On Mar 4, 12:48?pm, Mike Coslo wrote:
Solid state transmitters are notoriously finicky about matching to the
antenna. Tube equipment is not, so I am told, and early experience seems
to bear that out.

IMHO, it's really a matter of the actual circumstances. As far
back as the late 1950s there were hollow-state ham rigs made
that were meant for 50 ohm loads only. In fact, there
were some HF tube ham rigs made that required no conventional tuneup
at all (CE 100V, 200V, 600L).

Certainly I can see one of my newer rigs start to fold back at 2:1.

Most hollow-state ham rigs can handle 2:1 SWR no problem.
Sometimes there is less tolerance for loads that are highly
reactive, though.

What are the practical limitations of the Tube finals apparent
flexibility?

It's really a matter of how the rig was designed.

Many 1950s hollow-state ham rigs were built with pi-networks that
could match a wide variety of loads efficiently. The EF Johnson Viking
2 is a classic example of that type. Many
homebrew designs also had such pi-networks.

The problem is that the components for such a wide-range network tend
to be large, heavy and expensive. So in the late 1950s and early
1960s, rigmakers designed more for compactness than for wide matching
range. Still, the typical
ham rig of those days could usually handle SWR of 2:1 or
less with no problems.

Is it safe to compare the load, plate, and drive controls to some of the
functions of a tuner? (possible real dumb question)

Not a dumb question at all IMHO.

The short answer is "no". Tuning up a hollowstate
ham rig is a similar but not identical to adjusting the
typical tuner.

Some may tell you that all it takes to tune up a tube
transmitter is to "peak the grid and dip the plate", but
that's simply not correct. Tuneup procedures vary
according to rig design and you have to be specific.

Of course once you get the hang of it, the procedure
rapidly becomes second nature.

What specific hollowstate rigs are you considering?

73 de Jim, N2EY

On Mar 4, 12:53?pm, wrote:
On Mar 4, 12:48?pm, Mike Coslo wrote:

Some may tell you that all it takes to tune up a tube
transmitter is to "peak the grid and dip the plate", but
that's simply not correct. Tuneup procedures vary
according to rig design and you have to be specific.

Sorry, but that was procedure for pre-WW2 high-
power HF transmitters. While it is a simplistic
phrase, it still applies. A more exact procedure
was to tune up the exciter with reduced drive
power and literally peak the grid current. Plate
current was then observed with the plate tuning
adjusted for a slight, but observable dip in plate
current. Of (perhaps) greater importance was setting
the neutralizing control for minimum grid current;
"dipping" the plate current should produce the least
grid current peak on adjusting the plate tuning.

For best results on setting the load-side capacitor
of the common pi-network without a bidirectional
power meter, a detector way out in the field with
meter next to the transmitter is the simplest way
to "tune" that capacitor. However, with about 34+
other high-power transmitters all in the antenna
field, that is impractical; presets for that control
would suffice. The load capacitor of a pi-net has
the least effect on tuning to a new frequency.

When someone does about two QSYs per shift
on at least 15 different transmitters with pi-network
output circuits (all with vacuum tube PAs), yes,
one "gets used to it" but what I described was the
correct phrase.

The pi-network has been around and used in HF
transmitters since at least the late 1930s and has
survived past the start of the semiconductor era.
However, the convenience of broadband transistor
power amplifiers has pretty much tossed that whole
tube tuning procedure. Used with a Bruene detector
sensor for an automatic antenna tuner, it makes
QSYing a snap, even jumping bands (with a broad-
band antenna, of course).

"Peak the grid and dip the plate" is an old correct
phrase. It will be found mentioned in the current
US amateur radio question pools.

Yes, there are exceptions. I was once involved with
a distributed amplifier design that would cover over
an octave of spectrum using tubes and was NOT
tuned at all in normal operation. Since that one
involved over a dozen vacuum tubes (ceramic-metal
medium-power types), it would not be suitable for
ordinary amateur radio HF transmitter stations. The
vertical amplifier of the old Tektronix 54n series
oscilloscopes used push-pull tube-type (all glass
envelope "receiving" type) distributed vertical deflection
amplifier.

The pi-network output circuit was a favorite among
amateur homebrewers for decades due to its
simplicity and better ability to attenuate harmonics,
that coming to be more and more prominent in
regulations as HF users became more plentiful.

On Mar 4, 11:21 pm, "
wrote:
On Mar 4, 12:53?pm, wrote:

On Mar 4, 12:48?pm, Mike Coslo wrote:
Some may tell you that all it takes to tune up a tube
transmitter is to "peak the grid and dip the plate", but
that's simply not correct. Tuneup procedures vary
according to rig design and you have to be specific.

Sorry, but that was procedure for pre-WW2 high-
power HF transmitters.

Sure it was.

While it is a simplistic
phrase, it still applies. A more exact procedure
was to tune up the exciter with reduced drive
power and literally peak the grid current. Plate
current was then observed with the plate tuning
adjusted for a slight, but observable dip in plate
current. Of (perhaps) greater importance was setting
the neutralizing control for minimum grid current;
"dipping" the plate current should produce the least
grid current peak on adjusting the plate tuning.

A number of amateur transmitters/transceivers have used a quick
peaking of the drive/preselector control followed by adjustment of
tune and load controls for maximum output, keeping readings within
operating parameters. I've never seen an amateur transmitter with a
front panel neutralizing capacitor. Neutralization is normally a set
and forget procedure which one needn't worry about until the final
tubes are replaced.

Tuning for maximum output for a given amount of drive has become the
norm in tuning high power, vacuum tube linear amplifiers. All one
needs do is make certain that the bottles don't aren't drawing too
much grid current. A check of linearity can be made with the station
monitor 'scope.

The load capacitor of a pi-net has
the least effect on tuning to a new frequency.

That would depend upon the antenna being used and the amount of
frequency change as well as the type of equipment being used. Some
manufacturers switch in some fixed capacitance on various bands or
portions of bands.

The pi-network output circuit was a favorite among
amateur homebrewers for decades due to its
simplicity and better ability to attenuate harmonics...

....but the Pi-L did a much better job of attenuating harmonics with
only a little more circuit complexity. Quite a number of Novice
licensees found themselves in receipt of OO notices or letters from
the FCC when using a simple pi-net output tank with a multiband
antenna.

Dave K8MN

wrote in
oups.com:


Most hollow-state ham rigs can handle 2:1 SWR no problem.
Sometimes there is less tolerance for loads that are highly
reactive, though.

What are the practical limitations of the Tube finals apparent
flexibility?

It's really a matter of how the rig was designed.

Many 1950s hollow-state ham rigs were built with pi-networks that
could match a wide variety of loads efficiently. The EF Johnson Viking
2 is a classic example of that type. Many
homebrew designs also had such pi-networks.

The problem is that the components for such a wide-range network tend
to be large, heavy and expensive. So in the late 1950s and early
1960s, rigmakers designed more for compactness than for wide matching
range. Still, the typical
ham rig of those days could usually handle SWR of 2:1 or
less with no problems.




Is it safe to compare the load, plate, and drive controls to some of
the functions of a tuner? (possible real dumb question)

The short answer is "no". Tuning up a hollowstate
ham rig is a similar but not identical to adjusting the
typical tuner.

Some may tell you that all it takes to tune up a tube
transmitter is to "peak the grid and dip the plate", but
that's simply not correct. Tuneup procedures vary
according to rig design and you have to be specific.

Of course once you get the hang of it, the procedure
rapidly becomes second nature.

I enjoy twiddling knobs, kind of the same way I like a manual
transmission. 8^)


What specific hollowstate rigs are you considering?


Last year at Dayton I purchased a 40 and 80 meter Heathkit single
Bander as a learning tool - they are pretty simple. I restored the
80 meter unit, and will start on the 40 meter one sometime. I am now
looking at a Kenwood TS-830S. It's a hybrid, with tube finals. I
really like it so far, although I don't see it replacing my IC-761.
I am hooked on computer control of the newer rig - sometimes! Other
times I just like that retro aspect.

- 73 de Mike KB3EIA -

On Mar 4, 6:57�pm, Mike Coslo wrote:
wrote groups.com:

Most hollow-state ham rigs can handle 2:1 SWR no problem.
Sometimes there is less tolerance for loads that are highly
reactive, though.

What are the practical limitations of the Tube finals apparent
flexibility?

It's really a matter of how the rig was designed.

Many 1950s hollow-state ham rigs were built with pi-networks that
could match a wide variety of loads efficiently. The EF Johnson Viking
2 is a classic example of that type. Many
homebrew designs also had such pi-networks.

The problem is that the components for such a wide-range network tend
to be large, heavy and expensive. So in the late 1950s and early
1960s, rigmakers designed more for compactness than for wide matching
range. Still, the typical
ham rig of those days could usually handle SWR of 2:1 or
less with no problems.
Is it safe to compare the load, plate, and drive controls to some of
the functions of a tuner? (possible real dumb question)
The short answer is "no". Tuning up a hollowstate
ham rig is a similar but not identical to adjusting the
typical tuner.

Some may tell you that all it takes to tune up a tube
transmitter is to "peak the grid and dip the plate", but
that's simply not correct. Tuneup procedures vary
according to rig design and you have to be specific.
Of course once you get the hang of it, the procedure
rapidly becomes second nature.

I enjoy twiddling knobs, kind of the same way I like a manual
transmission. 8^)

It's a question of skill vs. automation.

What specific hollowstate rigs are you considering?

* * Last year at Dayton I purchased a 40 and 80 meter Heathkit single
* * Bander as a learning tool - they are pretty simple. I restored the
* * 80 meter unit, and will start on the 40 meter one sometime.

I think you mean the Heath HW-12 and HW-22, or the later
A models of the same rigs.

They are from the early-to-mid 1960s, and have very limited
matching range. They are really only meant to match a 50
ohm load. Note that there isn't even a LOADING control on
them.

The Single Banders were Heath's answer to the "SSB is too
expensive" idea. Every possible simplification and economy
measure was used in them, yet the result is a usable 100 W
class SSB transceiver for one HF ham band. Note that the
75 meter one stops at 3.8 MHz. Heath figured that by
simplifying the output pi network to the most extreme degree,
they could save a few dollars. Coming up with a 50 ohm
antenna was the ham's problem.

I am now
* * looking at a Kenwood TS-830S. It's a hybrid, with tube finals. I
* * really like it so far, although I don't see it replacing my IC-761.

That's a pretty good rig for its era. The matching range is limited
but it will handle 2:1 SWR without problems IMLE.

I am hooked on computer control of the newer rig - sometimes! Other
* * times I just like that retro aspect.

One of the great things about amateur radio today is that we can
use a wide variety of technologies for the same or similar purposes.

I find it ironic that the evolution of the "state of the art" has come
full circle in about a half-century, at least in HF/MF:

- Ham rigs of the 1950s usually had wide range pi-nets which required
adjustment, but would match almost anything without an external
device.
- Ham rigs of the 1960s and 1970s usually had restricted-range
pi-nets which were easier to adjust, but sometimes required an
external matching device.
- Ham rigs of the 1980s and later usually have solid-state finals and
no adjustment - and usually require an external matching device.

73 de Jim, N2EY

wrote in
oups.com:
Some may tell you that all it takes to tune up a tube
transmitter is to "peak the grid and dip the plate", but
that's simply not correct. Tuneup procedures vary
according to rig design and you have to be specific.
Of course once you get the hang of it, the procedure
rapidly becomes second nature.

I enjoy twiddling knobs, kind of the same way I like a manual
transmission. 8^)

It's a question of skill vs. automation.

I've always wanted to know just what was going on in what I was
operating. I at least like the option betwen automatic operation and
manual. Skills can never hurt.


What specific hollowstate rigs are you considering?

* * Last year at Dayton I purchased a 40 and 80 meter Heathkit single
* * Bander as a learning tool - they are pretty simple. I restored
the * * 80 meter unit, and will start on the 40 meter one sometime.

I think you mean the Heath HW-12 and HW-22, or the later
A models of the same rigs.

They are from the early-to-mid 1960s, and have very limited
matching range. They are really only meant to match a 50
ohm load. Note that there isn't even a LOADING control on
them.

That would be the units with one exception. More on that later..


The Single Banders were Heath's answer to the "SSB is too
expensive" idea. Every possible simplification and economy
measure was used in them, yet the result is a usable 100 W
class SSB transceiver for one HF ham band.

The simplicity was what attracted me to them. No filters, nonotch,
no pbt, no RIT, no - well you get it.



Note that the
75 meter one stops at 3.8 MHz. Heath figured that by
simplifying the output pi network to the most extreme degree,
they could save a few dollars. Coming up with a 50 ohm
antenna was the ham's problem.

The 75 meter rig I have tunes to 4 MHz. It's also a HW22a, probably a
later mod. But all that simplicity is a good thing for a lad raised
mostly on integrated circuits! 8^)


I am now
* * looking at a Kenwood TS-830S. It's a hybrid, with tube finals. I
* * really like it so far, although I don't see it replacing my
IC-761.

That's a pretty good rig for its era. The matching range is limited
but it will handle 2:1 SWR without problems IMLE.

I have been pretty impressed so far. The receiver seems pretty hot,
certainly the sound is *good*. I'm listening to it right now, and it is
simply very legible. Tuning is only one speed, and a tad fast. Seems
strange just having SSB and CW, but overall I think I'll keep it.



I am hooked on computer control of the newer rig - sometimes!
Other times I just like that retro aspect.

One of the great things about amateur radio today is that we can
use a wide variety of technologies for the same or similar purposes.


I find it ironic that the evolution of the "state of the art" has come
full circle in about a half-century, at least in HF/MF:

- Ham rigs of the 1950s usually had wide range pi-nets which required
adjustment, but would match almost anything without an external
device.
- Ham rigs of the 1960s and 1970s usually had restricted-range
pi-nets which were easier to adjust, but sometimes required an
external matching device.
- Ham rigs of the 1980s and later usually have solid-state finals and
no adjustment - and usually require an external matching device.

And that is what I'm thinking about with regards to new rigs with
an internal tuner that has both balanced and unbalanced capabilities as a
natural evolution. There are a lot of Hams that don't have the ability to
put up towers and beams, and are looking at a wire antenna for a while. I
think its time for that

- 73 de Mike KB3EIA -

On Mar 5, 3:26 am, Mike Coslo wrote:
wrote groups.com:


The simplicity was what attracted me to them. No filters, nonotch,
no pbt, no RIT, no - well you get it.

Note that the
75 meter one stops at 3.8 MHz. Heath figured that by
simplifying the output pi network to the most extreme degree,
they could save a few dollars. Coming up with a 50 ohm
antenna was the ham's problem.

The 75 meter rig I have tunes to 4 MHz. It's also a HW22a, probably a
later mod. But all that simplicity is a good thing for a lad raised
mostly on integrated circuits! 8^)

The 75m transceiver is the HW-12A. It runs 3.8-4.0 MHz. That's all
the phone band there was back when the rig was produced. There's a
mod in one of the mags--CQ, I think--that puts in a fixed silver mica
cap with a little trimmer cap in parallel for making the thing work on
both 3.8-4.0 and 3.7-3.9 MHz at the flip of a mini-toggle switch.
That'd give you a bit more room to roam.

I am now
looking at a Kenwood TS-830S. It's a hybrid, with tube finals. I
really like it so far, although I don't see it replacing my
IC-761.

That's a pretty good rig for its era. The matching range is limited
but it will handle 2:1 SWR without problems IMLE.

I have been pretty impressed so far. The receiver seems pretty hot,
certainly the sound is *good*. I'm listening to it right now, and it is
simply very legible. Tuning is only one speed, and a tad fast. Seems
strange just having SSB and CW, but overall I think I'll keep it.

In it's era, the TS-830 was somewhat of a DXer's and contester's dream
machine.
That receiver has an extra filter slot for cascading filters. One can
still buy after market filters for it.

Dave K8MN

wrote:
On Mar 5, 3:26 am, Mike Coslo wrote:
wrote groups.com:


The simplicity was what attracted me to them. No filters, nonotch,
no pbt, no RIT, no - well you get it.

Note that the
75 meter one stops at 3.8 MHz. Heath figured that by
simplifying the output pi network to the most extreme degree,
they could save a few dollars. Coming up with a 50 ohm
antenna was the ham's problem.
The 75 meter rig I have tunes to 4 MHz. It's also a HW22a, probably a
later mod. But all that simplicity is a good thing for a lad raised
mostly on integrated circuits! 8^)

The 75m transceiver is the HW-12A. It runs 3.8-4.0 MHz. That's all
the phone band there was back when the rig was produced.

Thanks for the correction Dave. I should have looked at the back of the
unit when I was composing my email



There's a
mod in one of the mags--CQ, I think--that puts in a fixed silver mica
cap with a little trimmer cap in parallel for making the thing work on
both 3.8-4.0 and 3.7-3.9 MHz at the flip of a mini-toggle switch.
That'd give you a bit more room to roam.

Now there is serendipity for ya! I was trying to align the thing, and
having some trouble with the top end. And the unit had this extra switch
on the front. Since I couldn't find the schematic for the "a" version, I
wasn't sure if that switch was part of th ea version or not. Preliminary
looks made me think that it might have been something to lower the
frequency down to the CW portion of the band. But it looks as if my rig
has that mod .


In it's era, the TS-830 was somewhat of a DXer's and contester's dream
machine.
That receiver has an extra filter slot for cascading filters. One can
still buy after market filters for it.

I can believe that it was very popular. The hybrid concept is
interesting. I especially like that you can turn the tubes off if you
just want to listen.

- 73 de Mike KB3EIA -

On Mar 5, 3:20 pm, Michael Coslo wrote:
wrote:
On Mar 5, 3:26 am, Mike Coslo wrote:

The 75m transceiver is the HW-12A. It runs 3.8-4.0 MHz. That's all
the phone band there was back when the rig was produced.

Thanks for the correction Dave. I should have looked at the back of the
unit when I was composing my email

Not a problem. I'm fairly familiar with the series since I ran them
mobile for a number of years.

There's a

mod in one of the mags--CQ, I think--that puts in a fixed silver mica
cap with a little trimmer cap in parallel for making the thing work on
both 3.8-4.0 and 3.7-3.9 MHz at the flip of a mini-toggle switch.
That'd give you a bit more room to roam.

Now there is serendipity for ya! I was trying to align the thing, and
having some trouble with the top end. And the unit had this extra switch
on the front. Since I couldn't find the schematic for the "a" version, I
wasn't sure if that switch was part of th ea version or not. Preliminary
looks made me think that it might have been something to lower the
frequency down to the CW portion of the band. But it looks as if my rig
has that mod .

If I run across the mod, I'll forward a scan of the information to
you. There was another easy mod which padded the carrier oscillator
frequency in order to roll off some of the annoying high frequency
hiss on receiver, while adding fullness to the transmitted audio. It
had the added benefit of more carrier output for tune up.
Your HW-12A may have that mod as well.

In it's era, the TS-830 was somewhat of a DXer's and contester's dream
machine.
That receiver has an extra filter slot for cascading filters. One can
still buy after market filters for it.

I can believe that it was very popular. The hybrid concept is
interesting. I especially like that you can turn the tubes off if you
just want to listen.

The '830 doesn't get points for being an early hybrid, but it does get
points for having that cascaded filter availability. The early
Hybrids were rigs like the Yaesu FT-101 and variants along with the
Kenwood TS-520 and TS-820. Drake used a hybrid design in the T4-XC/R4-
C transmitter/receiver pair but there was a mix of tubes/solid state
devices in the receiver. The Drake 2-C receiver might have been the
earliest hybrid design amateur receiver.

Dave K8MN