had to remove the automatic antenna tuner circuit board. 

After doing so, I noticed that the cable I had just disconnected seemed to flop around too easily. Examining the cable, I saw that only one strand of the stranded wire cable was actually connected to the HF antenna connector assembly! When I touched the cable, the remaining strand of wire broke. too.

I'm not sure what caused the cable problem. I may have broke it during the kit assembly, but I don't know how because I only had to deal with the cable briefly during assembly. It was not like I was moving it around a lot and weakening the solder joint.

Anyway, I closely examined what I needed to repair, but there was no way I could fix it. My eyesight isn't what it used to be and even with magnifying glasses, I was not sure where the cable was connected to the assembly. And even if I figured it out and soldered the cable to the assembly properly, the cable might now be too short to mate with the automatic antenna tuner circuit board. 

I called Elecraft Monday and explained my plight and they agreed to send me a new HF antenna connector assembly, which arrived a week later.

Meanwhile, serious family health issues required my attention and there was little time for radio throughout most of August. The health issue was resolved two weeks ago and after the dust settled, I hunkered down and began working on the KX3 again.

Monday evening, I replaced the HF antenna connector assembly and Tuesday evening, I finished installing the 2-meter transverter. After buttoning up the radio, I connected it to my 40-meter dipole, powered it on and held my breath. 

The radio came to life tuned to WTIC (1080 kc) and the Red Sox game was in progress. I immediately noticed that the receiver sounded a whole lot better than before the Taylor Swift concert.

I tuned up and down the AM band and could hear one or more stations on most of the AM channels, which was not the case before Ms. Swift took the stage. I switched to the HF ham bands and the receiver seemed much more sensitive than before.

Now I was worried about the transmitter. Was it stressed transmitting into that single strand of wire? I inserted my HF SWR/watt meter checked the transmitter's output and it did not seem worse for wear with the meter measuring 10 watts more or less.

I am not an engineer, just a ham who has been around the band a few times, so I don't know if the single strand of wire was the cause of the receiver's deafness. Would the receiver care if it was connected to the antenna via a single strand of wire or multiple strands of wire? My guess is not and perhaps there were other issues with the HF antenna connector assembly.

Anyway, I am very happy with the KX3 now and plan to build the PX3 on Saturday when my spouse and daughter go to the Big E to see Kansas in concert.

Tuesday, September 22, 2015

DXing without the Red Sox

Monday afternoon, I received word that WTIC (1080 kc) would go off the air for transmitter maintenance after the Boston Red Sox game.

I live 12 miles line-of-sight from WTIC's transmitter and its 50,000 watts 24/7 have made it impossible for me to hear anything but WTIC on 1080. So I planned to stay up for the down-time despite having to get up at 5 AM to go to work the next day.

As luck would have it, the Red Sox game started late and was almost four hours in length ending around 11:15 PM. The post game show ended about 11:45, when they finally pulled the plug at WTIC.

I listened intently to 1080 and could only detect one station way down in the mud playing MOR tunes that I did not recognize. When an announcer came on, he was unintelligible, but I hung on hoping that the signal would get stronger.

After about 10 minutes of down-time, WTIC came back on the air briefly, then went off again. About a minute later, it came on again.

After a minute or two, I assumed they were staying on the air for good, so I gave up and went to bed with nothing new in the log.

Sunday, September 20, 2015

DXing with the Red Sox

Around sunset Saturday evening, I tuned across the AM band with my C.Crane CC Skywave receiver looking for broadcasts of the Boston Red Sox baseball game. Being a long-time Red Sox fan, I am very familiar with the voices of the Red Sox radio announcers, so I was able to identify broadcasts of the games even if the signal was down in the mud and/or competing with other radio stations on the same frequency. And as soon as I heard a game, I could identify the station quickly by referring to the list of radio stations on the Red Sox Radio Network (there are only a couple of stations on the same frequency).

I heard the game on a half dozen stations and two of them were new loggings:

  • WDEV on 550 kc transmitting 5 kW 186 miles to my north in Waterbury, Vermont at 2242 UTC.
  • WGHM on 900 kc transmitting 910 watts 108 miles to my north-northeast in Nashua, New Hampshire at 2252 UTC.

About 20 minutes later, I logged yet another station on the Bloomberg Radio Network:

  • WTWK on 1070 kc transmitting 5 kW 205 miles to my north in Plattsburgh, New York at 2317 UTC.