user:kurser:ham_vt2023_l11
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| Both sides previous revisionPrevious revision | Next revisionBoth sides next revision | ||
| user:kurser:ham_vt2023_l11 [2023/05/14 09:45] – jonathanl | user:kurser:ham_vt2023_l11 [2023/05/14 09:46] – jonathanl | ||
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| Explain overarching bands: | Explain overarching bands: | ||
| - | * Low frequency (30kHz-300kHz) | + | |
| - | * Medium frequency (300kHz-3MHz) | + | * Medium frequency (300kHz-3MHz) |
| - | * High frequency (3MHz-30MHz) | + | * High frequency (3MHz-30MHz) |
| - | * Very high frequency (30MHz-300MHz) | + | * Very high frequency (30MHz-300MHz) |
| - | * Ultra high frequency (300MHz-3GHz) | + | * Ultra high frequency (300MHz-3GHz) |
| - | * Super high frequency ... | + | * Super high frequency ... |
| - | * Extra high frequency ... | + | * Extra high frequency ... |
| - | * Terrific high frequency ... | + | * Terrific high frequency ... |
| Each band is referred to by it's approximate wavelength. Not exact (example: 40m band has a wavelength 41.6-42.8m). Mention λ[m] = 300/ | Each band is referred to by it's approximate wavelength. Not exact (example: 40m band has a wavelength 41.6-42.8m). Mention λ[m] = 300/ | ||
| You will need to know the start and stop frequency, as well as power of ALL the bands (probably nothing above 70cm comes on the test). Go through all bands (boring!) | You will need to know the start and stop frequency, as well as power of ALL the bands (probably nothing above 70cm comes on the test). Go through all bands (boring!) | ||
| - | * Mention we have mounted antennas which work well on 40m, 20m, 17m, 15m, 6m (yagi), 2m (yagi), 70cm | + | |
| - | * Mention predominant modes used on the band. HF = SSB and AM, VHF is both SSB, AM and FM and UHF = FM. | + | * Mention predominant modes used on the band. HF = SSB and AM, VHF is both SSB, AM and FM and UHF = FM. |
| - | * Most bands are 200W PEP. Non-200W are italic | + | * Most bands are 200W PEP. Non-200W are italic |
| - | * Propagation is best at HF. Probably ask -JKK about this! | + | * Propagation is best at HF. Probably ask -JKK about this! |
| Remember all modes have some bandwidth! Example if you're sending 3kHz USB @ 14.348, you're outside the band by 1kHz! Most radios know this, but some may only check the carrier frequency | Remember all modes have some bandwidth! Example if you're sending 3kHz USB @ 14.348, you're outside the band by 1kHz! Most radios know this, but some may only check the carrier frequency | ||
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| Repeaters need some way to tell noise from signal. Some methods exist | Repeaters need some way to tell noise from signal. Some methods exist | ||
| - | * Carrier wave detection (bärvåg): repeater activates when an FM carrier wave is detected over some threshold. (Not recommended by SSA, prone to being triggered by noise) | + | |
| - | * Tone burst (tonskur, tonöppning): | + | * Tone burst (tonskur, tonöppning): |
| - | * Subtone (CTCSS = continuous tone coded squelch system): Repeater is opened by a low tone (usually below 150Hz) in the FM signal. The tone used depends on the repeater. SSA has recommendation where different regions use different tones. Two nearby repeaters can use different tones to avoid having both repeaters open. Most UHF radios have settings to send this tone when transmitting. | + | * Subtone (CTCSS = continuous tone coded squelch system): Repeater is opened by a low tone (usually below 150Hz) in the FM signal. The tone used depends on the repeater. SSA has recommendation where different regions use different tones. Two nearby repeaters can use different tones to avoid having both repeaters open. Most UHF radios have settings to send this tone when transmitting. |
| - | * DTMF (dual tone multi frequency): Some advanced repeater systems can be controlled and programmed by sending DTMF tones to it. These are the same kinds of tones pressing buttons on a dial phone produces. Not very common as the exclusive method of activation. | + | * DTMF (dual tone multi frequency): Some advanced repeater systems can be controlled and programmed by sending DTMF tones to it. These are the same kinds of tones pressing buttons on a dial phone produces. Not very common as the exclusive method of activation. |
| **Repeater nets** | **Repeater nets** | ||
user/kurser/ham_vt2023_l11.txt · Last modified: 2024/02/13 18:09 by user