From ff843584ddec86622d5d776ef3cdb7fa0ec6b700 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?L=C3=A1szl=C3=B3=20Bar=C3=A1th?= Date: Thu, 5 Jan 2023 19:24:06 +0100 Subject: [PATCH] Fix "14dB" RF amplification in FAQ (#1252) Also added a comment on why is this value often quoted wrong --- docs/source/faq.rst | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/docs/source/faq.rst b/docs/source/faq.rst index 91fff5eb..010cf89d 100644 --- a/docs/source/faq.rst +++ b/docs/source/faq.rst @@ -116,15 +116,16 @@ HackRF (both Jawbreaker and One) provides three different analog gain controls o The three RX gain controls are at these stages: -- RF ("amp", 0 or 14 dB) +- RF ("amp", 0 or ~11 dB) - IF ("lna", 0 to 40 dB in 8 dB steps) - baseband ("vga", 0 to 62 dB in 2 dB steps) The two TX gain controls are at these stages: -- RF (0 or 14 dB) +- RF (0 or ~11 dB) - IF (0 to 47 dB in 1 dB steps) +Note: in some documents, the RF gain was erroneously quoted to be 14 dB. The confusion was based on the fact that the MGA-81563 amplifier is advertised as a "14 dBm" amplifier, but that specifies its output power, not its amplification. See `Martin Ling's comment on issue #1059 `__ for some details! ---- @@ -132,7 +133,7 @@ The two TX gain controls are at these stages: Why is the RF gain setting restricted to two values? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -HackRF has two RF amplifiers close to the antenna port, one for TX and one for RX. These amplifiers have two settings: on or off. In the off state, the amps are completely bypassed. They nominally provide 14 dB of gain when on, but the actual amount of gain varies by frequency. In general, expect less gain at higher frequencies. For fine control of gain, use the IF and/or baseband gain options. +HackRF has two RF amplifiers close to the antenna port, one for TX and one for RX. These amplifiers have two settings: on or off. In the off state, the amps are completely bypassed. They nominally provide around 11 dB of gain when on, but the actual amount of gain varies by frequency. In general, expect less gain at higher frequencies. For fine control of gain, use the IF and/or baseband gain options. ----