Thanks to everyone for the encouragement. Next step is to make the conversion
to this little power supply, then tweak that oscillator plate voltage etc. and
see if I can get it on the air. I have already decided not to worry about
keeping this thing "original", eg. will be putting in a new power plug, key
jack, and coax connector etc. I am sure I will have many more questions as I
proceed and will keep you posted with the progress and inevitable mysteries
that will need solving....

Why do you think the regulated dc on the filaments makes such a difference?
Closer to the original battery powered situation? Would that be true for any
old tube transmitter? Or because these particularly were originally designed to
run on 28 volt DC.


Bill, K6TAJ


COLIN LAMB wrote:

The ARC-5 transmitter is one of the great piece of electronics out of WWII.
As a kid, my first transmitter was an ARC-5 bought from JJ Glass of Los
Angeles for about $5.95. It was brand new and a beauty to behold. Getting
it working right will teach you everything that you need to know about
electronics (well as of 1957 anyway).

I was able to get mine to key nicely with no chirp at all. I still have a
wall full of them, they are nice to look at. You should be able to find a
schematic on the internet. I found that adjusting the oscillator plate
voltage to the individual transmitter could help solve a lot of problems and
regulated dc on the filaments does wonders, too. They will run 100 watts
without too much strain, although the power supplyis often twice the size of
the transmitter. But, they also run qrp on a much smaller supply and lower
voltage.

Have fun, Colin K7FM

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Question: "Why do you think the regulated dc on the filaments makes such a
difference? Closer to the original battery powered situation? Would that be
true for any
old tube transmitter? Or because these particularly were originally designed
to run on 28 volt DC."

The oscillator obtains feedback by tapping the cathode up on the coil. This
allows the ac on the filaments to modulate the oscillator slightly. A
filament winding was added to reduce this effect, but it does not. Some
ARC-5s have hum modulation - especially when multiplying to 10 meters.

Also, a change in filament voltage causes drift of the vfo. When we were
converting these rigs 50 years ago, it was difficult to get 24 volts
regulated. Today it is a snap. It may be easier to get a regulated 13.8
volts (or 12 volts or anything in between).

In my early hamshack, the test for stability was to switch on the heater and
listen for drift about 30 seconds later. Even the heralded SX-101 would
drift mightily on 10 meters when I did that trick - until I regulated the
filament voltage on the oscillator using the separate transformer that
always kept the heater on.

73, Colin K7FM










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zeno wrote:

I have already decided not to worry about
keeping this thing "original", eg. will be putting in a new power plug, key
jack, and coax connector etc....

It is certainly your radio and you can do as you wish,
but I urge you to reconsider; this isn't a old Craig CB rig
or and Eico 753. This radio has historic significance.

Extensive modification is needless
and will turn your historic relic into a junkbox nothing.
You can get the rig on the air with a good signal
without drilling a single hole or chopping out anything.
It's as simple as disconnecting
one wire and adjusting one relay contact.
If you need pins to fit the power connector on the back,
send me your address and I'll send you some.
Moreover, if you do the butchery to put the filiments on
12 volts AC, you are defeating part of the engineering solution
designed to keep the rigs stable.
My rigs are original design and work great with
good power out and little or no chirp.

First- throw out ALL those "conversion" articles from
the 50s, 60s and 70s. The first ones were written by
people who knew nothing about getting these rigs going
and the rest just parroted what the first wrote.
I can't tell you how many rigs went from "war relic"
to "trash can" because of some conversion "author."
The rigs are NOT TVI machines, chirp factories,
harmonic generators or any of the other myths
you've heard. These were born out of people flailing
around blindly without any understanding of how
the rig was designed to work.

I have lots of information on how to get these going
with little work and no irreversable mods.
I'm headed to work. If anyone cares to read them,
I will post them when I get home this evening.

73 DE Dave Stinson AB5S

The BC-459-A found at the dump, is a bare aluminum Western Electric. It has been
already modified, the plug was already changed, a key jack put in the back, and
a bunch of wiring mods which are incomprehensible to me. It is missing the 1629,
the 1626, and the Xtal. I have since picked up another BC-459 (black) which
seems to be internally unmodified and complete with all tubes and Xtal (8870
KC), although it is missing the bottom plate and the cover. It is a black, but
It notice the case parts from the bare aluminum one would fit to this black one.
I was also given an old homebrew power supply which still works and was
apparently built to the specs that are described in the ARRL article about
converting the Arc 5 for Novice use. This power supply has a male octal plug
with wiring that exactly corresponds to this article, eg. it has the 12.6 V
filament and a 6.3 V filament as well as all the B+ voltages as per the article.
Yes this is the article which describes how to make an outboard crystal
controlled oscillator with 6AG7 tube and which then plugs into the Xtal socket
of the Arc 5. The modification is such that the Arc 5 can be put back to VFO
operation simply by removing this outboard novice xtal unit and putting back the
original Xtal.

The wiring in this first BC-459 is a mess and has been hacked up, It was going
to use this unit for parts, at least use the bottom plate and the case, even
though it is bare aluminum and the better unit I have is black. The better unit,
as stated, seems to be internally unmodified, so doing the mods in this article
would be more straight forward.

However, having now posted to this forum and having received the various
suggestions, I am wondering what the best path might be here. First off, I do
not understand how one would use the original plug in the back since I have
never seen an original male fitting available anywhere. Secondly, I am wondering
what kind of other power supply one would use to keep everything in its original
context. In short I am wondering what is the best, and most practical way to get
this thing operating. The only information on converstion that I have at this
point is the the article which appears on the ARRL site "Coverting Surplus
Transmitter for Novice Use" even though I was not going to build the outboard
xtal unit as suggested. I would be interested in seeing other, perhaps superior,
methods for putting this gear to use. Really, how bad is this particular article
and its mod suggestions? It has been suggested that the addition of some
regulation on the oscillator voltage would solve the problem of chirp/drift etc.

I would be interested in the type of mods and power supplies that you are all
using which have proven successful before I proceed any further.

I am assuming there are plenty of these units preserved as museum pieces
already, I was more interested in using it without necessarily turning the shack
into a complete ww2 cockpit.

Bill, K6TAJ




David Stinson wrote:

zeno wrote:

I have already decided not to worry about
keeping this thing "original", eg. will be putting in a new power plug, key
jack, and coax connector etc....

It is certainly your radio and you can do as you wish,
but I urge you to reconsider; this isn't a old Craig CB rig
or and Eico 753. This radio has historic significance.

Extensive modification is needless
and will turn your historic relic into a junkbox nothing.
You can get the rig on the air with a good signal
without drilling a single hole or chopping out anything.
It's as simple as disconnecting
one wire and adjusting one relay contact.
If you need pins to fit the power connector on the back,
send me your address and I'll send you some.
Moreover, if you do the butchery to put the filiments on
12 volts AC, you are defeating part of the engineering solution
designed to keep the rigs stable.
My rigs are original design and work great with
good power out and little or no chirp.

First- throw out ALL those "conversion" articles from
the 50s, 60s and 70s. The first ones were written by
people who knew nothing about getting these rigs going
and the rest just parroted what the first wrote.
I can't tell you how many rigs went from "war relic"
to "trash can" because of some conversion "author."
The rigs are NOT TVI machines, chirp factories,
harmonic generators or any of the other myths
you've heard. These were born out of people flailing
around blindly without any understanding of how
the rig was designed to work.

I have lots of information on how to get these going
with little work and no irreversable mods.
I'm headed to work. If anyone cares to read them,
I will post them when I get home this evening.

73 DE Dave Stinson AB5S

The BC-459-A found at the dump, is a bare aluminum Western Electric. It has been
already modified, the plug was already changed, a key jack put in the back, and
a bunch of wiring mods which are incomprehensible to me. It is missing the 1629,
the 1626, and the Xtal. I have since picked up another BC-459 (black) which
seems to be internally unmodified and complete with all tubes and Xtal (8870
KC), although it is missing the bottom plate and the cover. It is a black, but
It notice the case parts from the bare aluminum one would fit to this black one.
I was also given an old homebrew power supply which still works and was
apparently built to the specs that are described in the ARRL article about
converting the Arc 5 for Novice use. This power supply has a male octal plug
with wiring that exactly corresponds to this article, eg. it has the 12.6 V
filament and a 6.3 V filament as well as all the B+ voltages as per the article.
Yes this is the article which describes how to make an outboard crystal
controlled oscillator with 6AG7 tube and which then plugs into the Xtal socket
of the Arc 5. The modification is such that the Arc 5 can be put back to VFO
operation simply by removing this outboard novice xtal unit and putting back the
original Xtal.

The wiring in this first BC-459 is a mess and has been hacked up, It was going
to use this unit for parts, at least use the bottom plate and the case, even
though it is bare aluminum and the better unit I have is black. The better unit,
as stated, seems to be internally unmodified, so doing the mods in this article
would be more straight forward.

However, having now posted to this forum and having received the various
suggestions, I am wondering what the best path might be here. First off, I do
not understand how one would use the original plug in the back since I have
never seen an original male fitting available anywhere. Secondly, I am wondering
what kind of other power supply one would use to keep everything in its original
context. In short I am wondering what is the best, and most practical way to get
this thing operating. The only information on converstion that I have at this
point is the the article which appears on the ARRL site "Coverting Surplus
Transmitter for Novice Use" even though I was not going to build the outboard
xtal unit as suggested. I would be interested in seeing other, perhaps superior,
methods for putting this gear to use. Really, how bad is this particular article
and its mod suggestions? It has been suggested that the addition of some
regulation on the oscillator voltage would solve the problem of chirp/drift etc.

I would be interested in the type of mods and power supplies that you are all
using which have proven successful before I proceed any further.

I am assuming there are plenty of these units preserved as museum pieces
already, I was more interested in using it without necessarily turning the shack
into a complete ww2 cockpit.

Bill, K6TAJ




David Stinson wrote:

zeno wrote:

I have already decided not to worry about
keeping this thing "original", eg. will be putting in a new power plug, key
jack, and coax connector etc....

It is certainly your radio and you can do as you wish,
but I urge you to reconsider; this isn't a old Craig CB rig
or and Eico 753. This radio has historic significance.

Extensive modification is needless
and will turn your historic relic into a junkbox nothing.
You can get the rig on the air with a good signal
without drilling a single hole or chopping out anything.
It's as simple as disconnecting
one wire and adjusting one relay contact.
If you need pins to fit the power connector on the back,
send me your address and I'll send you some.
Moreover, if you do the butchery to put the filiments on
12 volts AC, you are defeating part of the engineering solution
designed to keep the rigs stable.
My rigs are original design and work great with
good power out and little or no chirp.

First- throw out ALL those "conversion" articles from
the 50s, 60s and 70s. The first ones were written by
people who knew nothing about getting these rigs going
and the rest just parroted what the first wrote.
I can't tell you how many rigs went from "war relic"
to "trash can" because of some conversion "author."
The rigs are NOT TVI machines, chirp factories,
harmonic generators or any of the other myths
you've heard. These were born out of people flailing
around blindly without any understanding of how
the rig was designed to work.

I have lots of information on how to get these going
with little work and no irreversable mods.
I'm headed to work. If anyone cares to read them,
I will post them when I get home this evening.

73 DE Dave Stinson AB5S

Question: "Why do you think the regulated dc on the filaments makes such a
difference? Closer to the original battery powered situation? Would that be
true for any
old tube transmitter? Or because these particularly were originally designed
to run on 28 volt DC."

The oscillator obtains feedback by tapping the cathode up on the coil. This
allows the ac on the filaments to modulate the oscillator slightly. A
filament winding was added to reduce this effect, but it does not. Some
ARC-5s have hum modulation - especially when multiplying to 10 meters.

Also, a change in filament voltage causes drift of the vfo. When we were
converting these rigs 50 years ago, it was difficult to get 24 volts
regulated. Today it is a snap. It may be easier to get a regulated 13.8
volts (or 12 volts or anything in between).

In my early hamshack, the test for stability was to switch on the heater and
listen for drift about 30 seconds later. Even the heralded SX-101 would
drift mightily on 10 meters when I did that trick - until I regulated the
filament voltage on the oscillator using the separate transformer that
always kept the heater on.

73, Colin K7FM










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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04

zeno wrote:

I have already decided not to worry about
keeping this thing "original", eg. will be putting in a new power plug, key
jack, and coax connector etc....

It is certainly your radio and you can do as you wish,
but I urge you to reconsider; this isn't a old Craig CB rig
or and Eico 753. This radio has historic significance.

Extensive modification is needless
and will turn your historic relic into a junkbox nothing.
You can get the rig on the air with a good signal
without drilling a single hole or chopping out anything.
It's as simple as disconnecting
one wire and adjusting one relay contact.
If you need pins to fit the power connector on the back,
send me your address and I'll send you some.
Moreover, if you do the butchery to put the filiments on
12 volts AC, you are defeating part of the engineering solution
designed to keep the rigs stable.
My rigs are original design and work great with
good power out and little or no chirp.

First- throw out ALL those "conversion" articles from
the 50s, 60s and 70s. The first ones were written by
people who knew nothing about getting these rigs going
and the rest just parroted what the first wrote.
I can't tell you how many rigs went from "war relic"
to "trash can" because of some conversion "author."
The rigs are NOT TVI machines, chirp factories,
harmonic generators or any of the other myths
you've heard. These were born out of people flailing
around blindly without any understanding of how
the rig was designed to work.

I have lots of information on how to get these going
with little work and no irreversable mods.
I'm headed to work. If anyone cares to read them,
I will post them when I get home this evening.

73 DE Dave Stinson AB5S