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# You're telling me a Ham Fisted this Metaphor?

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Okay so in 2020ish, a someone convinced me to get a ham radio license.
...and then I bought Baofeng and just kind of didn't do shit with it for like five years. 
In 2025, I ended up locking in enough to try grinding for a Technician license. I couldn't find any good material online so here's my notes:
# Technician

- nvm I passed this by grinding [hamstudy](https://hamstudy.org)
- If you want a vanity callsign the format is basically:
  - standard 2x3
    - `K\w\d\w\w\w`
  - vanity 1x3
	- `K\d\*\*\*`
- anyway just get a General license instead, I was goaded into testing for it 30 seconds after passing my Technician and went in with 0 prep. I ended up being one question from passing that

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# Amateur Extra

- As of January 2026, I'm still single. Most of the lesbians I know have ham licenses so maybe I can find a GF within RF range.
    - If you didn't die a little on the inside reading that, seek help
    - If you're reading this and don't play Grandblue, hit me up
- I still have not touched my baofeng, I own an RTLSDR and haven't touched that either. I do have three Meshtastic nodes, but I'm at a lower elevation than everyone around me so they're kind of useless
>[!TODO] TODO: Put a picture of them here
- Anyway I think I'm reaching the limit of how much I can memorize Hamstudy. Every other resource I've found online seems like it's trying to have you memorize the test bank as well, so here are my notes for the Amateur Extra exam, much of which is digested from hamstudy and wikipedia and the aforementioned lesbians:

# Rules and Shit (E1)
- **PRB-1** is an FCC document that basically says that localities can't fuck with ham radio equipment (within reason)
	- your HOA can't legally do anything about your massive fucking Antenna but they're damn well gonna try
- The **[National Radio Quiet Zone](https://www.youtube.com/watch?v=eQEGPATQe5s)** is an area in MD, VA, and WV where ~~chicanery~~ RF is banned so that RF research can happen without interference
	- As such, Saul Goodman cannot be contacted here
- **CEPT** seems like some European governing body similar to the FCC?
	- if you're operating a ham station in a CEPT country, you need to have a copy of FCC Notice 16-1048, proof of US Citizenship, and proof of an FCC license ready if authorities ask for it
## Spaaaaaaace (E2A)
- Ham satellites have **store-and-forward**, which lets them hold on to messages until something can receive them
	- Kind of how MQTT works, it'll hold on to a message and get rid of it when it the message gets ACKed
## TV (E2B)
- Cable TV uses the same frequency range as the Amateur 70cm band, so you can fit Fast-Scan TV into the same channels
	- what the fuck does this mean (**E2B08**)
- Transmitting on Channel 2 (VHF TV) is illegal for amateurs
- **Upper Sideband (USB)** modulation with a sound card is only used for SSTV
- **NTSC** runs at 525i, 483 of which are visible, the rest is for vsync and other meta stuff
	- so basically 480i with extra metadata
- **Slow Scan TV** (**SSTV**)
	- doesn't actually do video, just images
	- Sends a header before the image, 
		- contains the **Vertical Interval Signalling** (VIS) to tell you what SSTV mode is being used
			- this is just a 7-bit signal with a parity bit
		- also has the vsync, but that doesn't really matter since SSTV only does one frame at a time
	- the actual image is supposed to contain your callsign
## Contesting (E2C)
- Ham logs are stored in **ADIF** (Amateur Data Interchange Format) files
	- sometimes contests ask for Cabrillo files
	- also wtf is a contest?
## Modes and Procedures (E2D,E)
- **MSK144** is designed for Meteor Scatter
	- Contact can be made on VHF up to 1300mi using Meteor Scatter
- **APRS** (Automatic Packet Reporting System) sends packet data, ie locations/text/weather
- **WSPR** (Weak Signal Propagation Reporter) is for testing propagation
- **Hellschreiber** is for some sort of Fax Machine?
## Propagation (E3)
- **Skip Propagation** (**Skywave**) is when you bounce a signal off of the ionosphere
	- if you hit it at a shallow angle, it'll bounce off at a shallow angle which will get you more distance travelled
- **Trans-equatorial propagation** can be afternoon or evening
	- Afternoon 
		- 4000-5000 miles
		- limited to 60MHz
		- High signal strength, but moderate distortion due to multipath bs
	- Evening
		- Peaks at 7PM-11PM
		- Up to 220MHz, sometimes even 432MHz
		- quenched(tf does that mean?) by moderate to severe geomagnetic disturbances
		- depends on high solar activity
- **Sporadic-E Propagation** 
	- ~~is what happenes to my endocrine system when I'm on a family trip~~
	- is when signals sometimes bounces off the E layer, which gives you less range 
		- usually the bouncing happens higher (in the F layer), which gives you more range
	- Happens around solstices, especially summer
- Turns out you can bounce stuff off the Moon too (**EME**)
	- This is easiest when the moon is closest to the earth (Perigee)
		- (cf Apogee from Shuumatsu Densha Doko he Iku, named such because they're fucking far from Tokyo or wherever they were trying to go)
		- the further the moon is way from the earth, the more signals will spread out by the time it gets there, which will get even worse when it reaches earth again
- **Chordal-Hop** propagation is when you can bounce a signal off the ionosphere back onto the ionosphere without hitting earth, which decreases loss (lets face it, the planet is worse at reflecting RF than an ionized band of gas)
## Measuring Stuff (E4A,B)
- **Frequency Counters** depend on the accuracy of the **Time Base**
	- aka a **Reference Frequency**
- **Standing Wave Ratio**
	- checks for impedance mismatch
	- measures ratio of peak to trough in a standing wave(?)
		- how do you get a standing wave here?
	- can be measured by an **Antenna Analyzer**, **Directional Wattmeter**, or **Vector Network Analyzer**
## Receiving Stuff (E4,C,D,E)
- **Intermodulation** happens when you have two signals with different frequencies passing through a "nonlinear system" (what?), which I guess causes constructive? destructive? interference
	- everything is at least a little nonlinear (again what the *fuck* does that mean)
	- seems like the base frequencies and all their harmonics join in on the interference, I think it's like some sort of clusterfuck of a beat frequency?
	- ![Here's the graph of 270 and 275MHz signals getting intermodulated](Pasted%20image%2020260104133540.png)
	- okay so plugging $f\left(k,x\right)=\sin\left(2.7\cdot kx\right)+\sin\left(2.75\cdot kx\right), f\left(1,x\right)+f\left(2,x\right)+f\left(3,x\right)+f\left(4,x\right)+f\left(5,x\right)+f\left(6,x\right)+f\left(7,x\right)$ into desmos looks nothing like this graph so
- **Automatic Notch Filters** try to figure out what the carrier frequency is and then cancelling them out so you only have the frequencies that actually matter to you
	- the problem is that they sometimes think that CW signals are interference and cut that out as well, which is less than ideal for someone trying to listen receive CW
- **Capture Effect** happens in FM when you have to signals with similar frequency, the receiver will demodulate the stronger one and ignore the weaker one
- **Desensitization** is when you have a transmitter and receiver close to each other which can cause interference
## Circuitry Preamble
- *sigh* I'm sorry Mr. Glass, I may have gotten a 4 on the E&M exam, but I learned jack shit about RLC circuits from your class
- Honestly taking a mobile networks class in grad school didn't help either
### AC
- With Capacitors, current is $90\degree$ ahead of voltage
	- When there's current into an uncharged capacitor, the voltage across it starts to rise, this isn't instantaneous so there's a lag between the current changes and the voltage changes
- With Inductors voltage is $90\degree$ ahead of current
	- Inductors work the opposite of capacitors(?), so the voltage changing comes first and the current changes after a lag
## Circuit City (E5,6,7)
- Microwave freqs need short connections to reduce phase shift
	- what?
- Emitter Follower/Common Collector Amplifier
	- has the RX and TX signals in phase
	- Has a gain close to 1 (doesn't amplify voltage, but boosts current?)
	- ....I'm not actually sure how this works and I'm too sleep to look it up

- **Parasitic Inductance** is a thing that fucks with Capacitors
	- physically bigger capacitors have more of this, tends to cause issues for RF
- Two types of **Semiconductors**
	- **N-Type** is negative since it has extra electrons
	- **P-Type** is positive since it doesn't have enough electrons
- A **Decade counter** sends one pulse out for every 10 it receives
- A **step-start** circuit gradually increases the voltage going into filter capacitors when you turn it on
	- if you put all of it in at once, you'll fry it
### Filters
- A **Cavity filter** has a high Q (what is Q?), can handle high power and can survive temp changes, it also has a steep falloff so you don't lose or gain more frequencies than you expect
	- good for a 2m repeater duplexer because of high Q (I don't know what this means)
- **LC filters** use a capacitor and an inductor (I assume from the name)
, and don't do well when those components aren't ideal
- **Crystal filters** don't do well with high power
- **DSP filters** digitally filter stuff 
	- often not ideal since an you'd need to lower the power into the ADC to not fry it, and then boost the power coming out of the DAC
	- They do work well when the input is already low power
- The ~~**Furry Transfem**~~ Fourier Transform converts signals between time and frequency domain
- it basically takes an input wave and breaks it down into the component frequencies
- with music for example, you can take a piece of audio and figure out what notes are being played
	- > [!TODO] TODO: get a picture of Fruity Wave Candy here
### Amplifiers
- **Op-amp**
	- Voltage amplifier
		- in theory, infinite input impedance, 0 output impedance
- Amplifier Classes:
	- Class A: used for AM and SSB
	- Class B: used for RF power amps and push-pull circuits(?)
	- Class AB: used for SSB
	- Class C: CW and FM
		- Conducts <50% of the input and distorts output, so maybe don't use it for something like a SSB phone signal
		- CW doesn't give two shits about distortion as long as you've got a high and low state and consistent timing so it's not affected
		- I couldn't tell you why/how FM is a good usecase for this
### Oscillators
- **Colpitts**: Uses a capacitor divider to create feedback, resonance circuit has inductors and capacitors
	- huh
- **Hartley**: Uses an inductor with a tapped coil for feedback, can generate a range of frequencies
- **Pierce**: like Colpitts, but uses a crystal to stabilize frequency and generate more accurate signals
## Digital Signals (E8)
- **Audio Freq Shift Keying (AFSK)** sends beep boops into a transmitter which sends them as AM/FM/SSB/what have you
	- if the beep boops are too loud going into the transmitter, shit goes wrong with the Carrier Frequency (**Overmodulation**, and apparently also **Intermodulation Distortion**)
	- This does AoE damage to the band and pisses off everyone whose signal you just interfered with
- **ADC**s are **Analog Digital Converters**, which also happen to be the opposite of DACs
	- The **Nyquist-Shannon Theorem** states that to reproduce a signal, you need to sample it at double the bandwidth (highest-lowest frequency)
		- CD Audio is sampled at 44.1kHz, which is a little bit more than the human audible hearing range (20Hz-20KHz)
	- An 8-Bit ADC can quantize signal down to 8 bits
		- This is one of the questions on the exam so it's a freebie
		- Uses **dithering** to smooth out quantization artifacts
		- TODO: put a picture of dithered vs undithered text/indexed color

## Antennas (E9)
- $\frac14\lambda$ vertical antenna
	- Two $\frac14\lambda$ vertical antennas can be used for directionality
		- $\frac12\lambda$ apart in phase yields a figure-8 radiation pattern broadsidei to the axis
		- if they're out of phase, it's the same pattern along the axis
		- $\frac14\lambda$ apart in phase $90\degree$ out of phase is a cardioid 
	- If it's mounted on the ground, you can might lose some of the RF energy into the soil (?????), you can mitigate this by using a **Ground Radial system**, which lets you send the extra current into not soil(???) which somehow helps
- 160m and 80m Antennas need directivity due to atmospheric noise
	- At low HF frequencies, ligthning and other stuff generates RF interference that travels far (due to ionosphere refraction)
	- tl;dr Antenna gain isn't gonna do shit to fix the SNR wrt atmospheric noise
- An **Isotropic Antenna** is the spherical cow of the radio world
- **Yagi Antennas**
	- ![](Pasted%20image%2020260104130032.png)
	- can use a Beta/Hairpin matching system to change the impedance 
		- involves using a loop (sometimes shaped like a hairpin) across the terminals of the antenna, which makes the coil act as an inductor
	- This improves antenna performance by reducing reflections of RF energy back down the TX line
- **Pennant Antenna** is a single-turn terminated loop?
	- tf does this look like
	- Creates a cardioid radiation pattern
- **Folded Dipole Antenna**
	- $\frac12\lambda$ with a wire in parallel connecting both ends
		- how is this different than a pennant
		- it's literally just a $1\lambda$ wire folded in half
		- I can't find a copyright free pic but just imagine the schematic looks goofy
- **Gamma Matching** is when a you (impedance?) match a coax cable to an antenna by connecting the shielding to the center of the antenna and putting the coax conductor some fraction of the wavelength away
	- if your impedance is less than 50ohms,this should do the trick?
	- I'm gonna be honest I barely understand what impedance is, forget impedance matching
	- anyway Yagi Antennas rarely have 50ohm impedance so like gamma matching is good for those
- **Sense Antenna** is a second dipole(?)/vertical antenna that can be combined with a loop/loopstick antenna(?) this gets you a cardioid pattern which is good for direction finding
	- cardioids have a single point at the origin (the test calls them **nulls**) which lets you get a general sense of where a signal is coming from
	- You'd then switch to a more directional antenna (with more nulls) to get a more precise lock on where it's coming from
- $\frac14\lambda$ **impedance transformer**/**Q-section**
	- idk what this actually is
	- $Z_o=\sqrt{Z_iZ_L}$, where $Z_o$ is the impedance of the transformer, $Z_i$ is the input impedance, and $Z_L$ is the TX line impedance
		- so if you have a 100ohm feed and a 50ohm line, you'd have a $\sqrt{100\cdot50}\approx70$ohm transformer
		- if you're matching within $\pm10\%$ of $Z_o$ things will work out
- **Wilkinson Divider** is a passive component used in microwave circuits to either split power into two equal outputs or to combine two inputs into one. The outputs are electrically isolated which reduces crosstalk
### Antenna Gain/Loss
- the formula for gain is $G=10log(\frac{P_{output}}{P_{input}})$
	- alternatively $P_o=P_i\cdot10^{G/10}$, or $P_i=P_o\cdot10^{-G/10}$
- Losses and Gains add up linearly
	- for example $4dB \text{ feed line Loss} + 3.2dB \text{ duplexer loss} + 0.8dB \text{ circulator loss} = 8db\text{ total loss}$
	- add on $10dB$ gain and you've got $2dB$ of total gain