[Elecraft] How reliable an internet connection is needed for A K3 remote to work well?

[iain macdonnell - N6ML]

On Wed, Jul 16, 2014 at 12:13 PM, AG0N-3055 <mcduffie at ag0n.net> wrote:
>
>> Hint: Don't turn knobs like audio or power fast.  Each pulse from the knob
>> is sent as a UDP packet...
>
> I'm late to join this thread, but was curious so read a couple before
> deleting.  What I bring up below may have been discussed before.
>
> I'm not much of a network person, but I believe UDP packets are tossed
> out with no error correction at all (like unproto X25 packet).  Having
> lived in a packet loss environment for a long time (years) and running
> IRLP, I can tell you that when a packet it lost, it is lost.  The
> command, audio, whatever, will be lost and have to be repeated in order
> to get it through.  As I said, this may have been discussed before and
> I'm sorry for any repetition it brings.  It also causes pretty bad holes
> in the audio if it is sent UDP.

The flip-side is that use of a "reliable" protocol, such as TCP, which
detects and retransmits dropped packets, causes increasing latency
over time (the more packets get retransmitted, the further behind
"real time" you get). For something like a "real time" audio stream,
it generally better to just accept the packet-loss. The problem of
increasing latency can affect UDP too - some types of unreliable links
cause a sequence of packets to get queued, then all transmitted in a
burst. This causes a gap in the stream, followed by that increased
latency as all of the packets received in the burst, and any
thereafter, need to get played sequentially. Buffering can help to
smooth this out, but the more you buffer, the greater your baseline
latency, which is a big deal for remote operation - e.g. tuning around
the band, looking for CW signals with a narrow filter engaged - if
there's any significant latency, you've already tuned past the signal
before you hear it. It's a tricky problem area. My personal software
solution uses UDP and a moderately-sized buffer, and when the buffer
builds up to a point where the latency is more than I like, I click a
button to dump the contents of the buffer, and return me to
low-latency.

    ~iain / N6ML