ISSUE NUMBER 77
On A Roll
Following the FCC's 220 mhz decision
by a matter of months, maybe the AM power issue couldn't have come at a
better time. The 220 mhz matter shocked many members of the amateur
radio community out of their apathy into widespread concern that the
FCC is trying to "do in" amateur radio for the benefit of commercial
interests and because the Commission perceives amateur radio as a pain
in the neck to administer. Suddenly, any action by the FCC that is seen
as taking away existing frequencies or operating privileges is treated
as a matter of serious concern. The ARRL has asserted that it will
oppose the loss of any existing amateur privilege. The amateur
community has put the FCC on the defensive, and it looks like the 220
mhz issue is headed to the federal courts. The AM power issue is
made-for-order to become an integral part of this larger issue.
The FCC, acting on no widespread
consensus on the part of the amateur community, arbitrarily decided to
reduce a privilege enjoyed by amateurs in the U.S. for over 60 years:
the privilege to run a fully modulated DSB AM signal with approximately
750 watts of carrier power to the antenna. This is a loss not only to a
handful of AM'ers, but to every amateur radio licensee in the U.S.
Following the FCC's logic that peak envelope power is a relevant
standard for all modes of emission, then every licensed ham in the U.S.
will by definition lose 3 dB of power privilege in June 2, 1990.
A few AM'ers have taken the trouble
to contact their ARRL Division Directors, and the response has so far
been positive. There has not yet been any news of opposition among the
Directors to somehow permanently extending the grandfather clause. A
couple of the Directors have mentioned bringing the matter up at the
Executive Committee meeting. It will be interesting to see what is
reported when the minutes appear in QST.
The most critical need now is for
each and every Director to receive enough input from the membership to
convince them that this is indeed an issue of significant concern. A
momentum presently exists within the amateur community to re-examine
recent decisions by the FCC. All we have to do to join this bandwagon
is to let ourselves be heard in a firm, but positive, responsible
manner. To those AM'ers who don't want to bother to get involved
because they "know" the ARRL and FCC "won't pay any attention," would
you have believed just a month ago that there would now be holes in the
Berlin Wall? The citizens of East Germany have just shown the world
what a potent weapon "people power" can be. The events over Veterans'
Day weekend were like an overdue breath of fresh air at a time when the
news has so long been monotonously negative and depressing. To extend
the analogy, the 1990 AM power reduction is not yet carved in stone.
The division of Berlin was, and now those stones are crumbling. Has the
Director in ARRL Division received any mail over the AM power issue?
BY THE TIME YOU READ THIS, 1990 WILL
BE A MONTH AWAY!
AM Power Issue Discussed at ARRL Executive Committee Meeting
According to the minutes of Meeting
Number 435 held in St. Louis, MO on October 21, "The Executive
Committee discussed, without taking formal action, the status of the
special exemption for AM transmitters in Section 97.313(b) of the
Commission's rules." (see Minute no. 2.6.3, page 54, December 1989 QST)
The good news is that we at least
have a foot in the door. The issue was discussed at the EC meeting,
even though the minutes did not say exactly how the issue was treated
in this discussion. We are now undoubtedly in a very critical period.
All AM'ers who are League members are urgently requested to immediately
write to your Division Directors, or better yet, call them on the
phone, to express your concern over this impending loss of amateur
privileges. All Directors' names, addresses and phone numbers are
listed on page 8 of any recent issue of QST. If you have already
contacted your Director, a follow up communication wouldn't hurt. Now
that the momentum is going, we must not let this matter lose steam and
die. Remember, the AM issue must compete with other current amateur
radio matters such as no-code, the 220 mhz situation, upcoming WARC
conference preparations, etc. Directors who have not yet been contacted
must now hear from the AM community. Those who already have heard from
us must be reminded to keep this issue on the Board's agenda.
Now that the matter has been
mentioned in QST, there is another reason why we must make an extra
effort to keep in touch with the Division Directors. Not all members of
the amateur community share our enthusiasm for AM on the ham bands, and
the Directors are now
likely to begin receiving mail from
some members opposing extension of the grandfather clause, and possibly
urging the elimination of AM altogether. Our chances for success will
be greatly enhanced if any anti-AM mail is overwhelmed by the volume of
mail in support of AM. Since AM'ers are in a minority, especially among
ARRL members, we have to be much more actively involved in our lobbying
efforts than the anti-AM elements within the amateur community.
Drafts Petition For Rulemaking on AM Power Issue
AM P/X has received a copy of the
first draft of a petition for rulemaking requesting the FCC to
reconsider the AM power reduction, from Norm Scott, WB6TRQ, S.P.A.M.
President. A copy was also forwarded to Fried Heyn, WA6WZO, Southwest
Division Director and S.P.A.M. member, requesting his help in getting
this issue on the January, 1990 Board of Directors meeting.
We must emphasize that no petition
has actually been submitted to the FCC as of yet. This is a first
draft, a working paper that is being circulated; S.P.A.M. is seeking
input from the AM community on this issue. Norm suggests that we should
wait until after the ARRL Board of Directors meeting to see if we can
get League support. If not, the final draft petition should be on its
way to the FCC by the end of January, 1990.
The petition is lengthy (12 double
spaced typewritten pages), so we will not attempt to reproduce it in
full this issue, but we are providing a summary. In some instances the
wording has been slightly revised for the sake of conciseness, but we
have made every attempt to accurately report all the main ideas.
The petition will set forth new facts
and analyses to show that the use of the p.e.p. measurement standard to
indicate the interference potential of an AM signal is erroneous. It
will demonstrate to the FCC that the 3 dB power loss will have a
greater impact today because of renewed interest in AM and how many 1
KW AM transmitters will be affected. It will provide evidence that
p.e.p. meters have errors of 3 dB when measuring AM DSB emission. The
petition will suggest changes to standardize the amateur service with
all the other services which use power output limitation to control
The power output standard should be
equal to the amount of recovered audio regardless of the emission used.
The interference potential of an AM signal is 6 dB lower and not equal
to that of the SSB signal with the same output. In fact it is the AM
carrier that has the
most potential for harmful interference. The most
useful purpose of p.e.p. is to measure the capabilities of a linear
amplifier, which is why the standard was developed in the first place.
The greatest interference potential from an AM signal is not the
apparent power in the sidebands. Other services which employ AM control
interference by limiting carrier power output. Probably no other
service is as tightly regulated as AM broadcasting in terms of
interference control. The FCC amended the AM broadcast regulations a
few years ago to allow stations to run 125% positive peak modulation.
In terms of p.e.p. this is a significant power increase, yet stations
running extended positive peak modulation were not required to reduce
their carrier power.
From about 1960, operation of AM in
amateur radio was on the decline. At that rate, by 1990 amateurs would
have stopped using AM. S.P.A.M. members have worked very hard to turn
this situation around. In 1983 S.P.A.M. had 362 members; today there
are over 1000 members and S.P.A.M. is still growing. It is estimated
that there are 423 commercially built one kilowatt AM transmitters and
over 1000 homemade units in operation in the U.S. today (the source of
these statistics is not documented. -Ed.). With an average cost of
$1000 per transmitter, the value of this equipment is $1,420,000 not
including the thousands of hours amateurs have spent building or
restoring this equipment.
The amateur service is the only
service to try to use a p.e.p. standard to control the interference
potential for all 14 authorized emissions. In (14 C.F.R. 2.985)
Measurements Requirements, are listed the methods for measuring the
power output for all type-accepted radio equipment. For transmitters
which have emissions with carrier, the power output is measured by
carrier output. For
transmitters which have suppressed or controlled
carrier, the output is measured by the p.e.p. standard. Of 14
authorized emissions in the amateur radio service, all but two contain
carrier. For emissions with carrier, the carrier power output standard
is the recommended standard in the C.C.I.R. (international
The following amendment is proposed
for the amateur radio power limit:
97.313 (b) No station may transmit
with a transmitter carrier power exceeding 1.5 KW. Emissions with
suppressed carrier are limited to a maximum of 1.5 KW PEP.
The methods and standards proposed in
this petition are not new, but have been around for years, used each
day to control interference in other services. FCC enforcement
personnel are already familiar with the test procedures and would not
need additional training or equipment.
The technical evidence shows that the
interference potential of a 100% modulated AM signal is not equal to
four times the carrier power. The appropriate power standard is based
on the class of emission, and most services follow the C.C.I.R.
guidelines. The use of both carrier power and p.e.p. standards are
justifiable because of the number of authorized emissions in amateur
radio which are subject to the power limit.
At issue is not the fact that only one
percent of amateurs happen to engage in AM operations. An inappropriate
standard is still inappropriate no matter how many amateurs it affects.
The FCC committed itself to a review of the power limit before June,
1990, if it appears to be justified. We have used the time during the
grandfather period to gather the facts and explore other remedies. If
this matter cannot be resolved before June 2, 1990, we request an
extension of the input power standard for AM DSB emission until the
Commission can consider our petition.
S.P.A.M. is seeking input from the AM
community on this issue. Please address all comments to S.P.A.M.
(Address removed, article is from 1989) You are welcome to forward a
copy of your
comments and opinion to AM P/X for possible publication.
Metres: Gateway to AM
The most effective way to preserve AM
on the amateur bands is to attract the interests of more hams. We have
an excellent opportunity to do this now that 10 metres is open during
the high part of the current sunspot cycle. Most HF transceivers on the
market today have the capability of transmitting high quality, true
double sideband AM albeit low power, and many of these rigs have
excellent AM receivers.
Until recently, use of the AM mode on
these transceivers was frustrating for the average uninitiated amateur.
10 was dead, and the 25 to 40 watts output on AM was ineffective on the
crowded 75, 40 and 20 metre phone bands where the big guns hang out.
Linear amplifiers are tricky to tune up on AM, especially for the
technically inexperienced, so the AM position on the mode switches of
most of these transceivers have remained unused. But now that 10 is
open, low power operation is possible with excellent results. Using a
simple but effective antenna such as a dipole or ground plane, the low
power AM signal from a transceiver can work coast to coast and round
the world, with strong, high quality, pleasant-to-listen-to signals,
and the QRM is usually minimal, and bandwidth is not so much a concern.
Let's take advantage of this
excellent opportunity to get more amateurs interested in AM. Talk up 10
mtr. AM at local ham club meetings and hamfests. If you operate 10 m.
SSB, why not invite your contacts to QSY up to 29.0-29.2 and try out
their rigs on AM. It may take some patience to talk some of your
contacts through the procedure of getting their rigs properly adjusted
on AM transmit (the instruction manuals are woefully inadequate in
explaining the principles of AM transmitter adjustment), but the
results will be worthwhile if more hams are bitten by the AM bug. The
relaxed, QRM-free, hi-fi QSO's possible on ten are bound to attract
newcomers to AM, if they can only be persuaded to try it the first
Once the 10 m. AM'ers are hooked,
they can be guided through the lower bands and introduced to higher
power rigs available today, including government surplus, old broadcast
transmitters, vintage equipment, homebrew, and AM linear operation.
While the band is open for the next
few years, let's maintain our highest profile on 10 metres. AM
newcomers can later be guided to the lower frequencies via 160, where
the QRM is also minimal, especially above 1840 khz. With their
fledgling operation on AM a pleasant success, these hams will
eventually gain the experience necessary to tackle the greater
challenge of 75, 40 and 20-metre AM operation. The very survival of AM
on the lower frequency ham bands may depend on whether the AM community
today takes advantage of this golden opportunity!
W1AW Shuns Amateur Radio "Appliances"
An interesting commentary on
"state-of-the-art" amateur transceivers appears in December, 1989 QST.
In a feature article displaying the renovations at W1AW, the reasons
are given why the League chose to equip its bulletin station with
transceivers made by Harris Corporation for commercial service, instead
of the more familiar equipment manufactured for ham use.
Since the station is on the air 10
hours a day, 362 days a year, at a thousand watts out, the transmitters
had to be rated for punishing duty no ham rig will encounter. The
possibility of using regular amateur transceivers and amplifiers was
explored with several manufacturers, but that idea was soon abandoned.
If ham rigs were designed for this kind of service, few amateurs would
be able to afford them.
The number one problem with amateur
radio equipment is what engineers call Mean Time Between Failure. If
you take the cover off any 1980s ham transceiver, you will encounter
another major problem: serviceability. Commercially built ham rigs are
not easy to work on. Individual hams can afford down time but W1AW
cannot. Finally, it is explained, there was concern over the constant
changing of commercially built ham gear. W1AW was looking for many
years of service from this equipment. They could have ended up stuck
with radios no longer in production, and as many hams already know,
repair parts would eventually become difficult to obtain.
In the past, the ARRL's lab engineers
built custom rigs, and it was originally recommended to go the homebrew
route. But it was decided that the lab engineers would be taken away
from their regular duties such as testing equipment for QST product
reviews and building and testing projects for the Handbook. Otherwise,
outside help would have to be hired and construction facilities set up
for a one-time project. The League decided that commercial service gear
was cost competitive when all the intangibles of homebrewing were
- QST, December 1989, pp. 14-17
Accused of Jamming Earthquake Relief Efforts
The following item appeared in the
October 27 issue of Westlink
malicious interference to
HF nets--and the apparent unwillingness of the FCC to solve the
problem--was the single greatest handicap to amateur radio relief
efforts following the devastating 6.9 magnitude earthquake that hit
northern California on October 17, according to Frank Collins, N6TAF,
who runs the Veterans Administration Hospital amateur radio station in
Los Angeles. Collins, who brought the VA station on line immediately
following the quake, says that he cannot believe fellow radio
amateurs----even its lunatic fringe-could possibly act this way in
light of the massive devastation: "We got on 20 meters, and we have a
guy singing on AM-he is in the AM mode-and he is singing 'The Star
Spangled Banner' and 'Glory Glory Hallelujah.' And we have these others
who get on there and tune up their radios and make comments like, 'You
can't help nobody in the disaster area!' Well, why don't they watch a
little television and see some of these kids that are being pulled out
of crushed cars. I mean, even the hope that you give people by trying
to help them is a lot better then saying, 'No, we can't do anything
because we have a jammer on frequency.' This is the lunatic fringe [of
amateur radio] and maybe in the future we ought to have psychiatric
testing to get an amateur radio license!"
The jamming definitely seems
organized. Collins noted that three or four interfering stations would
band together to harass a net that is in operation and then move onto
the next one. And no band seemed to be safe. Collins noted that the
malicious interference seems to follow the flow of disaster
communications: "We had three Veterans Administration hospitals on line
on 14.287 MHz and it was intentionally jammed between the Long Beach VA
and the West Los Angeles VA. And we were also on 40 meters and had a
station come on there and say 'you can't help those people up in San
Francisco, and good riddance, we won't have to worry about the AIDS
epidemic.' That's one of the comments that was made."
Collins said that his people
unable to contact the Cerritos, California FCC office to request
assistance in keeping the QRM clear of net operations: "The number is
busy all of the time." He says that he spoke with the FCC in
Washington, but they were unwilling to act, referring him back to the
Cerritos office which could not be reached.
In view of our efforts to gain support for
the AM cause in the impending AM power issue, this is the kind of
publicity we don't
need. Nothing in the story suggests that the
offenders were regular operators of AM or members of the AM community
as we know it. With widespread availability of AM equipment in the form
of multi-mode transceivers, there are thousands of lids with instant AM
capability. Any one of them could decide to jam emergency traffic with
his appliance in the AM mode. Nevertheless, any news report connecting
AM with such activity is likely to give us a black eye in the mind of
the greater amateur community, and this can be especially damaging in
light of the tenuous position of AM in amateur radio at the present
the AM Press/Exchange:
I was greatly saddened to learn that
W2VJZ was cited by the FCC for "Broadcasting." Up until 1-1/2 years
ago, when I was located on the east coast, I used to work W2VJZ almost
every day. I never considered Irb's actions and comments made to me
during our QSOs a violation of the rule against broadcasting. Of course
his comments were many times critical of the establishment. He was
fighting "City Hall" for many years. This we should try to understand.
Is freedom of speech an illusion? I thought it was guaranteed by the
U.S. Constitution. (So did Irb.)
I also listened to K1MAN playing
broadcaster on 75, (My letter to him objecting to his actions went
unanswered.) I feel sure that Irb's actions were brought on by the
lengthy un-checked useless broadcasts of K1MAN. These were a
considerable thorn in the side of east coast AMers on 75 since they
always began on top of QSO in progress.
Why was not K1MAN not cited by the
FCC for "Broadcasting?"
Byron H. Kretzman, W2JTP/7
Many of us have dedicated hundreds of
hours of our personal time of late in the collecting of petitions,
writing of letters, presentations to League officials, and
presentations to ham clubs in the promoting of the positive side of AM
in the attempt to keep our present power limit- in fact, to even just
keep AM operation legal in the face of strong opposition from many
amateurs. And along comes W2VJZ who by his childish on the air tantrums
designed to deliberately get the goat of the FCC and amateur community
in general has probably undone much of the goodwill generated by our
sweat and financial commitment to the AM cause.
If W2VJZ wishes to exercise his
constitutional rights of free speech in such a manner in the future, I
recommend doing so on SSB rather than on AM. Better yet, I recommend
that he turn in his ham license entirely and continue to operate with a
"handle" as the CB operators do. Hell, since the Constitution
guarantees us free speech and freedom of assembly, no radio license
should even be required in the first place, by golly, and Irb could
really make a
statement by doing so.
Thanks, Irb. I sincerely appreciate
your help. Hopefully you can continue to look like a self centered
idiot as well on SSB after they cut our power back and finally outlaw
AM operation thanks to your confirming the League's and FCC's worst
feelings about AM operators being a bunch of selfish, band hogging
PROMOTION OF AMPLITUDE MODULATION
Jim Taylor W4PNM
There comes a time during the normal
course of human events when we all must evaluate our existence (AM) and
make a determination as to whether or not we want to take a hard stand
for our right to operate AM.
First, my topic of course is the
Preservation of AM for those of us who enjoy the old fashioned mode.
Also, to introduce this old outmoded style of modulation to the
newcomers. Have you noticed the SSB rigs on AM, those signals emitting
from SSB rigs with amplifiers are coming for the most part from SSB
oriented hams who happen to tune across the AM signal, and liked what
Have you ever considered the newer
ham licensed since the 60's has not had any choice but to buy an SSB
rig. My son is a prime example. He just recently got back active on the
air with his Drake Twins, and he finally got around to asking me what
all this talk is he hears about AM. His next statement was, "I don't
know anything about AM, it looks too complicated". I had MY chance to
let him it on the nostalgic kick I have been on for going on 7 years,
now. Believe it or not with his father ( me ) and his grandfather W8DFV
Chick, both old AM operators, he has never been exposed to AM
operation. How you like them apples?
Well, I have given him a few choice
words, and directed him to get on AM if he wants to talk to us! But,
unfortunately it is not that easy when it comes to the other non-AMers.
So, the way I see it we must do something special to attract more
Lets start with setting an example!
Our operation on the band should be beyond question. Our signals should
be the best we know how, and our operating procedures should be the
best also. Let us welcome anyone who sounds like they would enjoy AM.
Let us encourage them to get or help them build a AM high level plate
modulated transmitter. All this is very mindful of the days when some
of us progressive guys promoted SSB with a fever! Starting in 1955
while in the employ of Collins Radio, I was one of many who traveled
around the country promoting SSB. We went to all the radio clubs we
could get to, and talked about the features of SSB. Slowly but surely
we sold the world on that mode. Now, I hate to admit that I played a
very important part of that switch over. On behalf of Collins, I tried
to give a KWS-1 and 75A-4 to W1AW, and they refused! Now, we should be
trying to get W1AW back on AM!
All of us should go to as many
hamfests as possible, in groups and organized if that's possible. We
all I should make a strong effort to promote AM as a high quality mode
of transmission. Some time ago I read Don Chester's remarks regarding
bandwidth usage. The SSBers make no bone about our wide bandwidths, and
chastise us for using too much. If that be the case, as Don says, how
can they defend SSB when CW would take much less than they use. The
answer to this, of course, is our licenses give us the privilege of
operating any mode we wish. Sure, we use more bandwidth, but we sound
much better. I guess that's a trade off to some degree.
Let's take a look at our so-called AM
windows. The most familiar to me is 3885. There are many nights I hear
no AM activity on there at all. When that occurs, the SSB signals move
in, then when we get on we are the culprits. What's the answer to that
dilemma? The way I see it, it is the need for more AM activity in the
AM window. I hasten to mention, that as long as there is activity the
SSBers will stay clear, that steady heterodyne drives them crazy. There
have been many times, while listening I hear SSBers from the south, and
AMers come on up north, and the SSB operators pitch a fit. About that
time I must admit I take advantage of the situation and turn on my rig
and start talking to those big AM signals from the north. When I do
that, you should hear them. I am not talking about a deliberate plot to
QRM, but rather a slightly off frequency maybe a couple Kc away. They
don't like it and often I'm challenged. My standard answer to them is,
I don't own the frequency and they don't either! I advise them they
have chosen to operate in the middle of the AM window, and more AMers
than not are crystal controlled. If they won't operate in the AM Window
I promise not to operate in the SSB part of the band. Most of the guys
will accept my kind dissertation, there are a few that want to dispute
it, but my opinion is, if there was constant activity on there, they
wouldn't have to inclination to get on the frequency in the first place.
For those of you who were not present
at the Atlanta hamfest last year, you missed me running around with my
special shirt that says, AM Kilowatts Forever"! A little corny I
suppose, but very effective! Because a multitude of hams asked me what
it was all about. The AMers who wish they were still on AM came out of
the woodwork and identified themselves. I would like to think I
encouraged some of them to get back on.
The thought in this article is to
promote AM, but do it in a leadership way. Encourage those bored to
death SSBers to get back ( or get on ) a mode where intelligent
conversations can be had. The mode where hams are really hams, and know
something about radio, and are willing to help their fellow ham with a
problem instead of complain. Let's all be hams in the true sense of the
word. Be leaders, and the rest will follow, when they hear those nice
big beautiful signals, and the voices behind the signal have something
Pushbutton Light Switches Wanted
AM P/X readers came to the rescue
when I was looking for the brown glazed ceramic tube sockets and
Sangamo mica condensers. Now, I am asking for your help again for my
personal collection of old radio and electrical devices to be used in a
I am looking for old style push
button 110-volt a.c. light switches, as shown in the illustrations
below. Every day, old buildings are electrically rewired or torn down,
and this sort of old electrical hardware is tossed out. Few antique
collectors or nostalgia buffs seem to be interested in this sort of
thing, so not only are these switches and cover plates unavailable new,
but practically no antique/collectables dealers bother to keep them.
Check your junk pile, and if you have
any of these lying around, in any condition, I am interested in
begging, buying or trading for them. I am also interested in cover
plates, especially solid brass or bakelite. I will gladly pay a
reasonable price plus shipping costs.
Donald Chester, K4KYV
Editor and Publisher, AM P/X
Amplifier Tube Modification for Viking I
by Ronald G. Reu WB0LXV
I recently obtained a Johnson Viking
I transmitter in fairly good condition. And as with all my transmitters
I try to obtain a few extra tubes to serve as spares. As many of you
know, the 4D32, which is used in the Viking I and some Collins
transmitters, is very hard to obtain. Fortunately though, I was able to
obtain the original assembly manual with the transmitter.
I was quite surprised to find in the
back of the manual a description of changes required to use an 829B as
final amplifier. I had never considered the 829B as a substitution for
the 4D32 because the 829B is a dual tetrode where the 4D32 is a single
tetrode. However, the tube tables in my 1949 Handbook lists for
interelectrode capacitances for each section of the 829B to be 1/2 that
of the 4D32. That means when both sections are placed in parallel, the
interelectrode capacitance closely equals that of the 4D32. There are a
few other changes in the description to take into account different
screen voltage requirements and different pin connections. The tube
socket required for the 829B is the same as the 4D32 socket, so that
doesn't have to be changed.
In case you are not familiar with the
829B, the tube was quite common on the surplus markets from just after
WWII up to about 15 years ago. One can still obtain them for very
reasonable prices at flea markets if one shops around. Fair Radio sales
used to have a bunch of them. I don't know if they have any more or
not. The 829B can be tested on the military TV-7A/U tube tester
provided you have proper adaptor that was usually supplied with the
One note of caution in handling the
829B, the glass envelope surrounding the plate pins is extremely
fragile and any attempt to put strain on the plate pins will cause the
envelope to break. I found this out the hard way several years ago when
I was building a transmitter for 10 and 6 metres.
I have enclosed a copy of the
instructions as found in my manual for the conversion. I suppose the
Collins transmitters could be converted in a similar manner.
Of course if you have a supply of
4D32's tubes, conversion would be meaningless to you. I intended this
article for the person whose transmitter is off the air because of a
blown 4D32. I am in the process of converting my rig to use the 829B
and I don't foresee any problems with it. If I have any problems or
suggestions I will send it in to the AM/PX. Good luck.
Changes required for use of 829B
1. Turn coupling capacitor C31 down
towards chassis to keep the plate leads short.
2. Connect another parasitic choke
(L11) to C31 by means of a solder terminal.
3. Connect a plate terminal (Johnson
119-848) to each of the parasitic chokes L11.
4. Leave pins 4 and 5 of socket X7
grounded to the chassis, but remove the ground lead from pin 7.
5. Remove filament wire from pin 7
and connect filament lead to chassis by means of a solder terminal
under a convenient screw.
6. Connect pins 1 and 7 together with
7. Remove the ground lead of the
filament bypass capacitor C40 and re-connect to ground on the socket
mounting screw near pin 1.
8. Remove C28 lead together with the
grey screen grid lead from pin 2 and connect to pin 3.
9. Either change screen dropping
resistor R28 to 12,500 ohms 20 watts, or connect a 3,000 ohm 10 watt
resistor in series with R28.
10. Remove capacitor C25 and choke L6
from pin 6.
11. Connect a jumper of #14 wire
between pins 2 and 6 allowing it to bow upwards 1/2".
12. Re-connect C25 and L6 to the
center of the jumper to provide balanced drive to the grids.
Adjustment: With the final amplifier
loaded to approximately 230 ma., the voltage divider tap should be
adjusted so that screen voltage is approximately 225 volts. This screen
voltage setting should provide about 80 ma. no audio signal cathode
current in the 807 modulators on the "phone" position.
operation using 829B final within ICAS tube ratings.
CW operation with 115 V 60 cycle ac input:
| Phone operation with 115 V 60 cycle ac
|| 28 mc.
|| 28 mc.
| P.A. CATHODE CURRENT
|| 230 ma.
| P.A. CATHODE CURRENT
|| 230 ma.
| SCREEN GRID VOLTAGE
|| 225 volts (loaded)
| SCREEN GRID VOLTAGE *
|| 225 volts (loaded)
| P.A. PLATE VOLTAGE
|| 660 volts (loaded)
| P.A. PLATE VOLTAGE
|| 620 volts (loaded)
| P.A. GRID CURRENT
|| 12 ma.
| P.A. GRID CURRENT
|| 12 ma.
| P.A. GRID BIAS
|| -97 volts
| P.A. BIAS VOLTAGE
|| -97 volts
| POWER OUTPUT
|| 95 watts
| POWER OUTPUT
|| 87 watts
| MODULATOR CATHODE CURRENT
|| 80 ma. (no signal)
| * - 13,000 ohm screen dropping resistor
MEET THE AMers
Do radio listeners want HIGH FIDELITY?
Reprinted from Electronics February, 1934
In all of the talk about improving
the broadcast system, one question remains unanswered, and points to a
very fundamental problem. Do radio
listeners want wide-range tone
transmission and reception?
Transmission engineers believe that
broadcast stations should handle equally well all frequencies out to
7000 or 8000 cycles. Many of them feel a reallocation of broadcast
channels should be made on this basis.
Some receiver engineers claim the
average listener does not want such wide-range transmission. They point
to the fact that tone controls on modern sets are nearly always turned
as far as they will go toward the bass, and away from high notes.
This difference of opinion is of
vital importance. The cost of broadcast-station equipment, cost of
receivers, cost of telephone lines, cost of preparing programs, the
number of stations that can be put into the broadcast spectrum, the
musical appreciation of millions of youths growing up in radio
homes--all these matters are vitally concerned with the proper
settlement of this difference of opinion regarding high-quality
If people do not like notes higher
than 3000-4000 cycles, all the past musical experience is wrong. To
judge by the best of present day "high-quality" receivers there is
little use in transmitting much beyond 3500 cycles. But it is extremely
difficult to believe this to be the fact. Certainly the experience in
sound pictures does not bear this out. Higher fidelity has resulted in
keener appreciation by the lay audience, and no one would go back to
the poor-quality reproduction of the early days.
If people like high notes in the
original music but do not like them from their radio, something must be
wrong with the radio system. If the trouble is static, higher power is
the answer. If the trouble is distortion products originating in
transmitter or receiver and appearing in the higher portions of the
audible range, the answer is clear. If inter-station racket or
over-modulation is the trouble, the solution is evident.
But before going much further in the
discussion of improving the broadcast system, it seems imperative that
a clear-cut answer be found to the questions raised by proposing to
widen the tone range. Do the listeners want the high frequencies that
make for high fidelity?
West Coast AM Report
AM is going well on 75 metres. There
is activity almost every night 9 to 10:30 PM. The center of gravity of
AM activity has moved northwards. More stations showing up in Oregon,
Washington and Northern California. Southern California has kind of
slowed down. N7JW has a Johnson Desk going from Las Vegas, Nevada.
N6UR, Bakersfield, CA, has a KW-1 on. Various Viking Rangers have
appeared up and down the coast. 160-metre AM is almost nil; the band is
not in good shape and amateur activity in any mode is very light. 40
metre AM activity is just Sunday S.P.A.M. sked and weekend nights.
-Fred Huntley W6RNC
information removed; this
issue is from 1989)
WANTED: 833A tube for display. W6RNC
WANTED: Diagram and instructions for
alignment of a "Knight" 10-tube communications receiver. Also wanted a
FOR SALE: T-368 assemblies -
modulator exciter $15. RF exciter deck with 6000 tube $25. 11 Hy 500 MA
choke $15. Large rotary inductor, 14 uH, #8 silver wire, $35. Tube
testers, Heath IT-17 with roll chart and manual, $35; Hickock
"CardMatic", $50. Will horse trade - I need tubes 8008, 304TL. Bill,
WANTED: VFO for Harvey Wells TBS-50
transmitter. Working or non-working. Pat, WB9GKZ
WANTED: UTC audio transformers LS-18
and LS-49. K4KYV
FOR SALE: Both excellent, DX-100
$100, National NC-184D receiver $100. You pick up. I can't see dials.
W2TGK, Ralph Heerkens
FOR SALE: Viking Ranger, good
condition, works, with manual $120. Bill Drager, K3UMV
WANTED: Stancor ST-203A 10 meter
mobile xmtr. Rich Smith, KF6EA
FOR SALE: 810 tubes (6 ea.), look
like new, but probably used. $60 plus shipping. 4-400A broadcast
pullouts, full output, 3 ea. $100 plus shipping. John Basilotto, KC2EH
WANTED: UTC S-62 filament
transformer. James T. Schliestett, W4IMQ
FOR SALE: Viking II with VFO
excellent $150. Viking II fair $75. WRL Globe linear $100. WRL
Globemaster SR. $100. PE103 Dynamotor $35. Small prop pitch $100.
WANTED: Schematics on BC110 and REL #
206 early transmitters. Parker, W1YG
WANTED: Collins 75A1 receiver in good
working condition and good appearance with manual. WX4C, Don Landes
FOR SALE: Dow Coaxial relays 110
volts, $20 each. Variacs 115 volt @ 15 amps $45 each. Two 19" rack
enclosures black $40 each. Tubes, 807 $3 ea. 1625 $2 ea. Inquire on
is the AM PRESS - An amateur radio publication dedicated to
is the AM EXCHANGE - Offering FREE ADVERTISING to enhance the
availability of AM equipment and parts.
Subscriptions $10 per year (12
issues) in North America. Classified ads (AM related) free of
charge to subscribers and nonsubscribers. Display advertising and
foreign subscription rates on request.
Edited and published by Donald
NOTICE: The purpose of this
publication is the advancement of Amplitude Modulation in the Amateur
Radio Service, and there is no pecuniary interest. Therefore,
permission is hereby expressed for the use of material contained herein
without permission of the publisher, with the exception of specifically
copyrighted articles, provided that The AM Press/Exchange is properly