mike.chambers

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All blog posts have been migrated to the new site.

New version of ShortBoard .90

I have just posted a new version of ShortBoard, the Mac OS X application for searching for OS X broadcasts and schedules. This release adds the ability to add a broadcast to iCal so you can be reminded before the broadcast begins.

You can find all of the information, as well as download the application from here.

Resources for Learning Cocoa

Ive gotten a couple of questions lately from people asking what resources I use to learn Cocoa. I figured I would make a quick post, and list them:

Cocoa Programming for Mac(R) OS X (3rd Edition) - Aaron Hillegass

This is probably the best single resource if you want to just jump in and get started. It covers enough of the basics of Objective-C to get your going.

ShortBoard Shortwave App for Mac (v.85)

I have just upload a new Mac / Cocoa app I have been working on called ShortBoard. It is a simple app that loads shortwave broadcasts schedules from Prime Time Shortwave, and makes it easy to view, sort and filter them.

This is just a first release, and I am planning to continue to play around with it and add features (im using it to learn Cocoa).

You can find more information, as well as download the app from here.

Reopening an NSWindow once it has been closed

Unlike on Windows, the convention on Mac is that when the main application Window is closed, the application does not exit (although there are exception to this). If you are working on a Document based application, the functionality to open a new window is built in (just open a new document), however for a non-Document based Cocoa application, you have to implement this functionality yourself, which is pretty simple. First, you have to tell the window (NSWindow) to only hide itself when it is closed, and not also release itself.

URL Encoding with Objective-C and Cocoa

I have been teaching myself Objective-C and Cocoa (in part so I can build native iPhone / iTouch apps), and have been working on a simple command line application named "turl". This basically provides a command-line interface to url shortening services such as tinyurl.com and urltea.com.

Anyways, I ran into an issue where a specific URL was not being created correctly. It turns out, it was because I was not url encoding the url before sending it to the api. No problem I thought, I'll just url encode it. However, after much searching, I found that Cocoa didn't really provide a url encode API. I did find find a couple of possible solutions that used other APIs, but I could not get either one to work for me, and it didn't appear that they were made specifically to URL encode urls.

So, I finally decided to make my own and figured I would post it here in case anyone else needs to use such an API.

Antenna Getting Better

Well, I am slowly but surely making progress with my antenna. I have been having a lot of trouble with RF interference from my random wire antenna. I ran a shielded COAX feed to it, which I grounded, but reception was horrible.

Well, this weekend, I went back up the hill, and made some modifications to try and get a better ground. I also grounded the end of the COAX going into the radio. This second step seemed to make a noticeable improvement to the signal quality (although there is still a lot of interference). I was able to pick up some broadcasts I hadn't picked up before:

• 11735 kHz 0118 - 0122 UTC (Jan 14, 2007). Voice of Korea. SIO 222. This is the first time I have picked it up this early in the night
• 9675 kHz 0456 - 0505 UTC Radio Exterior de Espana. SIO 433. (via Costa Rica). News in Spanish.

My next step is to try to get a copper bar for the antenna ground (just have a small metal nail right now), as well as use a balum (need to read up on these some more).

Too much interference? Get in the car

Well, I have been pretty frustrated for the past week or so, as I have realized that there is just too much RF and electrical interference in my house. It is making shortwave listening difficult. Some of the interference is from my house (electrical system is really noisy), and some is from the neighbors.

As I posted earlier, I put up a long wire antenna, and this drastically improved my signal strength. However, it lead to two problems. First, the increased antenna power is overloading my receiver, and I am receiving AM stations all through the shortwave bands. Second, the antenna I currently have up comes directly into the house, and thus picks up all of the RF noise from the house. I put up a test antenna that comes into the house via a shielded cable, but reception was very bad with a lot of noise (I am guessing I did something wrong).

Anyways, I have been pretty frustrated, so I decided to hop in the car, and head up to the top of the hill (Walter Hass Park which overlooks San Francisco) to see if it was my location, or maybe all shortwave reception is bad. I planned on just checking for 5 minutes, but ended up staying over an hour because the reception was so good.

Here is what I picked up (January 11, 2007 UTC):

Clip of Cuban Jamming of Radio Marti

I have had really good reception tonight, and scanning around I came across a Radio Marti broadcast being jammed by Cuba (I am assuming it is Cuban). First, the details:

Radio Marti :0738 UTC - 0745 UTC, 6030 Khz. SIO 312. Male and Female have a conversation in Spanish. Jamming being broadcast over program (sounds like running water / brook).

Checking Passport to World Band Radio, it confirms Radio Marti at that time and frequency, and that the broadcast is jammed.

Chinese Jamming Reception of Radio Free Asia Broadcasts

As I mentioned the other day, I have been receiving what I believe to be a grayline propagation broadcast of Radio Free Asia (RFA) programing to the Uyghur region of China from Tajikistan every evening around dusk. However, I had not been able to positively ID it, as the programing was just music.

Well, I spent quite a bit of time researching this to try to confirm the original. I download Uyghur music to see if it sounded similar to the music programing I was getting (it did), I searched for and listened to the RFA Uyghur broadcasts to see if they matched (they didn't), and I contacted Radio Free Asia to ask them about their Uyghur programing.