Re: K3 dumb Q about PPM

[k6xt]

Gents
Lots of confusion about oscillator specs. Allow me to add more.

Specs on TXCO's are given at specific conditions. Deviate from those
conditions and the spec does not apply. In deviating conditions one must
review the manufacturer's spec sheet to discover how the TXCO will respond.

The PPM spec only refers to long term drift, as defined in the
manufacturer's specifications. It has no bearing to short-term changes
in room temperature as suggested in some of the posts. Again, see the
manufacturer's specifications. This is exactly why the (for example) K3
has a TXCO alignment procedure. So that a picky user can adjust the TXCO
exactly on frequency under a specific set of operating conditions.
Deviate from the alignment condition, the TXCO will respond by deviating
from "perfect" alignment. The need to control temperature change and
remove heat is exactly why industrial and military electronics are often
in cold climate controlled spaces where the temperature never varies and
the carbon units wear sweaters.

Lastly, for the newer folks, be happy. We hams used to be in the
business of chasing each other up and down the bands as our oscillators
wandered randomly about. Receiving station wanders one way, transmitting
station wanders the other. Many newer folks may not even know what
"youp" means. These days just about any rig worthy of the name newer
than 20 years old is "rock solid" from turn on +1 minute. And quite a
number, "rock solid" from turn on plus 10 seconds. Try that with the old
Hallicrafters with the valve handwheel knobs where a sharp rap on the
desk sent the rig five kHz up the band!

--
73 Art
Allison, Colorado
"Whether you believe you can do a thing or
not, you are right."  --Henry Ford.

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[lstavenhagen]

>Many newer folks may not even know what
"youp" means. These days just about any rig worthy of the name newer
than 20 years old is "rock solid" from turn on +1 minute. And quite a
number, "rock solid" from turn on plus 10 seconds. Try that with the old
Hallicrafters with the valve handwheel knobs where a sharp rap on the
desk sent the rig five kHz up the band! <

Ok tnx Art and all for the info on this.

I definitely remember the "youp" days, my first rig when I was a novice in the 70's was a Heathkit DX-60B. I was rockbound at the time (tho that was right after the change in the rules allowing novices to use a VFO, I didn't have the money to buy one) and even then, my Heath would give quite a youp/chirp if I didn't set the grid current juuuust so.
My Heath SB's that I had in the 80's/90's didn't chirp or youp, but they drifted like a fishing skiff on the ocean, at least until they got hot. My Drake TR3 was better but it still moved around a bunch. The only thing I like about my 706MKIIG is that it stays put pretty good, but not too useful for much else.

Now my K2 drifts about 20 to 30hz in the first 1/2 hour or so and then it sits very still after that. So the K3 which only ever moves about 4 or 5 hz overall, including changes in temp, is just astonishing to me hi hi.

BTW, my K3 does move with temp just about according to the temp compensation sheet that came with the TCXO.

So IMO we're definitely in the "good old days" of rigs now than before. I'd still love to come across a good DX-60B with good tubes in it, but that's just the collector/nostalgia part. For actually getting on the air my elecrafts are the way to go for me now hi hi.

Tnx for the clarifications es 73,
LS
W5QD
K2 #6882
K3 #4116