Thanks for this excellent post, Alan! IMO, "mismatch loss" is a figment
of the imagination of those who never get outside the lab. Transmission
lines was one of my favorite EE courses, and I never heard of it until I
heard it referenced in online discussions a few years ago. And the
purported losses in connectors are an urban legend with almost basis in
fact. Several years ago, W8JI poetically observed that if the 1 dB loss
falsely attributed to UHF connectors was true, each would be burning 35
W carrying a legal limit signal, and be starting fires!
Keeping track of losses in systems is, of course, a great thing. Our FD
group runs (and has won several times) FD 1A QRP Battery. Every piece of
coax in our station is low loss RG8 or RG11.
73, Jim K9YC
On 2/11/2018 8:03 PM, Alan wrote:
Hi Al,
Yes, but don't forget that the connector "loss" is a mismatch loss,
not absorptive power loss. In other words, it affects the SWR
slightly but does not actually absorb any power.
If you are using any kind of antenna tuner and tuning for 1:1 SWR,
mismatch "losses" have no effect. Even if you aren't doing that, the
antenna is probably not a perfect 50-ohm resistive load anyway, so the
connectors' mismatches are about as likely to make the SWR better as
worse, depending on the phase and magnitude.
But the general point is sound. Power loss is even more important for
QRP than for QRO even though the number of watts of loss is less.
When the other station can barely hear you, every dB counts!
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