Bandwidth and Filters

Bandwidth and Filters

OpenHPSDR Zeus offers three connected ways to set the RX filter:

1. The BANDWIDTH block — quick mode-appropriate presets and a Custom Hz input.
2. The FILTER block — a 10-slot filter bank plus two user-editable slots (VAR1 / VAR2).
3. The Advanced filter ribbon — a graphical passband editor reached from the ≡ button at the end of the FILTER bank.

All three operate on the same underlying filter; whichever one you touch last wins.

BANDWIDTH block

Five quick presets at the top, plus a CUSTOM <low> – <high> Hz input. The presets are mode-dependent:

Mode group	Presets
SSB / DIG (USB/LSB/DIGU/DIGL)	Narrow 2.7k, Wide 3.0k, 3k, 4k, 6k
CW (CWL/CWU)	CW 250, CW 500 only
AM / SAM / DSB / FM	AM 6.6k, Wide 8.0k, 3k, 4k, 6k

The Custom field accepts an absolute audio-domain range of 0–10 000 Hz, in 50 Hz steps. Press Enter to commit, Escape to cancel. For asymmetric modes (SSB / DIG / CW) you can edit both the low and high cut independently; for symmetric modes (AM / SAM / DSB / FM) the second edge mirrors the first.

FILTER block

A graphical strip showing the current passband — LOW CUT +150 Hz / WIDTH 2.7 kHz / HIGH CUT +2.85 kHz — and a 12-button filter bank:

• Ten fixed F-slots per mode. For SSB this is 5.0k / 4.4k / 3.8k / 3.3k / 2.9k / 2.7k / 2.4k / 2.1k / 1.8k / 1.0k. AM / FM / CW have their own equivalents (e.g. CW slots cluster around 250–500 Hz).
• VAR1 / VAR2 — two persistent user-editable slots saved per mode on the server. Tune the passband to taste, then leave it on VAR1 or VAR2 and OpenHPSDR Zeus will remember it for next time.
• ≡ (hamburger) — opens the Advanced filter ribbon.

Advanced filter ribbon (≡)

A wide ribbon that drops in above the panadapter, giving a much richer passband editor:

• Graphical passband editor — LOW CUT / PASSBAND / HIGH CUT read-outs at the top, draggable handles on a frequency tape underneath. Drag edges to adjust · Drag inside to move.
• PRESET BANDWIDTHS chips on the right — six widths chosen to suit the current mode group. For SSB the widths are 2.4 / 2.7 / 3.6 / 6.0 / 9.0 / 12.0 kHz. CW / AM / FM each have their own preset set.
• CUSTOM ✎ button — clicking the pencil arms VAR1 so the next graphical drag writes into the VAR1 slot. Repeat for VAR2.
• × at the top-right closes the ribbon.

The graphical editor and the BANDWIDTH/FILTER blocks edit the same filter — the ribbon is just a roomier UI surface for the same control.

Practical workflow

• Pick the closest preset in the FILTER bank (e.g. 2.7k for SSB).
• For occasional fine-tuning, drag the edges of the passband on the panadapter.
• For a personally-tuned filter you'll use over and over (say +200 / +2900 Hz for narrowed-up SSB on a noisy day), tune to taste with the Advanced ribbon, then click CUSTOM ✎ to bake it into VAR1 / VAR2. From then on, one click on VAR1 recalls it.