CODECS:
There is a bewildering array of codec choices around. As a HF/MF contester
and DXer (CW, SSB and RTTY), I would like to be able
to listen to a contest or DXpedition recording and have a good chance of
hearing that extremely weak station who was responding to
me while other nearby enormous signals were still calling. This ability to
handle a large dynamic range seems pretty demanding...
Does anyone know of an authoritative site containing comparisons on the
technical performance of various codecs?
ISOLATION TRANSFORMERS:
The WL help files suggest using the small Radio Shack isolation
transformers. They work pretty well for RTTY signals at
2125/2295, but others have pointed out that performance in the lower frequency
range is less than good with lots of distortion
products.
A search of Mouser Electronic's catalog shows conventional audio isolation
transformers are in the $50/each level. That adds up
to serious money quickly.
Confessing now to the fact that I am not an audio engineer, could someone
more experienced in these matters suggest an approach
to choosing audio isolation transformers that introduce a minimum of
impairments to receiver and transmitter audio? My application
is pretty typical for a WriteLog-equipped contest station:
-- computer with 2 soundcards.
-- W5XD Multi+ keyer for SO2R operation.
-- two transceivers, with ~1mW line-level audio input to the transmitter...
and separate line-level audio output, speaker, and
headphone outputs. For my particular transceiver of the moment, the headphone
and speaker audio are from the same source.
Thanks.
-- Eric K3NA
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