Variometers are variable inductance coils.
There are two solenoids, one rotating inside the other.
Maximum inductance occurs when the two coils are in phase.
Minimum inductance when in antiphase.
Advantage - no switches.

DO NOT USE IN TRANSMITTER HIGH POWER CIRCUITS !

The whole length of wire is in circuit at all settings of the variometer.

Consequently as the inductance decreases the wire resistance remains
constant.

So coil Q falls to very low values at small inductance values. i.e., at the
high frequency end of the tuning range - where higher losses and an
increase in temperature are already at their worst.

If the two coils are of similar sizes then Q can fall to near zero at low
inductance settings.

Some variometers have the inside coil much smaller than the other. The
inductance range is relatively small. The reduction in Q may be acceptable
for low power applications and receiving purposes.

But the motion of the two coils, one inside the other, built into a working
transmitter would fascinate visitors to the shack. An attraction quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30 MHz.
It's even better than watching one set of 500pF capacitor plates slowly
disappearing inside the other.
----
Reg.

Reg Edwards wrote:
. . .
But the motion of the two coils, one inside the other, built into a working
transmitter would fascinate visitors to the shack. An attraction quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30 MHz.
It's even better than watching one set of 500pF capacitor plates slowly
disappearing inside the other.
----

Here in the U.S., where conspicuous excess is widely considered a virtue
(big guns, big trucks, big bellies, big antennas, big power. . .), you'd
surely have to include a fluorescent tube suspended in the middle. It's
especially important now that 866A's have become passe.

(I have fond memories from my childhood of a neighbor ham, ...BFB --
'Barrel Full of Beer', who ran a kW -- at least -- of AM into a lazy H
antenna which had a 4 foot fluorescent tube at each of the 4 wire ends.
It impressed me as being really cool -- but then I was 11 at the time.)

Roy Lewallen, W7EL

Roy Lewallen wrote in message ...
Reg Edwards wrote:
. . .
But the motion of the two coils, one inside the other, built into a working
transmitter would fascinate visitors to the shack. An attraction quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30 MHz.
It's even better than watching one set of 500pF capacitor plates slowly
disappearing inside the other.
----

Here in the U.S., where conspicuous excess is widely considered a virtue
(big guns, big trucks, big bellies, big antennas, big power. . .), you'd
surely have to include a fluorescent tube suspended in the middle. It's
especially important now that 866A's have become passe.

(I have fond memories from my childhood of a neighbor ham, ...BFB --
'Barrel Full of Beer', who ran a kW -- at least -- of AM into a lazy H
antenna which had a 4 foot fluorescent tube at each of the 4 wire ends.
It impressed me as being really cool -- but then I was 11 at the time.)

If it wasn't for the fluorescent tube I taped to the wire going out
the back window of my bedroom to a neighbor's tree yonder I never
would have found the hot spot tap on my 80M ARC-5 tank coil. 1953 age
16? Precocious I was not and I still ain't. I forget. But then I
discovered that tuning up by maxing the output of Mrs. Chandler's, the
next door neighbor the pore thing, bathroom lamp was a more better
route to go than the fluorescent tube when it got down to flooding the
neighborhood with RF then tuning around with the S-40B for a contact.

We're ALL nuts.


Roy Lewallen, W7EL

w3rv

"Brian Kelly" wrote in message
om...
Roy Lewallen wrote in message
...
Reg Edwards wrote:
. . .
But the motion of the two coils, one inside the other, built into a
working
transmitter would fascinate visitors to the shack. An attraction quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30
MHz.
It's even better than watching one set of 500pF capacitor plates slowly
disappearing inside the other.
----

Here in the U.S., where conspicuous excess is widely considered a virtue
(big guns, big trucks, big bellies, big antennas, big power. . .), you'd
surely have to include a fluorescent tube suspended in the middle. It's
especially important now that 866A's have become passe.

(I have fond memories from my childhood of a neighbor ham, ...BFB --
'Barrel Full of Beer', who ran a kW -- at least -- of AM into a lazy H
antenna which had a 4 foot fluorescent tube at each of the 4 wire ends.
It impressed me as being really cool -- but then I was 11 at the time.)

If it wasn't for the fluorescent tube I taped to the wire going out
the back window of my bedroom to a neighbor's tree yonder I never
would have found the hot spot tap on my 80M ARC-5 tank coil. 1953 age
16? Precocious I was not and I still ain't. I forget. But then I
discovered that tuning up by maxing the output of Mrs. Chandler's, the
next door neighbor the pore thing, bathroom lamp was a more better
route to go than the fluorescent tube when it got down to flooding the
neighborhood with RF then tuning around with the S-40B for a contact.

We're ALL nuts.


Roy Lewallen, W7EL

w3rv

Put a fluorescent lamp on your mobile antenna.
What fun!
And yes, we must all be nuts.
;^)
73, H.

"H. Adam Stevens, NQ5H" wrote:

"Brian Kelly" wrote in message
om...
Roy Lewallen wrote in message
...
Reg Edwards wrote:
. . .
But the motion of the two coils, one inside the other, built into a
working
transmitter would fascinate visitors to the shack. An attraction quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30
MHz.
It's even better than watching one set of 500pF capacitor plates slowly
disappearing inside the other.
----

Here in the U.S., where conspicuous excess is widely considered a virtue
(big guns, big trucks, big bellies, big antennas, big power. . .), you'd
surely have to include a fluorescent tube suspended in the middle. It's
especially important now that 866A's have become passe.

(I have fond memories from my childhood of a neighbor ham, ...BFB --
'Barrel Full of Beer', who ran a kW -- at least -- of AM into a lazy H
antenna which had a 4 foot fluorescent tube at each of the 4 wire ends.
It impressed me as being really cool -- but then I was 11 at the time.)

If it wasn't for the fluorescent tube I taped to the wire going out
the back window of my bedroom to a neighbor's tree yonder I never
would have found the hot spot tap on my 80M ARC-5 tank coil. 1953 age
16? Precocious I was not and I still ain't. I forget. But then I
discovered that tuning up by maxing the output of Mrs. Chandler's, the
next door neighbor the pore thing, bathroom lamp was a more better
route to go than the fluorescent tube when it got down to flooding the
neighborhood with RF then tuning around with the S-40B for a contact.

We're ALL nuts.


Roy Lewallen, W7EL

w3rv

Put a fluorescent lamp on your mobile antenna.
What fun!
And yes, we must all be nuts.
;^)
73, H.

It's from too much exposure to RF!

Irv VE6BP
--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada

"Irv Finkleman" wrote in message
...
"H. Adam Stevens, NQ5H" wrote:

"Brian Kelly" wrote in message
om...
Roy Lewallen wrote in message
...
Reg Edwards wrote:
. . .
But the motion of the two coils, one inside the other, built into a
working
transmitter would fascinate visitors to the shack. An attraction
quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30
MHz.
It's even better than watching one set of 500pF capacitor plates
slowly
disappearing inside the other.
----

Here in the U.S., where conspicuous excess is widely considered a
virtue
(big guns, big trucks, big bellies, big antennas, big power. . .),
you'd
surely have to include a fluorescent tube suspended in the middle.
It's
especially important now that 866A's have become passe.

(I have fond memories from my childhood of a neighbor ham, ...BFB --
'Barrel Full of Beer', who ran a kW -- at least -- of AM into a lazy H
antenna which had a 4 foot fluorescent tube at each of the 4 wire
ends.
It impressed me as being really cool -- but then I was 11 at the
time.)

If it wasn't for the fluorescent tube I taped to the wire going out
the back window of my bedroom to a neighbor's tree yonder I never
would have found the hot spot tap on my 80M ARC-5 tank coil. 1953 age
16? Precocious I was not and I still ain't. I forget. But then I
discovered that tuning up by maxing the output of Mrs. Chandler's, the
next door neighbor the pore thing, bathroom lamp was a more better
route to go than the fluorescent tube when it got down to flooding the
neighborhood with RF then tuning around with the S-40B for a contact.

We're ALL nuts.


Roy Lewallen, W7EL

w3rv

Put a fluorescent lamp on your mobile antenna.
What fun!
And yes, we must all be nuts.
;^)
73, H.

It's from too much exposure to RF!

Irv VE6BP
--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada
Irv
That's like saying you can get too much sex.
73, H.

H. Adam Stevens, NQ5H wrote:

"Brian Kelly" wrote in message
om...

Roy Lewallen wrote in message
...

Reg Edwards wrote:

. . .
But the motion of the two coils, one inside the other, built into a
working
transmitter would fascinate visitors to the shack. An attraction quite
capabable of overcoming the disadvantage of a ridiculous low Q at 30
MHz.
It's even better than watching one set of 500pF capacitor plates slowly
disappearing inside the other.
----

Here in the U.S., where conspicuous excess is widely considered a virtue
(big guns, big trucks, big bellies, big antennas, big power. . .), you'd
surely have to include a fluorescent tube suspended in the middle. It's
especially important now that 866A's have become passe.

(I have fond memories from my childhood of a neighbor ham, ...BFB --
'Barrel Full of Beer', who ran a kW -- at least -- of AM into a lazy H
antenna which had a 4 foot fluorescent tube at each of the 4 wire ends.
It impressed me as being really cool -- but then I was 11 at the time.)

If it wasn't for the fluorescent tube I taped to the wire going out
the back window of my bedroom to a neighbor's tree yonder I never
would have found the hot spot tap on my 80M ARC-5 tank coil. 1953 age
16? Precocious I was not and I still ain't. I forget. But then I
discovered that tuning up by maxing the output of Mrs. Chandler's, the
next door neighbor the pore thing, bathroom lamp was a more better
route to go than the fluorescent tube when it got down to flooding the
neighborhood with RF then tuning around with the S-40B for a contact.

We're ALL nuts.


Roy Lewallen, W7EL

w3rv


Put a fluorescent lamp on your mobile antenna.
What fun!
And yes, we must all be nuts.
;^)
73, H.


Or a neon lamp. Don't forget that the energy needed to illuminate your
lamp is taken from the energy budgeted to transmission of
intelligence(?).

Dave Nagel WD8BDZ

"...energy budgeted to transmission of
intelligence(?)"

.... ... We're kinda 'pushing' it there, aren't we??
'Doc

'Doc wrote:

"...energy budgeted to transmission of
intelligence(?)"

... ... We're kinda 'pushing' it there, aren't we??
'Doc
Well yes if you must know.....

Dave