
+-+-+-+-+-+-+
|B|R|U|I|S|E|
+-+-+-+-+-+-+

home | categories | readme

Foundation Radio Exam Notes

In the UK radio hobbyists are required to pass an exam in order to experiment with radio transmissions. The entry level exam is the Foundation. The notes on this page will refer to that. (I have an exam booked, so will hopefully pass soon!)

Online resources:

The Foundation level requires only basic knowledge of how the radio functions and the rules around its usage. A lot of it is simple electronics/physics knowledge that you might have learned at school. In the mock exam papers a lot of the difficulty seems to come from tricky wording. Rereading the questions, using the time available, the information sheets and a calculator is advised.

Acronyms/Annoying abbreviations/Formulas

PIVVIR ~ (POWER) P = I * V , V = I * R

Feeder connector types: Station- N Type (normal), PL259 (plastic); Handheld- BNC (bastard), SMA (small)

DAC Digital to Analog converter.

Balun Balanced to unbalanced adapter. Used between antenna and feeder. Takes unablanced coax and converts to two signals.

Wavelength = 300 / Frequency (MHz) This can be divided by 4 to get dipole antenna length.

ERP, EIRP Effective Radiated Power calculates the effect of focussing gain caused by the power fed to the antenna. There's a table below. EIRP uses an isotropic reference. It's a theoretical antenna that radiates equally in all directions. 10W EIRP = 6.1W ERP. EIRP(db) = ERP(db) + 2.15, EIRP(W) = 1.64 * ERP(W).

(This table included in reference sheet)

Gain in dB	Multiplier
3	2x
6	4x
9	8x
10	10x
12	16x

IGNIRP International Commission of Non-Ionising Radiation Protection.

The antenna should act like a 50Ω resistor. If not signal is reflected back to the feeder. This reflection can sause standing waves (at points where the transmitted and reflected signals combine.) This gives the SWR Standing Wave Ratio, which is measured by an AMU Antenna Matching Unit. This should read 1.5:1 or better. More than this risks damage to the transmitter.

Weather might affect propogation at UHF and higher. Rain/snow might decrease range. Ducting (warm air layer) might increase range.

IONOSPHERE is 70-400km above the earth. It has different layers. D Layer (60km), E Layer (120km) SPoRaDiC E wHErE thE DUctINg HapPeNs, F1 & F2 Layers(>180km).

Callsigns! Foundation begin M3, M6, M7. Intermediate, 2. Full G0-8, M0, M1.

A RSL Regional Secondary Locator is added after the first letter, ie. M#3 :

D - isle of manDy
I - northern Ireland
J - Jersey
M - Mountains? scotland
U - gUernsey
W - Wales

E is added for England at Intermediate.

Suffixes are used for specifying additional bits: /A Alternative Address; /P TemPorary Location; /M Mobile. (Not for Foundation, Intermediate: /MM Maritime Mobile). Airborne use is not permitted at all.

Block diagrams of transmitters and receivers:

Transmitter:


    mic -> MIC AMP -> MODULATOR+[CARRIER OSCILLATOR] -> RF POWER AMP -> Antenna

Receiver:


    antenna->[rf amplifier ]->Demodulator->[audio amplifier]->speaker

Mains plug: Blue - Neutral (Blue Hotel), Brown - Live, Green/Yellow - Earth. Fuse appropriate to device.

Frequency range	Band
30kHz - 300kHz	LF
300kHz - 3MHz	MF [ 1MHz = 300m ]
3MHz - 30MHz	HF [ 3MHz = 100m, 10MHz = 30m ]
30MHz - 300MHz	VHF [ 30MHz = 10m, 100MHz = 3m ]
300MHz - 3000MHz	UHF [ 300MHz = 1m, 1000MHz = 30cm ]
3GHz - 30GHz	SHF

categories: radio

~gg 08/23


+-+-+-+-+-+-+
|B|R|U|I|S|E|
+-+-+-+-+-+-+