Another is that some rigs have transmit filters that are only usable
in FSK mode
Actually, that is receive filters. Nearly all of the older Kenwood,
Icom and Yaesu rigs limited the narrow filter to "RTTY" (FSK) mode
only. Icom still limits its "twin peak" filter to RTTY only.
While many rigs are not as clean on FSK as they can be on AFSK, FSK is
a whole lot cleaner than many AFSK signals (particularly those with
"Windows noises", hum, clipping products from over driving the mic
preamp, RFI due to uncorrected common mode RF on the antenna leads,
open ground connections, audio from open microphones, etc. With FSK it
is easier to generate a "passable" signal for those who either do not
care or don't know how to generate a clean AFSK signal.
73,
... Joe, W4TV
On 10/26/2017 6:21 PM, iain macdonnell - N6ML wrote:
On Thu, Oct 26, 2017 at 12:56 PM, Peter Laws <plaws0@gmail.com> wrote:
On Thu, Oct 26, 2017 at 2:14 PM, David G3YYD <g3yyd@btinternet.com> wrote:
from FTDI. But why spend money on a box when you can just use AFSK for a
very small sum in making your own sound card to rig lead.
Why do some hams use a straight key for CW? A there are any number of
keyers and interfaces that can produce perfectly timed CW using a
keyboard for input.
That's kindof a weak argument. Sending CW with a straight-key is a
skill (some would say an art). There's no special (operating) skill
involved in FSK vs. AFSK.
The usual argument for FSK is that you don't have to worry about
getting the audio level right, and keeping the audio clean. Another is
that some rigs have transmit filters that are only usable in FSK mode
(IIUC).
73,
~iain / N6ML
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