Right, here goes. I'm going to do the Ham Radio exam

I decided a couple of weeks ago that I was going to have a bash at the Amateur Radio exam, having been a Short Wave Listener for many years and a one-time 11-metre man with many QSLs from Europe.

The main motivation for this has been provided by my lifelong friend, Brian, who just last Friday received his callsign, EI7GVB, having successfully passed the test in June. Good man Brian. I look forward to working you on the bands!

I was completely daunted at first. Nay, overwhelmed. I looked at the QADV program and tried some questions and was absolutely bamboozled. I am not attending lessons with any radio club, nor engaging in private tuition. No, I'm going to do this myself, with a little help from my friends. Tony EI4DIB might just be one of those helpful friends!

In a matter of days, I have got my act together. I have learned Ohm's law, and the different variations. V = I x R, I = V/R, R = V/I. For resistors in series, add them up and apply the formula. For resistors in parallel, its R1xR2 over R1+R2. Easy peasy? Maybe not, but I think I have a grip on that. Next week it's capacitance and inductance.

Also I have launched into Module 4 of the IRTS Radio Experimenter's Exam Course Guide. Receivers. I'm trying NOT to think about the fact that there are 14 modules to be covered, but rather that I have over ten weeks left before I sit the exam.

Now I might have a wee bit of an aptitude for this stuff, but one cannot help feeling a little overwhelmed when one is starting down the road of learning a lot of stuff for an exam. However, I have applied myself well over the last few days to receivers, and was able this morning to draw a block diagram of a superheterodyne receiver from memory, including the BFO/CIO stage.

In addition, I tried three tests of 30 questions each last night using the QADV program (QADV link) on the subject of Receivers. I scored 90%, 90% and 93%, so something must be seeping through into that chasm in my head.

Some things might be worth mentioning here with are perhaps not explained in detail on the IRTS disk (Link to IRTS disk page). I have taken notes as I went along to help me fill in the knowledge gaps where the disk didn't seem to explain fully. Not that the disk isn't brilliant, just that I want to expand things a bit for anyone else who is studying for the exam.

Automatic Gain Control:

According to QADV, AGC is normally applied at the IF stages.
AGC introduces distortion if applied at the IF stage. Why? Because the bias is too low.
This distortion comes in the form of harmonics.
The S-meter is usually driven from the AGC.
What removes distortion caused by AGC to an IF stage of a receiver? The IF Transformers.
AGC is usually obtained from the detector.