Transmitting tubes!
Dino Darling
I need to learn more about tubes and I need YOUR help. It is my
understanding that you can use TV sweep tubes for transmitters BUT that
this parctice is NOT recommended. What is a good RF tube capable of
100 watts output and what books do you suggest?
I think Yaesu used the 6146 tube. Is this a good choice?
My goal is to BUILD my own transmitter/receiver and to put the Amateur
back in radio. THANKS!!!
Dino Darling KC6RIX
di...@deltanet.com
WB3U
Heathkit, Collins and many others used the 6146 and its variants long
before the Japanese entered the market. Yes, it's a good, rugged
design and probably the most appropriate to the 100 watt output level.
Actually, a pair of 6146B's will deliver about 120 watts in class AB1
(SSB/CW) and about 160-170 watts in class C (CW only).
There were a number of 6146 designs in ARRL Handbooks during the 60's
and early 70's. The '72 Handbook described a heterodyne-type CW
transmitter with (2) 6146B's that included a built-in T-R switch for
QSK. The transmitter was a hybrid (only the driver and finals were
tube-type), but it covered 160 thru 10 meters (no WARC).
Incidentally, as much as I enjoy the glow of tubes, I wouldn't
personally build a transmitter with a tube-type final at this power
level. If you do, be prepared to scrounge *many* parts at hamfests,
or to end up with a project that will be much more expensive than its
solid-state counterpart. One option in this regard might be to buy a
used Heath HW-101 or similar with the matching AC power supply and
scrap the whole thing for parts.
However you decide to do this, I recommend that you become very
familiar with the potential cost of the entire project (and determine
whether parts necessary to complete it are even available) before you
spend a nickel. Commercial tube-type transmitters are plentiful on
the used market at reasonable prices. A homebrew version could easily
cost twice as much and have little or no resale value.
73,
Jack WB3U
Dana Myers
WB3U <ja...@pinetree.microserve.com> wrote:
[...]
>Heathkit, Collins and many others used the 6146 and its variants long
>before the Japanese entered the market. Yes, it's a good, rugged
>design and probably the most appropriate to the 100 watt output level.
>Actually, a pair of 6146B's will deliver about 120 watts in class AB1
>(SSB/CW) and about 160-170 watts in class C (CW only).
^^^^^^^^^^^^^^^^
Don't forget FM, FSK and plate modulated AM ;-).
--
* Dana H. Myers KK6JQ, DoD#: j | Views expressed here are mine and should *
* (310) 348-6043 | not be interpreted or represented as *
* Dana....@West.Sun.Com | those of Sun Microsystems, Inc. *
K2EK
Darling) writes:
> What is a good RF tube capable of
>100 watts output and what books do you suggest?
>
>I think Yaesu used the 6146 tube. Is this a good choice?
>
>
EVERYONE used a pair of 6146Bs with a 12BY7 driver... well, almost
everyone.
Yes, that will make a good lineup. You can also use a pair of 807 or 1625
(the 12.6v equivalent) if you want to include the nostalgia element. For
real fun, get hold of a 6L6 or 6DQ6... Either makes a nice 1 tube
transmitter in the 15-25w range.
TV sweep tubes will work. One of my favorite activities was finding a
junked TV by the curb on the way home from school and making a
transmitter out of it by dinner time. The only "external" parts needed
were a couple air variable capacitors, some wire and a crystal. Get hold
of any ARRL handbook from the 60s or early 70s. They are loaded with
ideas you can try and the tube tables are indespensible.
Bill K2EK
Edward Kravitz
some for a few of their xmtrs, and had good results ! 6146's are quite
common however. I recently got 7 working ones in a five dollar box of
"junk parts" .
Good luck
Ed K . KB2NSP
Nan Gwa
writes:
>Subject: Re: Transmitting tubes!
>From: Wayne Glover <wgl...@awod.com>
>Date: 31 Mar 1996 07:03:31 GMT
>
>>>
>>>I think Yaesu used the 6146 tube. Is this a good choice?
>>>
>
>Actually the Yaesu FT101B through the FT101E used a pair of 6JS6C sweep
>tubes driven by a 12BY7A.
>
>Not the best transmitter tubes in the world, but the story I heard was
>that in the '50s-'70s rf tubes like the 6146s were not available to the
>Japanese,(embargos or whatever) so they used whatever they had.
>
>73s
>
>Wayne, KI$XR
>
>
My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
Tube Linear Amplifier", states, "Because only low-duty-cycle transmission
is suitable for sweep tubes operated at high power levels, this amplifier
cannot be used for a-m, fm, or RTTY service." Aside from problems the
Japanese may have had, why would anyone have wanted to make a sweep
tube amplifier anyway?
Tom Donaly KA6RUH
William W Janssen
>In article <4jlao4$9...@harbour.awod.com>, Wayne Glover <wgl...@awod.com>
>writes:
>
>>Subject: Re: Transmitting tubes!
>>From: Wayne Glover <wgl...@awod.com>
>>Date: 31 Mar 1996 07:03:31 GMT
>>
>>>>
>>>>I think Yaesu used the 6146 tube. Is this a good choice?
>>>>
>>
>>Actually the Yaesu FT101B through the FT101E used a pair of 6JS6C sweep
>>tubes driven by a 12BY7A.
>>
>>Not the best transmitter tubes in the world, but the story I heard was
>>that in the '50s-'70s rf tubes like the 6146s were not available to the
>>Japanese,(embargos or whatever) so they used whatever they had.
>>
>>73s
>>
>>Wayne, KI$XR
>>
>>
>Japanese may have had, why would anyone have wanted to make a sweep
>tube amplifier anyway?
>
>Tom Donaly KA6RUH
>
equipment. They were cheep also.
Bill K7NOM
W8JI Tom
writes:
>My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
>Tube Linear Amplifier", states, "Because only low-duty-cycle transmission
>is suitable for sweep tubes operated at high power levels, this amplifier
>cannot be used for a-m, fm, or RTTY service." Aside from problems the
>Japanese may have had, why would anyone have wanted to make a sweep
>tube amplifier anyway?
>
>Tom Donaly KA6RUH
>
>
Hi Tom,
Sweep tubes used to be cheap tubes. 6146's cost around $8 each wholesale,
and sweep tubes were on a buck or two. Cost is always an issue that drive
component selection.
The Japanese also used sweep tubes because they make great effort to avoid
out of country suppliers. They have great fraternalism and unity in
supporting their own workers and countrymen.
6146's also will not work in grounded grid RF amplifier applications.
Sweep tubes were the ONLY cheap tube suitable for grounded grid RF
applications.
Sweep tubes now cost more than transmitting tubes, so the cost advantages
have disappeared. A 572B now costs less than a 6JE6.
73 Tom
David Feldman
>In article <4jlao4$9...@harbour.awod.com>, Wayne Glover <wgl...@awod.com>
>My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
>Tube Linear Amplifier", states, "Because only low-duty-cycle transmission
>is suitable for sweep tubes operated at high power levels, this amplifier
>cannot be used for a-m, fm, or RTTY service." Aside from problems the
>Japanese may have had, why would anyone have wanted to make a sweep
>tube amplifier anyway?
In the 1960s and 70s the sweep tubes were probably cheapest in terms of
$ per watt of plate dissipation, save maybe for surplus 807/1625 types.
According to my RCA tube book the 6LQ6 series specifically states that
it could do 200 watts plate dissipation for some short maximum duration,
15 seconds as I recall. No other sweep tube was specified in this particular
way, nor the 6146. Sweep tubes are usually specified for "pulse" operation.
SSB (particularly uncompressed) has a low duty cycle (not as low as pulse,
but lower than CW/AM/etc.) I don't think the 6146 series ever was spec'd for
pulse operation.
Also most of the larger sweep tubes are rated for about 1KV maximum DC plate
voltage (the 6146B max DC plate voltage is 750). The higher max plate voltage
would make it a bit easier to design a pi-network output section as total
plate impedance would be higher for the sweep tubes for the same power level,
say in a 1kw input type amplifier, and you still wouldn't need to have very
much spacing in the plate tuning capacitor because you're not dealing with
really high voltages like in a 572 or 3-500Z amp.
Nowadays it would be nuts because the sweep tubes are mostly out of production
and remaining stock is expen$ive, particularly if you're going to design
a new amplifier for commercial production.
73 Dave WB0GAZ d...@netcom.com
Claude Frantz
>EVERYONE used a pair of 6146Bs with a 12BY7 driver... well, almost
>everyone.
But the 6CL6 is a more robust driver than the 12BY7.
--
Claude
(cla...@bauv106.bauv.unibw-muenchen.de)
The opinions expressed above represent those of the writer
and not necessarily those of her employer.
Tom Skelton
>==========William W Janssen, 3/31/96==========
>
>nan...@aol.com (Nan Gwa) wrote:
>>In article <4jlao4$9...@harbour.awod.com>, Wayne Glover
><wgl...@awod.com>
>>writes:
>>
>>>From: Wayne Glover <wgl...@awod.com>
>>>Date: 31 Mar 1996 07:03:31 GMT
>>>
>>>>>
>>>>>I think Yaesu used the 6146 tube. Is this a good choice?
>>>>>
>>>
>>>Actually the Yaesu FT101B through the FT101E used a pair of
6JS6C sweep
>>>tubes driven by a 12BY7A.
>>>
>>>Not the best transmitter tubes in the world, but the story I
heard was
>>>that in the '50s-'70s rf tubes like the 6146s were not
>available to the
>>>Japanese,(embargos or whatever) so they used whatever they had.
>>>
>>>73s
>>>
>>>Wayne, KI$XR
>>>
>>>
>>Japanese may have had, why would anyone have wanted to make a sweep
>>tube amplifier anyway?
>>
>>
>Sweep tubes can handle larg PEAK currents. Ideal for low duty cycle
>equipment. They were cheep also.
>
>Bill K7NOM
>
It wasn't just the Japanese. I can't count the number of times
we replaced
the sweep tube finals in a Drake T4XB at the Clemson U club
station. I think
it also used a pair of 6JS6C's, but I'm probably wrong. When we
got a Kenwood
TS530S with 6146B's, even with fairly regular contesting, Dx'ing
and general usage,
they kept going and going and going...... Of course, by then
the RTTY enthusiasts
had graduated. :-)
73, Tom WB4iUX
Clemson U, '76, '82
Tom.S...@ColumbiaSC.ATTGIS.COM
or
WB4...@AOL.COM
Monty Wilson
>My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
>Tube Linear Amplifier", states, "Because only low-duty-cycle transmission
>is suitable for sweep tubes operated at high power levels, this amplifier
>Japanese may have had, why would anyone have wanted to make a sweep
>tube amplifier anyway?
My dad's Drake TR-3 transceiver uses three sweep tubes in parallel,
and it does use them on AM, but they pulled a trick to keep the
duty cycle down. They suppressed the carrier and screen-grid-
modulated the tubes so your wattmeter looks like you're talking on
sideband, but when the sidebands are present the carrier is also,
making it possible to copy you on an AM receiver. Of course, a
REAL AMer would tell you you don't sound too good...
--
.........Monty.
mwi...@bangate.compaq.com
David Feldman
>nan...@aol.com (Nan Gwa) wrote:
>>My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
>My dad's Drake TR-3 transceiver uses three sweep tubes in parallel,
>and it does use them on AM, but they pulled a trick to keep the
>duty cycle down. They suppressed the carrier and screen-grid-
>modulated the tubes so your wattmeter looks like you're talking on
>sideband, but when the sidebands are present the carrier is also,
>making it possible to copy you on an AM receiver. Of course, a
>REAL AMer would tell you you don't sound too good...
Drake calls this "controlled carrier AM". I think what's really happening
is that the carrier level into the finals tracks the modulation envelope,
so when the signal is only lightly modulated (i.e., less power into the
sidebands), the carrier level is reduced accordingly, so that the carrier-
to-peak-modulation-power level is held more in line. It definately gives
you lower average plate dissipation (unless you're also using audio
compression) and it is still audiable on a regular AM receiver (altho the
RF-derived "S" meter on an old style AM receiver will now move at a syllabic
rate, rather than hold steady). It's kind of an interesting scheme and the
only drawback I can see is that the receiving end might perceive a lower
signal/noise ratio during periods of low modulation.
No other HF transceiver (even modern solid state ones) seem to work this way.
73 Dave WB0GAZ d...@netcom.com
Randall Bradley
Sweep tubes were cheAp,
while birds, birdies go cheEp.
Minor points to be sure, but the speeling on the
net culd be bedder.
_-_randy_-_
Tom Bruhns
: What is a good RF tube capable of 100 watts output ...?
I'm surprised nobody (until now) has mentioned the 811A as a
possibility in this power range. It's capable of a bit more
power than this, but it should run 100 watts out pretty
comfortably.
--
Cheers,
Tom
to...@lsid.hp.com
Edward Kravitz
used in other early rigs , ie: Heathkit DX-35,40,and 60 and Knight T-
60, 150
Hallicrafters HT-40. Check em out.
David S.A. Stine
>My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
>is suitable for sweep tubes operated at high power levels, this amplifier
>cannot be used for a-m, fm, or RTTY service." Aside from problems the
>Japanese may have had, why would anyone have wanted to make a sweep
>tube amplifier anyway?
>
Because TV sweep tubes have humongous cathode emission levels -- ie, even
tho the plate dissapation might be only 25 watts in ICAS, the tube's
cathode might well be able to supply enough current to allow for peak power
levels of well over 100W per tube.
As a result, if you were producing a final which was going to be used in a
[relatively] compact unit, you could get your power density waaaay up
there, compared to how much space it would have taken you if you were using
"real" tubes for the job.
Look at the Swan line of transceivers -- they used sweep tubes and were
very popular for mobile SSB work in the late 70's and early 80's.
So what if the key-down power level was only 15% of what the SSB rating
was? Were you really going to use it for CW? RTTY? How many people used to
work RTTY when you were using 026's and model 19's? FM? On HF? Nah. AM was
well on its way out the door by the late 70's, so sweep tubes were a pretty
nifty idea on how to get SSB equipment down to a tolerable size for mobile
work. In that era, SSB was "the thing" in commercial equipment.
Transmitters I've owned (or still own) which use sweep tubes:
- Hammarlund HX-50 (6DQ5) (not exactly a mobile unit)
- Swan 260, 270, 500 (very usable for mobile work, and I used the 260
for mobile work *very* well during college)
So sweep tubes have their uses. You just have to understand that they're
while they're cheap, small and high-output, they don't forgive key-down
applications.
dsa
WB3U
>I'm surprised nobody (until now) has mentioned the 811A as a
>possibility in this power range. It's capable of a bit more
>power than this, but it should run 100 watts out pretty
>comfortably.
Good idea! I guess the temporary absence of the 811A from the market
still tends to displace it as a choice for transmitters. I don't
usually think about using it as a grid-driven final, although there's
no reason not to.
At 100 watts out, an 811A would last almost forever. It's also
cheaper than a pair of 6146B's.
73,
Jack WB3U
KF9CM
> Dino Darling (di...@deltanet.com) wrote:
> : What is a good RF tube capable of 100 watts output ...?
>
> possibility in this power range. It's capable of a bit more
> power than this, but it should run 100 watts out pretty
> comfortably.
>
> Cheers,
> Tom
> to...@lsid.hp.com
>
>>>>
I concur The 811A is the best bang for the buck ($14 new). Operating
classs B Grounded Grid the output is aprox, 150 watts out with 15 watts
drive.
Good luck Gary KF9CM
michael silva
writes:
>>Aside from problems the
>>Japanese may have had, why would anyone have wanted to make a sweep
>>tube amplifier anyway?
>>
>>Tom Donaly KA6RUH
>>
>Sweep tubes can handle larg PEAK currents. Ideal for low duty cycle
>equipment. They were cheep also.
Yep, and yep (emphasis on the 'were'). It's interesting to look at an
old sweep tube like the 6BG6 (an 807 with an octal base) and compare it
to a more modern tube of about the same plate dissipation. The modern
sweep tube will have a cathode 2-3 times larger. -Lots- of peak
current capability.
73,
Mike, KK6GM
Barbara Fehner
modulation. He developed it for mobile use in the days of 6V. car
batteries and dynamotors inorder to reduce power consumption. A switch
controlled the screen grid clamping voltage allowing either controlled
carrier or normal screen grid modulation. I used the system with an
ARC5 transmitter in the early 50's and it worked great with just a
little non-linearity in the modulation.
Barbara KK6IB
E-Mail: feh...@cts.com
___________________________________________________________________
d...@netcom.com (David Feldman) wrote:
>In article <Dp76q...@twisto.eng.hou.compaq.com> Monty Wilson <mwi...@bangate.compaq.com> writes:
>>nan...@aol.com (Nan Gwa) wrote:
>>>My venerable old 1973 ARRL Handbook, in a section entitled "A Sweep
>
WB3U
>This system was developed in 1950 by Bob Carter and was called Carter
>modulation. He developed it for mobile use in the days of 6V. car
>batteries and dynamotors inorder to reduce power consumption. A
>switch controlled the screen grid clamping voltage allowing either
>controlled carrier or normal screen grid modulation. I used the
>system with an ARC5 transmitter in the early 50's and it worked great
>with just a little non-linearity in the modulation.
There were some solid state (homebrew) designs in the 60's or early
70's that did the same thing. The amount of carrier varied with
modulation and would fall to zero with no audio input.
73,
Jack WB3U