Short Wave listening

[scrubjaysnest]

ain't what it used to be.
Dug out my old Radio Shack DX 390 (aka Sangean ATS 818) and cleaned it up.
Still works great but so sad to see so many of the SW broadcast stations no longer on the air. Sign of the times I guess.

Don't know how much interest there is in this subject, but thought I'd get it started. There are a few members that are Ham radio operators so I'm sure they have some insights.

Yesterday, I started working out a portable antenna system to fit the TM. The basic idea is light weight and don't add a lot of time to the set up/break camp process. With this in mind the antenna needs to be easy to get to so it can be attached to the shells as they are opened up. This of coarse limits the antenna length with a resulting loss of performance (still better then the telescoping antenna that comes with most portable AM/FM/SW radios today). Basic antenna theory for the short wave (sw) or High Frequency (HF) bands is the bigger the better.

Normally the wire size used is 14 or 18 AWG to support the wire when suspended. But since we aren't making an antenna of 100 plus feet smaller wire can be used. Since I had a spool of insulated 20 AWG wire and 20 to 30 feet is a reasonable compromise on the bigger is better thing that is what I used. Cut it to the TM length and soldered it to a connector that fits the DX 390 aux ant (antenna) jack. Since the ant will perform better with a counter poise, another wire that parallels the ant wire but is near ground level, I added another short wire to the ground side of the connector with an alligator clip to connect to the TM frame, instant counter poise! For storing the ant just made rolls up on the wire spool.

Performance was improved allowing me to receive a BBC broadcast from west Africa on 11810 MHz which I was unable to do with the telescoping ant. The BBC by the way no longer broadcasts to North America.

Things to beware of, for the DX 390 it is positive ground so when using an external power source from the TM batteries you need to make sure 12 VDC to 6VDC converter is fully isolated if you plan to connect to the TM frame as I did.
Over head power lines are a killer, noise source, plus yourself if you come in contact. So TM position needs to be watched for what is over head and you may want to limit how high above the TM the ant mounts.

Next to figure out an ant mounting system at which time I'll add some pics.

[Padgett]

One of my other other hobbies...

[BrucePerens]

Not only are many shortwave stations off of the air, the noise is much worse because of computers. All digital logic generates noise. DSL lines use RF carriers which leak out of the wire (and RF leaks in as well, which is why some DSL is slower at night).

I had to move my antenna away from the house.

[wbmiller3]

In 1977 an early homebuilt PC generated so much RF noise that you could place an AM radio near it and run a program to play music on the radio. It being the summer of 1977, I still have a sound file of the Star Wars theme that we genned up.

The computer had no keyboard or display. Input was via toggling front panel switches and output was LEDs on the front panel. There was no persistent memory of any kind - if you tripped over the power cord all your work was gone. We've come a long way.

[scrubjaysnest]

Originally Posted by wbmiller3

In 1977 an early homebuilt PC generated so much RF noise that you could place an AM radio near it and run a program to play music on the radio. It being the summer of 1977, I still have a sound file of the Star Wars theme that we genned up.

The computer had no keyboard or display. Input was via toggling front panel switches and output was LEDs on the front panel. There was no persistent memory of any kind - if you tripped over the power cord all your work was gone. We've come a long way.

Sounds like the computers we ran the power plant with; push buttons with lights so you knew if it was a zero or one.

[Padgett]

Light Emitting Diodes ? We had nixie tubes.

[scrubjaysnest]

a pirate station last night; the tongue in cheek ads were funny.
6.955 Mhz still seems to be a favorite frequency with the pirate radio group.