mikey@techsup (12/30/85)
The folowing is the text of a letter sent to the FCC. It has been
assigned an RM number, I just don't have it now. I'm posting this
to see what kinds of comments are generated, personally, I'm
slightly favorable to the proposition, but time and arguements
will tell. Responses can be sent to me at trsvax!techsup!bbimg!mikey
or to Mr. Stoner, who was the author of the article.
Any mail sent to me will just be forwarded to Mr. Stoner at his
Compuserve address.
Just for info, the responses on HAMNET of Compuserve have been
very positive, the only concerns seriously addressed as of this
posting have been about 6 meters and model airplane people.
Anyway, the text follows
mikey N1DVJ
trsvax!techsup!bbimg!mikey
-------------------------- tear here ----------------------------
Before the FEDERAL COMMUNICATIONS COMMISSION Washington, D.C. 20554
In the matter of
)
)
Creation of a new radio class
)
and allocation of spectrum for
)
the owners of personal computers
)
)
TO: The members of the Commission)
PROPOSAL FOR THE CREATION OF THE PUBLIC DIGITAL RADIO SERVICE
FILED BY
Donald L. Stoner, W6TNS
October 20 1985
SUMMARY OF PETITION
This petition is to identify the need for a new class of radio service.
This radio service is described in the petition as the PUBLIC DIGITAL
RADIO SERVICE.
The petition shows that creation of the service and the allocation of
spectrum is in the public interest, convenience and necessity.
Presently, computer-to-computer communication by the general public is
confined to the telephone network. Millions of computer owners find
that it is increasingly expensive to utilize this network to satisfy
their communication needs.
Establishment of the PUBLIC DIGITAL RADIO SERVICE would permit the
owners of personal computers to communicate by radio. Instead of a
traditional channelized scheme, the petition describes a radio Local
Area Network (LAN). The PUBLIC DIGITAL RADIO SERVICE permits an
infinite number of local area radio networks to be interconnected into
a national packet radio network.
The PUBLIC DIGITAL RADIO SERVICE would allow computer owners to
exchange messages, bulletins, computer programs and other information
by radio, and at no cost.
The petition describes how the Commission could create the PUBLIC
DIGITAL RADIO SERVICE, which will adequately serve the needs of the
public for at least the remainder of this century.
BACKGROUND OF PETITIONER
I have been a radio amateur (W6TNS) since 1954. A large part of my
career has been devoted to the field of writing. For an extended
period, I was the Novice and Technician editor of CQ Magazine. I have
written hundreds of articles and authored several books on the subject
of amateur radio and computer communications. I was also responsible
for the idea which grew to become the OSCAR satellite, and I was able
to make useful contributions to the program during its early stages. I have been an educator and taught at Chaffey College in Southern
California.
This experience provided an opportunity to observe and study personal
motivation, goals, effort versus reward, and so on. During the 70's I
was involved in the manufacturing of Citizens Band communictaions
equipment. Thus, I was able to write about CB initially and then
participate in its "self destruction". The experience afforded the
opportunity to see what "went wrong" and, with hindsight, to realize
how to avoid these mistakes in the future.
In 1983, I made a reply comment to PR Docket No. 83-28. This was the
controversial "No-Code" document. As part of my reply, I proposed "THE
CREATION OF A COMPUTER HOBBYIST LICENSE CLASS".
It was (and is) my contention that this license class would have
brought in literally millions people into amateur radio. However, the
amateur fraternity decided that no amateur radio licenses should be
granted, under any circumstances without a Morse code examination.
Clearly, the proposal for a "computer radio band" received considerable
attention on the part of the Commission. In its decision relative to
Docket 83-28, the Commission left open the possibility of a radio
service for computer hobbyists. However, radio spectrum was not
allocated for such a service.
It is the purpose of this document to further amplify the need for such
a service, to make a recommendation on spectrum allocation, and to
outline technical specifications which will ensure the successful
introduction and usage of the PUBLIC DIGITAL RADIO SERVICE.
The accumulated knowledge of the writer has provided certain insights,
many of which have contributed to the preparation of this document. A
careful and serious consideration of my petition by the Commission is
sincerely appreciated
THE PETITION
Why Is A Computer Radio Band Needed? The increasing popularity of
personal computing is well known. There are presently more than 18
million of these devices in the hands of the public. Today, a computer
can be purchased for less than $100. Thus any American, rich or poor,
can afford to own a personal computer. Many experts feel there will be
a ten-fold increase in the acquisition of computers by the end of this
decade.
The Commission is aware of the popularity of computers. High frequency
digital circuits produce radio and television interference. The
Commission recognized the growth in the personal computer market and
regulated interference levels before an untenable situation occurred.
The Commission is also aware of the popularity of computer
communications via the telephone network. As a result of the
"Carterphone Decision", there has been an enormous increase in type
acceptance applications for telephone modem devices. According to
Creative Strategies International, a Cupertino Calif., research firm,
the modem market will reach $555 million by the end of 1985 and is
expected to top $1.5 billion by 1988. The bulk of these telephone
modem sales are to the owners of personal computers. It is presently
possible to purchase an FCC approved modem for as little as $29.95. If
one assumes an average price of $100.00, there will be 15 million
modems in use by the end of this decade.
Why do owners of personal computers utilize modems? The desire to
communicate with others having like interests does not diminish with
the acquisition of a computer. Computer owners like to play
interactive games, exchange messages and software, assist others having
like computers, and so on. This desire to communicate has provided the
basis for a number of national information utilities such as The
Source, CompuServe, PlayNet, Delphi and The Shuttle. These
organizations allow computer owners to interconnect and exchange all
manner of information via the national telephone network. These
services are extremely popular. CompuServe, for example, claims to
have 250,000 members.
The exchange of information between computer owners is not free,
however. These information utilities charge hourly fees varying
between $3.00 and $20.00, depending on time of access and the data
rate.
More relevant to this discussion is the cost for the transport medium,
the telephone network. In the previous decade, the cost of a computer
was relatively high while telephone costs were relatively low. In this
decade the situation has reversed. Telephone companies are begining to
implement charges based on time and distance for local calls. Thus the
cost to the public for computer communications will increase
significantly.
Recently, a number of telephone companies attempted to impose a
surchage on those using modems. Some modem users have added an
expensive second telephone line. Without this alternate path, the
telephone is essentially out-of-service while the user is on-line with
the computer. Thus the user is unable to receive emergency calls. At
the slow data rates prevalent on telephone networks, these periods can
be quite lengthy.
It should be stressed that much of the existing and future computer
communications could be handled by suitable radio devices. Recently
there has been a significant increase in the interest and use of radio
waves to transport computer data. The trade press regularly mentions
companies trying various approaches which avoid the use of telephone
lines for data communications. The most common activity seems to be
the use of FM subcarriers for point-to- multipoint networks.
Motorola has been a leader in the area of point-to-point data
communications. They offer a wireless data system which allows
portable-computer owners (possessing Motorola cellular-radio
telephones) to transmit data at speeds up to 1200 baud.
Motorola has also supplied a hand-held terminal for IBM field
engineers. It allows two-way communication with a central tranmitter
and computer.
Finally, Motorola has recently petitioned the Commission to share
satellite frequencies in the 1.7 gHz. range to create local area
business radio networks.
All of the above products benefit the business community. They are
designed to make businesses more profitable, productive and/or
efficient by transmitting computer data via radio.
None of the products described above are intended to benefit the
general public. The PUBLIC DIGITAL RADIO SERVICE can make personal
computers more useful, interesting and/or productive to the general
public. It is in the public interest, convenience and necessity that
the public also have access to this precious resource called the radio
spectrum.
While modem communications will continue to be popular, an alternate
cost-free communication path should be available to the computer
public.
This document describes such a service, called the PUBLIC DIGITAL RADIO
SERVICE. It petitions the Commission to create such a service with
suitable regulations and to allocate sufficient spectrum to insure the
success of the service.
TYPE OF SERVICE PROPOSED
In the past, there has been some discussion of permitting computer
communications on the Citizens Band. CB usage and channel loading is
currently a fraction of what it was during the previous decade. Four
additional CB frequencies, formerly used for the remote control of
objects, are virtually unused. Other bands (in particular, 49 and 72
mHz) could accomodate computer communications.
In the above examples, a channel scheme is implied. The use of
communnication channels, however, leads to ham type operations ("send
the data to me on channel X"). Channelized operation and shared
services would probably not work for the PUBLIC DIGITAL RADIO SERVICE.
The users of this service will expect operation and performance similar
to that of a telephone modem. Telephone modems do not have channels.
The computer public is not interested in the radio aspects of
communication other than as a means to an end. Thus there is no need
or desire for voice communications as part of an equivalent radio
modem. This precludes the "chit-chat" type of operation which was
destructive on the Citizens Band.
Sharing frequencies with voice communication (such as on CB) would be
unacceptable. Interference, caused by frequency sharing, would garble
the received data. Since the interference is transparent, the typical
user will assume that data errors are caused by equipment faults.
Thus, it is essential that the frequency allocation for the PUBLIC
DIGITAL RADIO SERVICE not be shared with any other service.
Channelized plans inevitably lead to a further problem. If the service
becomes popular, there will ultimately be a need for more channels.
This is exactly the situation which occurred on the Citizens Band. The
Commission is well aware of the problems which resulted from the
disruption of adding additional CB channels.
The alternative to a channelized scheme is to send the data at high
rates using packet technology. A single wideband channel can be
thought of as a digital highway with addressed packets entering and
leaving the route in a highly organized manner (see "What Is A Packet
Radio Network?").
AN ALLOCATION OF SPECTRUM FOR
THE PUBLIC DIGITAL RADIO SERVICE
A wideband digital channel can only be accomodated within the VHF band
or higher frequencies. To keep the cost of equipment low, a band
between 30 and 300 mHz is ideal. Some readers may feel that a service
as described should be placed in the UHF or SHF range. This might be
true if a suitable allocation within the 30-300 mHz band did not exist.
However, within this frequency range there is a band, 2 mHz in width,
which is virtually unoccuplied and therefore unused. I refer to the
spectrum between 52 and 54 mHz. Radio amateurs are permitted to
operate on frequencies between 50 and 54 mHz (the six meter band). For
a number of reasons, this band is "underoccupied".
It is estimated that out of 400,000 radio amateurs in the United
States, less than 1,000 are active on the six meter band.
Due to the potential for inteference with adjacent television channel 2
(54-60 mHz), virtually all six meter users operate between 50 and 52
mHz. For all practical purposes the radio spectrum between 52 and 54
mHz is wasted.
The radio spectrum is a precious natural resource much the same as our
beaches and national parks. The public access to the radio spectrum
resource is severely limited. The entry fee is an amateur radio
license. This can be justified in instances where the resource is
severely limited or where national security is involved. It cannot be
justified by any stretch of the imagination when the beach or park is
totally deserted!
POTENTIAL FOR TV INTERFERENCE
The Cause of Interference- Radio amateurs have not used the 52.0- 54.0
mHz portion of the six meter band due to the high risk of television
interference. This interference problem occurs through no fault of the
amateur or the transmitting equipment.
A typical ham six meter transmitter can induce several volts of radio
frequency energy in a nearby television antenna. The induced voltage
can be thousands of times stronger than the television station being
received. Thus, the strong signal from the ham station can overload
the TV receiver.
This effect is called crossmodulation and can cause interference on all
channels. The level of interference can vary in intensity from
"crosshatching" to a total loss of the picture.
Radio amateurs have access to many bands of frequencies throughout the
radio spectrum. None of the other bands share the close proximity to
television channels as does the six meter band. Clearly, amateurs have
resolved the problem of television interference simply by not using
this portion of the six meter band.
To date, no one has addressed the problem of using these frequencies in
a manner which will not cause television interference.
This portion of the spectrum could be utilized by reducing the power
output of the transmitter below the point where television interference
can occur.
Eliminating Interference- It is the opinion and experience of the
writer that no televison interference can occur from a radio modem
operating in the 52.0- 54.0 mHz band if the following conditions are
met:
1. The signal strength of the TV station being received exceeds 100
uvolts.
2. The effective radiated power of an adjacent radio modem does not
exceed one watt.
3. The separation between the radio modem antenna and the television
antenna exceeds 8 meters.
4. The radio modem antenna is vertically polarized with respect to the
horizontally polarized TV receiving antenna.
5. All modulation and spurious products which fall outside the
authorized bandwidth conform to the FCC 43 plus 10 log10 rule.
If these conditions are met, the 52.0- 54.0 mHz band will be suitable
for the PUBLIC DIGITAL RADIO SERVICE and no significant television
interference will occur.
WHAT IS A PACKET RADIO NETWORK?
The reader may be familar with the term "local area network" (LAN). In
this system a limited number of computers are connected together by
cable in a manner which permits intercommunication. A packet radio
network is an infinite number of LAN's connected together by radio
waves.
A packet radio network may be thought of as a digital equivalent of the
U.S. Postal Service. The information to be sent to another computer
is equivalent to a letter. The letter is placed in an envelope which
includes a destination address. This is called the packet. This
packet is sent along with those of other users into the network, which
acts like a mailbag.
The packet address also includes something like a postal zip code. The
postal analogy varies somewhat in the handling of messages. Each radio
modem connected to the network is a destination mailbox. At the same
time it can also act as a "post office" for others connected to the
network.
Each user is considered to be a "node" in the PUBLIC DIGITAL RADIO
SERVICE. These stations or nodes constantly monitor the transmissions
(mailbags), looking for packets (envelopes) which are addressed to
them. If a message addressed to the node is detected, it is held in
memory (the recipients mailbox).
The message may be intended for a nearby node as indicated by the "zip
code". In this case, the node "mailbox" does not activate. Rather,
the node becomes a "post office" and passes the message to one or more
other nodes. The reply from the destination computer is handled in the
same manner but the direction is reversed.
Packet radio transmission (movement of the "mailbags") can occur at
very high speed. In fact, the speed is only limited by the bandwidth
of frequencies alloted to the network. This petition requests a band
of frequencies 2 mHz in width. This is sufficent to handle data rates
in excess of 1 million bits per second. When one considers that the
typical rate of data transmission on a telephone network is 300 bits
per second, it can be seen that the PUBLIC DIGITAL RADIO SERVICE can
handle a large number of simultaneous users.
Unlimited Users- Actually, the number of simultaneous users is
unlimited due to an advantage of FM radio transmission called the
"capture effect". Each node will "hear" (or capture) only the
strongest stations in the immediate area of the node. More distant
stations will be inaudible and will not cause interference. Thus users
in two adjacent cities (for example) can communicate within the cities
without interference from users in the adjacent city. Of course, if it
is desired to send a message to a user in the adacent city, the
appropriate nodes will repeat the message until it reaches the
destination and triggers a delivery acknowledgement. Other messages,
not addressed to the adjacent city, will be ignored.
WHAT IS A RADIO MODEM?
The device to control the node (see previous section) functions similar
to a ham radio "digipeater" but at a much higher speed. Since the the
term "digipeater" has no significance to the general public, the node
controller is refered to as a "radio modem".
What is it?- Technically speaking, the radio modem is a non-persistent,
carrier sense, multiple access with collision avoidance device. In
practice, the radio modem consists of a small box, whip antenna and
coaxial cable. The unit contains a receiver and transmitter, in
addition to an RS-232 computer interface.
In addition to acting as a transceiving device, the radio modem is also
capable of repeating received packets on the basis of a stored
algorithm. In other words, it will receive, store and retransmit
messages along the addressees route. Note that it is capable of acting
as a repeater even if it is not connected to a computing device.
Training- Upon activation, the radio modem executes a stored training
sequence. When first installed, the radio announces its presence and
digital address in the network. The radio modem transmits its position
with respect to other units, determines the digital address of other
nearby units and finally, adjusts its power output to the minimum
required to maintain communications with the other nearby units. This
power can vary from 1 milliwatt for densely populated areas to the 1
watt maxiumum in rural areas. It is essential that the radio modem
transmit only sufficient energy to maintain contact with other nearby
radio modems (nodes).
Training the radio modem for power output insures that a minimum signal
level is radiated by the antenna. The purpose is to minimize the
possiblilty of television interference. Some readers may point out
that one watt is simply not enough power for rural areas. However, it
is not the purpose of the PUBLIC DIGITAL RADIO NETWORK to duplicate the
elaborate trunks of the public telephone network. There are bound to
be areas which cannot pass messages. Under no circumstances should
consideration be given to increased power output in these instances.
If a high power mode is available, it will be abused.
A COMPARISON WITH CB RADIO
Those reviewing this petition may have a tendency to make comparisons
with the introduction, usage and the degeneration of the 27 mHz
Citizens Radio band.
The following points are presented with this comparison in mind. No
one, including the petitioner, would like to see the PUBLIC DIGITAL
RADIO SERVICE meet the same fate as the 27 mHz Citizens Band.
There is a major reason for the chaos which developed on the 27 mHz
Citizens Band. The licensees of this service did not feel it was in
their interests to abide by the Rules and Regulations. We can learn
from this experience by designing a service where Rule compliance is
in the interests of the user.
MODULATION- There must be no provision for voice communications in the
PUBLIC DIGITAL RADIO SERVICE. Users of radio modems wish to exchange
digital data, not the spoken word.
IDENTIFICATION- Enactment of a PUBLIC DIGITAL RADIO SERVICE will not
affect the licensing workload of the Commission. Services which are
essentially self-regulating (such as the remote control of objects,
garage door openers, etc.) do not require the use of call letters.
Inherent in the addressability of the radio modem, is a built-in aid to
compliance and enforcement. Each radio modem has its own unique
identification code, that is, its packet address. This is both the
serial number and digital address of the unit. This code also
identifies the manufacturer and the physical location of the radio
modem. Violations of technical requirements can be easily be
correlated by manufacturer. In other words, if a significant number of
units are observed to be defective, the manufacturer can be immediately
determined by serial number correlation.
If a unit is found to be non-complying, a message can be addressed to
that radio modem advising the user of the problem. The Commission
personnel sending the message receives the customary delivery
acknowledgement of the message. Thus there can be no question that the
user received the Notice of Violation.
POWER OUTPUT- A major contributing factor to the "CB problem" was the
addition of power amplifiers to CB radios in an effort to increase the
talk range.
Adding a power amplifier to a radio modem will produce no increase in
performance. The unit will "retrain" to reduce its power output to
maintain the nominal signal level at nearby radio modems. Thus, the
power delivered to the antenna might be 50 milliwatts (as an example),
with or without the power amplifier.
ANTENNA- To further increase transmitting range, high gain, directional
antennas were connected to CB radios. If the same type of antenna were
connected to a radio modem, it would result in a "negative
improvement". There would be no increase in range, since the radio
modem would retrain to produce the nominal signal strength at nearby
nodes. More important, the radio modem connected to a directive
antenna could miss messages arriving from directions other than the
antenna principal gain lobe. By the same token, raising the elevation
of the antenna would cause no noticable increase in communication
range.
OFF FREQUENCY OPERATION- Illegal out-of-band operation caused sizable
headaches for the Commission enforcement personel. This will never be
the case with the PUBLIC DIGITAL RADIO SYSTEM however. There is only
one "channel" or band. If, by some means, the frequency of a radio
modem were lowered, the data would be destroyed by amateur radio
transmissions. If it were raised, video information from TV channel 2
would do the same thing.
TECHNICAL SPECIFICATIONS
The "radio modem" (node controller) to be used in the PUBLIC DIGITAL
RADIO SERVICE shall meet the following specifications:
FREQUENCY BAND- Equipment authorized to operate in the PUBLIC DIGITAL
RADIO SERVICE shall be capable of receiving and transmitting data
within the band from 52.0 to 53.999 mHz.
MODULATION- The data shall frequency modulate the carrier in a
frequency shift keyed scheme. Under no circumstances will equipment
authorized for use in the PUBLIC DIGITAL RADIO SERVICE have provision
for voice modulation or detection.
MODULATION AND SPURIOUS PRODUCTS-
The data rate (see Note 1), waveform and signal processing shall be
such that all products which fall outside the authorized bandwidth be
suppressed by 43 plus 10 log10 (mean output power, in watts) decibels.
POWER OUTPUT- The power delivered by the final amplifier stage into a
72 ohm load shall not exceed 1.0 watts. Further, the radio modem (node
controller) shall have an initial powerup "training" mode. Upon
powerup, the power output will be 1 milliwatt.
The power will increase during "training" in 3 db. steps until contact
is established with nearby radio modems (node controllers). This value
is stored in memory and becomes the nominal power output for the radio
modem.
ANTENNA- The antenna shall consist of a vertical radiator which does
not exceed one-quarter wavelength. The antenna shall exhibit no gain
or directional characteristics. The antenna shall be supplied with a
nominal length of coaxial cable.
TRANSMITTER IDENTIFICATION- Each radio modem shall have an imbedded
identification which is transmitted as part of its packet address. The
address will be used to identify the manufacturer, the serial number
and the routing code of the equipment.
PACKET CONSTRUCTION- The packet and destination address will be
contained in the header. The header will be constructed to limit the
number of destination addresses. This is done to specifically preclude
the transmission of "junk mail".
REMUNERATION- Users of the PUBLIC DIGITAL RADIO SERVICE shall be
specifically prohibited from receiving any form of remuneration or
compensation, either in the form of funds, goods or services, for
handling data on the PUBLIC DIGITAL RADIO SERVICE (see Note 2).
TYPE ACCEPTANCE- Type acceptance procedures, similar to those for
Citizens Band equipment, will be required. This insures that
commercially manufactured equipment used in the PUBLIC DIGITAL RADIO
SERVICE meets the specified technical requirements for this service.
NOTE 1- No data rate is given in these proposed specifications. It
should be left to industry to determine the data rate. Schemes,
unknown to the writer or Commission, may permit higher rates within the
authorized bandwidth than conventional theory would dictate.
NOTE 2- The purpose of this provision is to prevent the use of the
PUBLIC DIGITAL RADIO SERVICE for the benefit of common carriers. The
restriction should not be construed to preclude the use of the PUBLIC
DIGITAL RADIO SERVICE for business applications. For example, the
radio modem would be extremely useful within buildings to avoid the
need for local area network cabling. It is likely the signals of an
office radio LAN would not connect to the external PUBLIC DIGITAL RADIO
SERVICE.
The reader might envision that the service would be usurped by the
business community. This is not likely, however, due to the
self-regulating nature of the PUBLIC DIGITAL RADIO SERVICE. Businesses
are used to the near instantaneous response of telephone data
communications.
In comparison, the message response of a packet radio network is
relatively slow. Only small businesses would find these delays
tolerable. These are the same business which can least afford the
increase in telephone rates.
There is an analogy in the use of the Citizens Band. Numerous channels
are available and the equipment is quite inexpensive. Even so, this
band is seldom used for business purposes. There are simply too many
disadvantages for the business community.
CONCLUSION
In response to this petition, the Commission may point out that there
has been no popular "groundswell" to create a computer radio service.
Likewise, there was no public interest in the creation of a television
service in the 30's. However, in 1932, the Commission recognized the
significance of television and allocated two bands for development of
this new technology.
By the same token, the Commission recognized the impact that FM radio
broadcasting would have on sound reproduction. In 1941 they allocated
an eight mHz band to bring high fidelity sounds to the public.
In either case, there was very little awareness that such technologies
were possible when the allocations were made.
The creation of a PUBLIC DIGITAL RADIO SERVICE is another instance
where the Commission could take the initiative and create a new service
in keeping with current technology.
International Regulations- Since the allocation is above 50 mHz, it
appears that no international treaties would be involved in making the
proposed allocation. Rather, it is likely that other countries would
develop a similar service for their citizens.
Amateur Radio Opposition- It is safe to assume there will be sizable
opposition to this petition by amateurs. The writer has been a radio
amateur for 30 years. During this period, no permanant allocation has
been "taken away" from the amateur radio fraternity.
However, there can be no defense by amateurs of the inactivity on 6
meters. A reallocation of the frequencies requested would benefit the
majority at virtually no expense to the minority.
Amateur Radio Colaboration- The principal purpose of this petition is
to obtain an allocation for a public computer communication band. The
writer would not object if this goal could be achieved as part of the
Radio Amateur Service. The computer public would accept an
administrative fee in return for access to the radio spectrum.
However, they would never accept any sort of "testing" to achieve this
goal.
The writer would like to thank the Commission for the opportunity to
submit this petition. Further, the writer appreciates the
consideration this petition will receive by the members of the
Commission.
Signed 20 October, 1985
----------------------
Donald L. Stoner, W6TNS
6014 E. Mercer Way
Mercer Island, Wa. 98040
(206) 232-6968karn@petrus.UUCP (Phil R. Karn) (01/04/86)
What follows are my initial reactions to the Stoner proposal for creation of a Public Digital Radio Service. Since I do not have access to Compuserve, I'd appreciate it if somebody forwarded this note to Don Stoner. I agree that the time has come for such a service. As involved as I am in the development of amateur packet radio, I can see plenty of legitimate applications for low cost, personal digital radio communications that properly lie outside the scope of the Amateur Service (e.g., business use, need for encryption, etc). Further, the need for such a service is enhanced by the amateur community's continuing opposition to any form of "no code" license, an irrational attitude that will surely prevent packet radio from ever reaching its full potential in the Amateur Service. Having said this, however, I must take issue with the details of Stoner's proposal, in particular his frequency and bandwidth recommendations. As a radio amateur, I instinctively resist the "giving away" of any amateur allocation, even one as lightly used as 52-54 Mhz. I am also not convinced by Stoner's contention that an inexpensive radio modem, particularly one with an emission bandwidth of 2 megahertz, could be operated without interference to nearby TV receivers tuned to Channel 2. At the very least, I would like to see the results of any tests he has conducted to reach this conclusion. Another problem I forsee with such a large allocation, which apparently would be used for a single, wideband RF channel, is multipath dispersion. The DARPA packet radio community has found that packet radios operating in a typical urban or suburban environment are effectively limited to data rates of 100 to 400 kilobaud because of the intersymbol interference caused by multipath propagation effects. Only when a strong line-of-sight signal component fully captures the receiver is it possible to operate at higher speeds. Therefore, it is clearly not necessary to allocate such a wide portion of spectrum if the intent is only to provide a single RF channel. I think that Mr. Stoner's proposal would be an excellent one once he finds another, smaller, piece of spectrum outside the amateur bands to use. Phil Karn, KA9Q
mikey@techsup (01/09/86)
I posted the original of Mr. Stoners letter to usenet, and I'll forward all respones to him. All comments are appreciated, both pro and con. For the record, I've gotten information that the ARRL will oppose this proposal. Finally, I'll reread the original and other documents that I didn't post to usenet and any that are relevent, I will post here. I didn't post them all before, but I see a need now as there seems to be the feeling here that we are 'giving up' a section of the spectrum when the feeling from the other documents is that this will not be a surrender, just that there would be an additional service, as it would require a license to operate but that would be allowed under technician and higher class license. In other words, this would be a new 'no code' license for 'digital' use only. I personally think it is a great vehicle for enticing new blood into the HAM ranks, as newcomers will get a taste of the RF spectrum and then want to move up to VHF high or UHF once they get their TECH license, or into HF if they learn more than the minimum code. mikey N1DVJ trsvax!techsup!bbimg!mikey
stephany.WBST@XEROX.COM (01/16/86)
Objections to Mr. Stoners proposal: (1) The fundamental communication link in this world is cable, not radio. (read any engineering handbook on communication). There is far too little spectrum space for the communication of the world. radio only comes in when (1) mobile units are involved which cannot be connected by radio, and (2) remote areas where it is impracticle for a cable. This is the present thinking and the proposal of spectrum for units that can be connected by cable would be a waste of spectrum. Tradition grants BC and TV spectrum on the basis of historical use, which could be replaced by cable, but this cannot occur with present thinking. Since the proposal is only as a convenience and cost reduction for computer people it would hardly justify spectrum space, not being a necessity. There are dozens of people that want spectrum space as a convenience and dont get it because it is not a necessity. (2) The Canadian digital brought in about 200 people. Since the population of the U.S. is about 10 times that of Canada, then the estimated number would be 2000. This is not sufficinet to justify a new licese class. Experience has shown that what keeps out people is the technical test, not code, particularly in young people. You propose the oppocite, no code yet technical knowledge. (3) The proposal licenses a mode that is already licenses. If we allow digital licenses, then why not CW only or phone only, or TTY only? It makes little logical sence. I am not saying you may not have merits to your proposal, I am saying the above arguments against your proposal must have good answers. If you can't come up with some, then your out. Good luck. Joe N2XS