Implement all SSTV Modes

[Reid-n0rc]

Implement all SSTV modes https://en.wikipedia.org/wiki/Slow-scan_television#Modes

Include WeFax as well

Include digital SSTV modes, like EasyPal

[Reid-n0rc]

EasyPal utilizes Digital Radio Mondiale (DRM) encoding to transmit image and data files over narrow 2.5 kHz audio channels. Instead of sending images as raw analog lines, it splits files into separate segments for fast decoding and applies Forward Error Correction (FEC) for noisy paths. This mode, when implemented in SSTVAF should not be called EasyPal

Primary DRM Modes

• Mode A (Fast): Offers the fastest data rate but lacks robust protection against selective fading. Best for short-range VHF/UHF or exceptionally clear HF.
• Mode B (Robust): A slower mode engineered for HF bands, highly resistant to atmospheric noise and signal fading.
• Mode E (Extreme): Tailored for channels prone to large delays and Doppler effects (e.g., long-path propagation or satellite bouncing).

QAM Modulation Schemes

EasyPal modulates data onto RF carriers using Quadrature Amplitude Modulation (QAM), determining throughput speed vs. signal integrity:

• QAM4 (4-QAM / QPSK): Low data rate but highly resistant to noise, ensuring transmissions get through in poor conditions.
• QAM16: Moderate speed and error resilience.
• QAM64: High data rate and data density, ideal for close-range or high-SNR VHF/UHF contacts.

Specialized Transmission Settings

• Hybrid Mode: Instead of sending the entire bulky image directly over the air, this mode sends a compact URL that directs the receiving EasyPal software to automatically grab the image from the internet. DO NOT IMPLEMENT Hybrid Mode!
• Automatic Repeat Request (ARQ/BSR): If noise corrupts packets, receivers can request the transmitter to only resend the missing segments rather than the entire file.

Technical information about DSSTV can be found here: https://www.sstv-handbook.com/download/sstv_10.pdf

[patrickrb]

This issue's original scope ("all SSTV modes + WeFax + EasyPal") is too large for one PR, so it's being split:

• Add 7 analog SSTV modes: Scottie DX, Martin 3/4, PD 160/180/240/290 (#16) #33 — adds a batch of 7 well-sourced analog modes (Scottie DX, Martin 3/4, PD 160/180/240/290). Robot 24 was intentionally skipped (no authoritative segment timing available).
• Implement WeFax (weather fax) mode #34 — WeFax (weather fax), a distinct modulation, tracked separately.
• Implement digital SSTV (EasyPal / HamDRM) #35 — digital SSTV / EasyPal (HamDRM/OFDM), an entirely separate modem, tracked separately.

Additional analog modes can follow the same pattern as #33 as sources allow.