I have noticed of late when people fit coils to there portable antennas to reach the lower bands say such as 80m and 160m.
There quiet at first and once those coils warm up there signals get stronger and audio louder. often heard this with GM8OEG/P on 80m and yesterday with GX0OOO/p on 160m
Again is this me or is this actual fact it happens and you need to warm those coils up.
Karl
Or maybe all that RF warms the activator up?
No and no.
Probably a coincidence, Karl, 80 and 160 work better when the sun is low or set so signals will tend to improve near sunset and deteriorate as the morning progresses. Last night when I worked John GX0OOO/P on top band he was barely workable at first but steadily improved as the sun got lower.
Reminds me of a study that I saw once that produced graphs showing the increasing number of mobile phone masts and other graphs showing the decreasing number of sparrows. I bet you cannot guess the (unsupported) conclusion?
Well it’s exactly the same as satellite TV and AIDS. During the early 80 to mid 80s there was massive growth in the number of people contracting AIDS, mainly gay but straight as well. What was appearing all over buildings at the same time? Satellite TV dishes. They are obviously the cause.
Hi Karl,
Any heating of toroidal loading coils in use would be a Bad Thing… either due to the wire heating due to it being inadequate for the current it was carrying, or core heating due to losses in the core beyond it’s ratings… losses from both causes likely to increase with increasing temperature…
As Brian says, the phenomenon you observe is more likely due to the vagaries of propagation.
73 de Paul G4MD
… but the conspiracy theorists say the phone companies had teams of people going round collecting up all the microwaved sparrows…
…and they were delicious!
Karl, in basic propagation theory (and also in practice I have found) top band signals should increase as dusk goes into night as the D layer fades, providing sky wave reflections. Signals should decrease after sunrise as the D layer forms and the signals are absorbed by the D layer in the sky above the operators locations.
73 Phil
They taste remarkably like Swan don’t they?
Well Andy that’s knocked my theory on the head I had put it down to the increase in the potholes in the road
I marinade them in malt whisky and cook them four at a time like a kebab…
Ok thanks for that.
Just seemed strange when heard from time they started to a few minutes later,s after few minutes of broadcasting and good one about the changing of the propagation with falling of dusk or even dawn.
Sparrows, few less, no one will miss them.
100 black birds in a pie. Christ how many sparrows required to fill same pie then 
Karl
Mmm! Blackbirds…
Now you understand my passion for 23cm and a high gain dish - nothing to do with QSO’s 
You don’t have to be mad to post here - but it helps!
He’s only lacking sense of British humor.
Sad not to have been brought up on the Goon Show and their successors!