Monday, January 15, 2018

Small Transmitting Loop / Magnetic Loop Design Calculations

The following calculations should be helpful for building a magnetic loop antenna. I make no claims to understanding the math and took it straight from the spreadsheet at Steve Yates AA5TB's spreadsheet.

I've tested this against AA5TB's spreadsheet and the values appear to match. Please let me know if you encounter any bugs!

Input parameters

Parameter Value USC Unit Metric Unit
Design frequency: MHz
Loop diameter: feet m
Conductor diameter: inches mm
Added Loss Resistance: milliohms Caused by poor joins, etc.
RF Power: Watts

Output parameters

Parameter Value USC Unit Alt Unit
Wavelength feet m
Efficiency % dB
Bandwidth kHz (-3 dB)
Loop circumference ft m
Loop area ft2 m2
Radiation resistance
Loss resistance
Total loss resistance
Loop inductance microhenries
Inductive Reactance Ohms
Distributed capacitance picofarads
Quality factor
Tuning capacitor picofarads
Capacitor potential Volts
Minimum plate spacing inches mm

Friday, September 25, 2015

Baofeng UV-B5/UV-B6 Programming Troubles

I learned yesterday that the trusty-and-cheap UV-B5 has been modified and is no longer compatible with CHIRP. Given how much of a pain they are to program from the keypad, that's pretty much a dealbreaker for the UV-B5, even though it's a great radio for the price ($30).  Apparently, you can identify the newer radios by the fact that they have 27 menu options instead of 29.

While researching the problem I was experiencing ("Radio did not ack programming mode"), I found an issue in the bug tracker for CHIRP that recommends using a CP2102-based cable to program the radio as a way of getting around this. It's not ideal, but a CP2102 USB adapter cost me $1.75 on eBay and the radio ships with a headset that we can pull the jack from as an interface. My soldering skills are marginal at best, but this looks about as easy as it gets.

As a bonus, it'll give me a good reason to design and print a case, too!

I will update this post later with my results.

Sou Matome JLPT N2: Grammar Elements and Translations

I've found that having a short English equivalent for grammar elements / sentence patterns as I encounter them in Sou Matome N2 Grammar helps me to retain them. If nothing else, the analysis required to boil them down certainly helps them stick.

Expressions from week one

さびし - a expression of loneliness (on someone's face, etc.)
病気がち - get sick often
忘れっぽい - forgetful-ish
疲れ気味 - feeling somewhat tired
帰れるものなら - if it were that I could return - Requires a potential before it!
暑いものだから - it's because it's hot
知らなかったんだもの - because I didn't know
持っているものの - even though I have
はもとより自転車 - (don't have a) car or even a bicycle - I checked this with Kiyoshi and he confirmed that it emphasizes that, while the reader might expect that the speaker doesn't own a car, the lack of a bicycle would be unexpected.見た目はともかく - Whether or not it looks good, the taste is...
旅行はまだしも - Can handle travel (but not something else)
仕事の話は抜きにして - Omitting work talk
Ex: 田中さん抜きではパーティーは始められません - We can't start the party without Tanaka.
心配でたまらない - So worried that I can't stand it.
何もすることがなくて、暇でしょうがない - Of course I'm bored
うるさくてかなわない - Can't bear the noise
残念でならない - Very disappointed

Expressions from week two

努力のかいがあって - My labor paid off/were worth it as... [The かい from this and かいもなく almost certainly means "value, effect, worth": 効 or 詮]
手術のかいもなく - The surgery wasn't worth it / didn't pay off
やりがい - Worth doing. Also: 教えがいのある生徒 = Students worth teaching.
借金してまで - to go so far as getting a loan
読みかける - haven't finished reading. 読みかけの本 - books I haven't finished reading
読み切る - Read entirely. [This seems to have the meaning of "until it's all used up": 疲れ切った = very tired.]
ありえる・ありうる - Possible to be. [うる apparently can't be negative.]
やりぬく - to do until completed
忘れないうちに - While in a state of not forgetting
終わる終わらないかのうちに - As soon as it ended. ]Lit: While it could have been done or not been done.]


こどもにしたら - こどもには = to a kid
本当だとしたら - 本当ならif that were true
行くとしても - Even if I go
社会参加目的として - With public participation as a goal
家族とともに - 家族と一緒に = With my family
増加に伴って - In connection with the increase. [According to this, can't be used for "with a person". This Stack Exchange post makes it clear that using を instead of に can invert the relationship.]



I'm a few days into the book and working to come up with good English versions of each pattern. More to come!