Homebrew repeater controllers
ph...@ux1.cso.uiuc.edu
> I'm interested to know if anyone has built a repeater controller based
> upon an IBM PC or clone. I'm willing to dedicate the entire PC with
> harddisk to the repeater controller operation.
It seems like a lot of money to me to tie up in a controller.
> I would expect that the controller would offer all the features of
> the ACC line plus things like:
Well, these things are about as expensive (and in my opinion, not worth
it due to lack of the features I want).
> Has anyone built the necessary interface hardware? I'd be more likely
> to program such a thing if I didn't have to build the hardware.
It would be nice to have all the functionality of a controller for a
repeater on a single board you can plug into a PC. I had asked about
the interface between controllers and the actual repeaters some while
back here on rec.ham-radio, and the general concensus I got was that
there is not standard interface bewteen the repeater hardware and the
controller. I don't know what assumptions, or excess hardware for all
the variations, controllers like the ACC ones have.
I would consider the following connections to be essential:
Controller ---> Repeater
1. On/Off (PTT) the transmitter.
2. On/Off the audio.
3. On/Off the transmit CTCSS.
4. Audio from CPU for ID, battery mode indicator, etc.
Repeater ---> Controller
1. Carrier level
2. Discriminator noise level
3. Discriminator output
4. Audio
Other ---> Controller
1. Battery voltage
2. Battery current
3. PA voltage
4. PA current
5. SWR
6. Tower lights current
7. Clock/Time
Whether or not things like CTCSS decoder/encoder, DTMF decoder/encoder,
squelch level, etc., should be in the "radio" or on the controller are
probably religious issues. I personally want CPU control over these things
so I can do everything from setting them remotely to programming them to
dynamically change to meet conditions. For instance, I would want different
squelch levels in effect for "idle" and "ready" states (idle is when the
repeater has not been transmitting lately; ready is between transmissions of
an active QSO) so that it requires a good signal to bring up the machine, but
it will tolerate some fading during the QSO. Likewise a different set of
squelch levels would be required if CTCSS is present (to allow locals to
access w/o CTCSS, but DX needs CTCSS). Another possibility is to allow
users to turn off the need for CTCSS on a per-QSO basis (it comes back on
when the machine goes to idle state). Perhaps CTCSS could be required to
bring up the machine, and not needed once it is up. I could put all these
things in a huge matrix and plug in LOTS of values to program the machine
with, and I know that ACC controllers cannot do this.
Cross-band and multi-band repeaters need even more sophisticated control,
especially when multiple receivers are concurrently receiving different but
good signals; what do you want your repeater to do?
I, too, prefer to program the software (and I mean writing machine/assembly
code, not CONFIGURING as you would do to an ACC even though they CALL that
"programming") instead of building the hardware. However, building a
controller from a PC compatible mother board, or perhaps (depending on just
how easily boards can be added) Kantronics new DataEngine, seems like a
reasonable way to get the hardware in place ready for programming. Having
a hard disk is not essential, but does give you some flexibility. You could,
if you are careful, upload new controller code via radio.
--Phil Howard, KA9WGN-- | Individual CHOICE is fundamental to a free society
<ph...@ux1.cso.uiuc.edu> | no matter what the particular issue is all about.
Perry Scott
If the controller spends most of it's time in an air-conditioned shack, it
should be fine. :-)
Perry Scott
Jeff DePolo
IMHO, using a PC as a repeater controller is a good idea, and shouldn't be
difficult to implement. PC's are nice because most of the hard work that
would normally have to be done in hardware in a non-CPU based repeater
can be done in software. Access codes can be easily changed, PROMS
don't have to be burned for different CW ID's, the ID's themselves can
be generated by the computer, etc. The way I see it, the above caveat
can easily be remedied by not using floppy drives/a hard drive in normal
operation. The system should be set up so that upon booting, both the
control software and all data necessary to run the repeater, including
the custom control codes, ID's, messages, etc. should all be loaded into
memory to prevent unnecessary use of the disk drive and also to increase
speed. But that's probably pretty obvious. I can't think of any real
reason why the computer would have to write anything to disk as the
repeater is used. What's there to be logged that easily be converted
to a digital format that's of any use?
BTW, most of the interfacing can probably be done without having to directly
communicate with the computer byte-wise. Control lines on the RS232 port
make handy binary lines. Having the computer set lines high is a quick
and efficient way of flipping relays, keying CW, etc. They can be used
as input as well - have a receiver set the line high when a signal
opens squelch. It's a lot easier than having to read and write 8 bits
on the data lines and allows for more than one device to be connected
to the computer unlike 2-device serial communications. And if one
port isn't enough, another serial port can be added for about $25.
A stripped-down single-floppy XT clone with 2 serial ports should cost
less than $500 new, probably under $300 used. If money is really
tight, use as C64 (ick) or trash-80.
About the only "real" communications that would be necessary would be
getting DTMF tones from the receiver to the computer. That shouldn't be
all that difficult either. Less than 5 chips in actuality. Take
a DTMF decoder and a UART and you're 99% done. Things like detecting
S/N for voting or detecting PL might be a bit more difficult, but they would
be necessary in a non-computer-based repeater anyway. Control of the
repeater would be simple - just tack on a modem.
If you do decide to go through with the project, keep us posted. I'd
be interested in hearing how you went about the whole project. I'm
sure it's been done many other times before, but it would still
be interesting.
--- Jeff
+-----------------------+-----------------------------------------------------+
| Jeff DePolo N3HBZ/AA | Internet: dep...@eniac.seas.upenn.edu |
| Univ. of Pennsylvania | RF: 146.685- 224.40- 442.70+ 144.455s (Philadelpia) |
| Computer Science Eng. | Twisted pair: (215) 386-7199 home |
| Class of 1991 | Carrier pigeon: 420 South 42nd St. Philly, PA 19104 |
+-----------------------+-----------------------------------------------------+
co-op
>About the only "real" communications that would be necessary would be
>getting DTMF tones from the receiver to the computer.
Radio shack has informed me that they have discontinued the SSI2102 touch
tone decoder IC from the retail line. They could not tell me whether
or not the part would be available on order.
It may be worthwhile for all hams to comb the local radio shack's now, as
any that are still left in stock will probably be half price ($5-6 range).
Unfortunately, these chips are not easy to come by ... DTMF decoders
are not listed by Digikey, JDR Microdevices, Jameco, or any of the
other "standby's". The alternative - building DTMF decoders out of
eight (seven if you don't care about ABCD tones) 567's - is messy and
a pain in the neck to align properly.
73's Chris WZ2B
--
Christopher E. Piggott, WZ2B (ex-N2JGW)
Computer Consoles, Inc. (an STC company) Rochester, NY
cs.rochester.edu!cci632!ccird7!cep or uunet!ccicpg!cci632!ccird7!cep
Jeff DePolo
>
>Radio shack has informed me that they have discontinued the SSI2102 touch
>tone decoder IC from the retail line. They could not tell me whether
>or not the part would be available on order.
Since the chip is made by SSI, I'd imagine that some of the better distributors
that carry SSI components would still have them. If not, there are lot
of companies that make DTMF decoders for the sole purpose of repeater
control. They can't be all that expensive. With the expanding use of
DTMF for controlling devices like phone answering machines or even
BSR remote control power switches, they should still be pretty easy to
find. I have a couple of the SSI chips from Radio Shack and for $7.77,
which is what I paid, you can't beat the deal. If you can still find
them, grab a few. They are definately worth it.
Gary Coffman
>
>> I'm interested to know if anyone has built a repeater controller based
>> upon an IBM PC or clone. I'm willing to dedicate the entire PC with
>> harddisk to the repeater controller operation.
>
>It seems like a lot of money to me to tie up in a controller.
A group of local amateurs led by N4CLA has developed a controller based
on a plugin board for the PC. It digitizes the receiver output, processes
it, and converts it back to analog for the transmitter. It is roughly
a DSP system with shared dual ported memory that allows voice mail,
a dynamic voice detection type squelch, touchtone detection and generation,
and over 200 commands. It will work in any PC, even the original IBM
PC1, and it can be used without the PC if you don't need voice mail.
They have installed it on two repeaters so far and plan to introduce
it commercially at the upcoming Atlanta Hamfest. It is a very flexible
system with very high quality audio.
I am of the school that says "two wires make a light" and don't feel
the need to have such a powerful controller. However for those who
feel the need, this thing is a technical marvel.
Gary KE4ZV
Gary Coffman
Some real world experience. We have been using PCs for packet switches
on mountain tops for over two years. Hard disk drives have been the
MOST reliable part of our installations. Of course we are using old
5 to 10 megabyte clunkers that have broad tracks and loose tolerances,
but we have had absolutely zero failures in unconditioned radio huts.
What does fail is the floppy drive. The diskette disintigrates in
summer with the oxide peeling off and plating onto the heads. In
winter the diskette gets so brittle that it fails. So don't leave
a diskette at the site if you want it to survive.
Gary KE4ZV
Ed Wells
# In article <26...@netnews.upenn.edu> dep...@eniac.seas.upenn.edu.UUCP (Jeff DePolo) writes:
#
# Radio shack has informed me that they have discontinued the SSI2102 touch
# tone decoder IC from the retail line. They could not tell me whether
# or not the part would be available on order.
#
# It may be worthwhile for all hams to comb the local radio shack's now, as
# any that are still left in stock will probably be half price ($5-6 range).
#
# Unfortunately, these chips are not easy to come by ... DTMF decoders
...
What is so hard about getting DTMF chips? Try to call Motorola,
Signetics, National Semiconductor or others and ask them for the part
number to handle what you need. Then ask them for their local
distributor for the area.
...
# --
# Christopher E. Piggott, WZ2B (ex-N2JGW)
# Computer Consoles, Inc. (an STC company) Rochester, NY
# cs.rochester.edu!cci632!ccird7!cep or uunet!ccicpg!cci632!ccird7!cep
--
=========================================================================
Edward E. Wells Jr., N3IAS, President Voice: (215)-943-6061
Wells Computer Systems Corp., Box 343, Levittown, Pa. 19058
{dsinc,francis,hotps,houxl,lgnp1,mdi386,pebco}!wells!edw
Jon Bloom
> Some real world experience. We have been using PCs for packet switches
> on mountain tops for over two years. Hard disk drives have been the
> MOST reliable part of our installations. Of course we are using old
> 5 to 10 megabyte clunkers that have broad tracks and loose tolerances,
> but we have had absolutely zero failures in unconditioned radio huts.
> What does fail is the floppy drive. The diskette disintigrates in
> summer with the oxide peeling off and plating onto the heads. In
> winter the diskette gets so brittle that it fails. So don't leave
> a diskette at the site if you want it to survive.
Interesting. I've had a packet switch on a mountain top here for about a
year and the floppy hasn't experienced any problems. (One difference is
that I'm using disk drives with head load--the head isn't in contact
with the disk unless it's being used.) On the other hand, it only
accesses the disk to boot up, which it hasn't had to do for about six
months. Hmmm... maybe I had better check the disk that's in there!
--
Jon Bloom, KE3Z | American Radio Relay League
Internet: jbl...@uhasun.hartford.edu |
Snail: 225 Main St., Newington, CT 06111 | "I have no opinions."
Alan Bloom
Nobody has mentioned any potential problems with RFI. My XT causes
significant interference to my 2M rig. Seems like there would be a
potential problem placing an unshielded PC on a mountaintop in a vault
filled with dozens of repeaters at different frequencies.
Al N1AL
Jon Bloom
Oddly enough, this is the one problem I expected to see that I _didn't_
see in setting up the packet switch here. (The packet switch is probably
a worst-case problem; it has 3 computers: the PC and 2 TNCs.) Considering
that the equipment is in a _wooden_ enclosure, so there's practically
nothing between the equipment and the antenna, electrically speaking, and
considering that the antenna is only about 30 feet away, I was amazed.
Perhaps it's because a ground-plane antenna has very little response in
the down direction? I don't think it's anything to do with the particular
antenna, since I have a 2-meter antenna and a 220 antenna of different
designs and neither one hears the computer. Maybe I'm just incredibly
lucky. (Although other experiences on the mountain make me doubt that!)
Jon T. Adams
Actually, Al, there are. That's why site owners throw hams off the hill
first. Well, maybe not always first, but in the back of their minds, it's
not a bad idea...
PC on hilltops need to be in fairly well-shielded cases, complete with
feedthroughs and such, and preferably no outward indication that it's a
pc.
'Course, on our local hilltop, the biggest problem is the guy who runs
three GMRS radios, with no isolators on the transmitters; the transmitters
also put out broadband hash that flames our own receiver on 440.
But, heck, for the few more years that it'll be in existence, ham radio's a
great hobby...
- 73 -
jon nw6h
--
Jon Trent Adams, NW6H |"As nightfall does not come at once, neither
J...@hydra.jpl.nasa.gov | does oppression... It is in such twilight that
"jpl don't know me from squat"| we all must be most aware of change in the air-
however slight- lest we become unwitting victims of the darkness." W.O. Douglas
Gary Coffman
There is a potential for real problems here. What we do is use standard
shielding techniques (that the manufacturers should have already done)
to solve this problem.
Here is roughly how to do it.
1. Choose a multilayer motherboard. The inherent shielding
of having ground and power planes in the motherboard is
your first line of defense.
2. Scrape ALL the paint off all mating surfaces of the case.
Add screws every three to four inches to every mating
surface.
3. Add copper tape or copper screening to all openings in the
case.
4. Ground the case to the radio ground using low inductance
copper strap.
5. Use shielded cables to and from the PC.
This should be all you need to do to quiet the noisest PC. Of course
if you are going to leave a monitor and keyboard at the site, then
you have to treat them too. I strongly recomend that you do not leave
a monitor or keyboard at the site as doing so invites theft.
A well engineered RF site will use good quality hardline for ALL RF
cabling including duplexer cabling. Thus RFI from controllers will
have to enter through the antenna which is way up the tower out of
the near field of the controllers. Of course those of you who maintain
repeaters know that most commercial installations are so sloppy that
they would embarrass the average ham.
Gary KE4ZV
Jeff DePolo
>In article <125...@hpnmdla.HP.COM> al...@hpnmdla.HP.COM (Alan Bloom) writes:
>>Re using PC's as repeater controllers:
>>
>>Nobody has mentioned any potential problems with RFI. My XT causes
>>significant interference to my 2M rig. Seems like there would be a
>>potential problem placing an unshielded PC on a mountaintop in a vault
>>filled with dozens of repeaters at different frequencies.
>>
>>Al N1AL
>
>There is a potential for real problems here. What we do is use standard
>shielding techniques (that the manufacturers should have already done)
>to solve this problem.
>
Some of the cheaper import PC's don't even have FCC approval, so the chances
of getting a dirty computer are pretty high these days.
Cheap PC's are probably some of the worst polluters, espescially non-metal
incased computers such as C64's. But along the lines of IBM PC-clones,
they are typically noisy, but RFI leaking through cables or in other
ways getting into the actual radios isn't as much of a problem as it
may seem. Far field interference down the feedline through the antenna is
highly unlikely, considering most repeaters have some sort of bp/br filters
in addition to helical resonators on the front end of the receiver itself. A
good repeater setup should have RG-214 or similar double-shielded coax
connecting the receiver, transmitter, duplexers, filters, preamps, etc. inside
the shack. Even the noisiest PC would have a hard time getting into this
type of coax. At least I've never seen it happen. Take into consideration
that most people have no problem using their PC and TNC with a 2m rig,
even with the radio and computer sitting right next to each other, typically
neither being particularly well shielded.
The only possible source of interference would be near-field RFI caused
by poorly shielded radios located extremely close to the computer itself.
Monitors and hard or floppy disk accesses seem to create the most RFI. But
once the repeater is up, disk accesses should be nil and it's easy enough to
shut off a monitor. Harmonics generated by square and sawtooth waves from
inside the PC should be pretty well attenuated by the PC's cabinet itself,
no to mention the radios' cabinets. I frequently use an HT in PC labs
filled with 20+ PC's and also in a machine room filled with VAXes,
Harris machines, DEC and Apollo workstations, etc. and rarely have anything
break squelch, even on a wide-open hot-front ended HT. How bad can it really
be? Admittedly, I've never use a PC in a repeater installation, but use
one all the time on packet and never have problems. Even with the 2m rig
sitting on top of the computer and using a 1/4h mag mount next to it on
a filing cabinet.
ph...@ux1.cso.uiuc.edu
> Further, a random kerchunk is no longer illegal, since hams are now only
> required to ID at the termination of a series of transmissions. For
> someone trying to find a hot spot to get into the machine with his
> handheld, a series of kerchunks preparatory to IDing is neither illegal
^^^^^^ ^^ ^^^^^^^^^
> nor improper.
^^^ ^^^^^^^^
It is ANNOYING! Why do you need more that one? Why do you even need to
kerchunk at all? Just transmit, state your purpose, ID, and let up.
If you don't normally hear a tail on this repeater, kerchunking isn't
going to get you anything anyway, so just listen for someone to answer.
If you do normally hear a tail (either a BEEP or just a noise burst) then
you know you got in. If not, you might not have, or was seriously choppy.
If it is a test in and of itself, it is a complete transmission and needs
and ID at the end of it, that means when the testing is done, ID it. Since
a series of kerchunks give you no more information that ONE does, you only
need one, and you need to ID at the end of it.
Mike Shirley
>In article <1990Jun26.1...@msuinfo.cl.msu.edu> ed...@jafus.mi.org (Eddy J. Gurney) writes:
>>Knowing what the 850 is
>>capable of, it's one HECKUVA controller, and I can understand why when I talked
>>to them in Dayton, they didn't worry too much about "other repeater control-
>>lers." :-) Seriously, though, there isn't much the 850 can't do.
>
>Except sound like a repeater. Every single machine I've ever heard that
>had one of these things in it sounded like a pinball machine. I'll bet
>the ham who designed it drives a 1959 Buick with 400 pounds of chrome
>tailfins and a push-button automatic transmission.
>
Our repeater group has an 850 running here in Sandy Eggo. While the pinball
machine may be descriptive on occation, it is not necessarily the norm.
When you have up to four link/remote bases online, it's very easy to get lost
as to which reciever(s) are active and which transmitters are enabled
(especially in cross-band operation). The 850 allows no courtesy tones or
voice to id the carrier/PL closures. I prefer the tones, low level, low freq
and of short duration. I think that a few seconds of hang-time go hand in
hand with the voice-delay/kerchunk eliminator lash-up (on 220 anyway due to
lack of Commercial surplus equipment). I don't like bursts of white noise,
twice on each conversation turn-around on a simple Ker-Chunk repeater. And
with the junky (aka SLOW PL decoders) on 220 radios, I think the voice delay
is a SLIC way around the problem.
But the 850 is not without some bummer bugs, of which ACC, won't acknowledge,
fix, or even tell you of. But that's another story (a long story). Basicly,
to each his own. If you have one repeater on a clear (more or less, mostly
less here in SoCal) let's have hang-time and telemetry. Zero hang-time for
multiple repeater/remote base combinations with duplicate coverage.
**************************************************************************
Mike Shirley, WB6WUI INET: mi...@pnet03.cts.com
PO Box 460 ARPA: crash!pnet03!mi...@nosc.mil
Lakeside, CA 92040-0460 UUCP: {hplabs!hp-sdd nosc}!crash!pnet03!mikey
**************************************************************************
Jay you ignorant splut! Maynard
>> Further, a random kerchunk is no longer illegal, since hams are now only
>> required to ID at the termination of a series of transmissions. For
>> someone trying to find a hot spot to get into the machine with his
>> handheld, a series of kerchunks preparatory to IDing is neither illegal
> ^^^^^^ ^^ ^^^^^^^^^
>> nor improper.
> ^^^ ^^^^^^^^
>It is ANNOYING! Why do you need more that one? Why do you even need to
>kerchunk at all? Just transmit, state your purpose, ID, and let up.
OK, let's try it from my bedroom with a low-powered handheld, into my
favorite repeater:
"K5ZC monitoring."
If I haven't found a hot spot yet, all a listener will hear is:
"hisssstorsssss".
Really useful. I probably won't get a response, and have learned
absolutely nothing.
>If you don't normally hear a tail on this repeater, kerchunking isn't
>going to get you anything anyway, so just listen for someone to answer.
How do I know whether it's worth it to move a few inches and try again?
>If you do normally hear a tail (either a BEEP or just a noise burst) then
>you know you got in. If not, you might not have, or was seriously choppy.
...exactly why I feel a hang timer is mandatory.
>If it is a test in and of itself, it is a complete transmission and needs
>and ID at the end of it, that means when the testing is done, ID it. Since
>a series of kerchunks give you no more information that ONE does, you only
>need one, and you need to ID at the end of it.
Ah, but a series sometimes DOES provide more information, especially
with the "handheld on the fringe" scenario: you can find out where the
hot spot is. (No, it's not always where the receiver S-meter peaks, and
not all radios have S-meters.) The objective is to determine when you're
likely to get into the repeater; when you find that out, I agree that an
ID is necessary.
--
Jay Maynard, EMT-P, K5ZC, PP-ASEL | Never ascribe to malice that which can
j...@splut.conmicro.com (eieio)| adequately be explained by stupidity.
"It's a hardware bug!" "It's a +----------------------------------------
software bug!" "It's two...two...two bugs in one!" - _Engineer's Rap_
Brian Kantor
a) they own radios they trust never to break
b) they use a repeater they trust never to break
c) you kill them
d) the repeater drops off the air so fast they can't hear the kerchunk
Which do YOU think is the most achievable?
(Recall that if you have a real radio, IT won't make any noise when the
signal comes and goes either, so if the repeater also lacks pinball machine
noises, it could be kerchunked all day long and nobody'd care.)
- Brian
John Moore
]>If it is a test in and of itself, it is a complete transmission and needs
]>and ID at the end of it, that means when the testing is done, ID it. Since
]>a series of kerchunks give you no more information that ONE does, you only
]>need one, and you need to ID at the end of it.
]
]Ah, but a series sometimes DOES provide more information, especially
]with the "handheld on the fringe" scenario: you can find out where the
]hot spot is. (No, it's not always where the receiver S-meter peaks, and
]not all radios have S-meters.) The objective is to determine when you're
]likely to get into the repeater; when you find that out, I agree that an
]ID is necessary.
Actually, there is a problem with this. When you are hunting for hot spots,
you are listening on the receive frequency. But... you need a hot spot for
the transmit frequency also. Since hot spots are usually caused by
multipath, the transmit and receive hot spots are often not in the
same place. Most repeaters don't give you any indication of how strong
your ker-chunk is. Micor's, I notice, do give you some hint - the
squelch tail is slightly longer on a weak signal.
--
John Moore HAM:NJ7E/CAP:T-Bird 381 {ames!ncar!noao!asuvax,mcdphx}!anasaz!john
USnail: 7525 Clearwater Pkwy, Scottsdale,AZ 85253 anasaz!jo...@asuvax.eas.asu.edu
Voice: (602) 951-9326 FAX:602-861-7642 Advice: Long palladium, Short Petroleum
Opinion: Support ALL of the bill of rights, INCLUDING the 2nd amendment!
John Boteler
> In article <3050...@ux1.cso.uiuc.edu> ph...@ux1.cso.uiuc.edu writes:
>>[I wrote:]
>>> Further, a random kerchunk is no longer illegal, since hams are now only
>
> favorite repeater:
Yes, but none of this has anything to do with 'homebrew repeater controllers'.
I'd like to hear more about phil's intelligent 'carrier level' sensing
system which decides how strong a signal is and takes appropriate
action, whether that is keying a repeater, preventing it from being
keyed, or whatever have you.
Phil?
--
John Boteler {uunet | ka3ovk}!media!csense!bote
NCN NudesLine: 703-241-BARE -- VOICE only, Touch-Tone (TM) accessible
Gary Coffman
>In article <3050...@ux1.cso.uiuc.edu> ph...@ux1.cso.uiuc.edu writes:
>>[I wrote:]
>>> Further, a random kerchunk is no longer illegal, since hams are now only
>>> required to ID at the termination of a series of transmissions. For
>>> someone trying to find a hot spot to get into the machine with his
>>> handheld, a series of kerchunks preparatory to IDing is neither illegal
>> ^^^^^^ ^^ ^^^^^^^^^
>>> nor improper.
>> ^^^ ^^^^^^^^
>>It is ANNOYING! Why do you need more that one? Why do you even need to
>>kerchunk at all? Just transmit, state your purpose, ID, and let up.
>
>
>Ah, but a series sometimes DOES provide more information, especially
>with the "handheld on the fringe" scenario: you can find out where the
>hot spot is. (No, it's not always where the receiver S-meter peaks, and
>not all radios have S-meters.) The objective is to determine when you're
>likely to get into the repeater; when you find that out, I agree that an
>ID is necessary.
>
my handie scratchie", but repeated and continuing unmodulated kerchunking
followed by BLEEP-BLOOP all day long wears the nerves of monitoring stations
VERY thin. It seems that nearly every operator MUST do this EVERY time
he turns on his radio. You can stand up at club meetings and ASK that
they don't do this, but still it continues day in and day out. The
ONLY thing that seems to stop this kerchunking is to take away the feedback
by going to no squelch tale.
Gary KE4ZV
Gary Coffman
>People stop kerchunking the repeater when
> a) they own radios they trust never to break
> b) they use a repeater they trust never to break
> c) you kill them
> d) the repeater drops off the air so fast they can't hear the kerchunk
>
>Which do YOU think is the most achievable?
c? :-)
>
>(Recall that if you have a real radio, IT won't make any noise when the
>signal comes and goes either, so if the repeater also lacks pinball machine
>noises, it could be kerchunked all day long and nobody'd care.)
> - Brian
Gary KE4ZV
Jeff DePolo
a transmit carrier hang time is to have the repeater only key up when a carrier
breaks squelch, PL is heard (if applicable) AND audio is present. This forces
the would-be kerchunker to say something, hopefully his call sign. At least
one repeater I know of here uses this technique, quite successfully. The
reason it works is that nobody wants to key down and say "Hello" or "Testing",
without IDing for fear that his voice would be recognized.
After the repeater is first brought up, the audio-presence test should probably
be ignored, as there is a good chance that the first few ms of a transmission
may get cut off before the controller realizes that audio is present, but the
delay would probably be insignificant if done properly.
The only problem with this system is that unfamiliar users would probably
assume that the repeater was down. But hey, if everybody did it this
way, kerchunkers would soon become extinct. Yeah, right :-)
Jay you ignorant splut! Maynard
> a) they own radios they trust never to break
> b) they use a repeater they trust never to break
> c) you kill them
> d) the repeater drops off the air so fast they can't hear the kerchunk
>Which do YOU think is the most achievable?
D, obviously. Repeaters and user radios may not break, but they will
NEVER make the repeater 100% of the time. The problem with D is that the
users go away, too, since the repeater is unusable.
>(Recall that if you have a real radio, IT won't make any noise when the
>signal comes and goes either, so if the repeater also lacks pinball machine
>noises, it could be kerchunked all day long and nobody'd care.)
Obviously, your definition of "real radio" only includes anything with a
MICOR squelch circuit. By that definition, only Motorola makes "real
radios", and not all of them; my IC32AT definitely doesn't qualify, but
my custom-built Flitefone III full-duplex mobile does, since I built a
MICOR squelch for it. Of course, it's easy to tell with a full-duplex
radio whether or not you're making the repeater, but the only in-band
full-duplex portable radio I've seen is the (surprise!) Motorola APCOR
cardiac telemetry radio - at well over $1K on the used market, and it's
a luggable.
co-op
>
>I'd like to hear more about phil's intelligent 'carrier level' sensing
>system which decides how strong a signal is and takes appropriate
>action, whether that is keying a repeater, preventing it from being
>keyed, or whatever have you.
This sort of stuff is really neat. Here in Rochester we have a repeater
that uses (I believe) a General Electric voting selector. The unit uses
an internal noise source to compute the signal-to-noise ratio of the in-
coming signal, and takes that one. This signal may not necessarily be
the one with the highest S-reading (or so I am told). The selector also
employs circuitry to provide a switchover "threshhold", i.e. receiver 1
will stay in effect until receiver 2 is markedly improved, so that if you
are smack in the middle of the two it won't clack back-and-forth.
The part that amazes me is that it is a completely analog device. (Yes,
I am stuck in the digital world, and I would have guessed DSP only).
Does anybody have any (technical) insight on how these things work?
--
Christopher E. Piggott, WZ2B (ex-N2JGW)
Computer Consoles, Inc. (an STC company) Rochester, NY
cs.rochester.edu!cci632!ccird7!cep or uunet!ccicpg!cci632!ccird7!cep
ph...@ux1.cso.uiuc.edu
> I'd like to hear more about phil's intelligent 'carrier level' sensing
> system which decides how strong a signal is and takes appropriate
> action, whether that is keying a repeater, preventing it from being
> keyed, or whatever have you.
>
I have a number of ideas, none of which I have ever experimented with
yet. I really would have to get into the experimenting to really come
up with anything useful (or determine if I am off base). But until I
can experiment in software without having to build my own hardware
(since I don't want to experiment with that right now) the ideas will
just have to sit in limbo. We'll see what can be done with the
Kantronics DataEngine once they get their promised developer's
technical reference manual out. I just hope they have not hired one of
George "read my lips; no new taxes" Bush's relatives to publish it.
ph...@ux1.cso.uiuc.edu
A voting system would basically be relatively simple to do. Sure you could
do it in software, and I personally would rather do so since my software
writing experience is a few orders of magnitude greater than my hardware
building experience. But a hardware based one would not be that hard to
do either. You could do it by having a binary tree where the leaves are
hardware representing the input signals. Each node selects the quieter
of the two signals and at the end pops out the quietest signal. Rather
than have a noise filter and detector pair at each node, only one per
input is really needed, and its output, a constant DC level, would be
passed on from node to node.
Gary Coffman
>In article <14...@ucsd.Edu> br...@ucsd.Edu (Brian Kantor) writes:
>>People stop kerchunking the repeater when
>> a) they own radios they trust never to break
>> b) they use a repeater they trust never to break
>> c) you kill them
>> d) the repeater drops off the air so fast they can't hear the kerchunk
>>Which do YOU think is the most achievable?
>
>D, obviously. Repeaters and user radios may not break, but they will
>NEVER make the repeater 100% of the time. The problem with D is that the
>users go away, too, since the repeater is unusable.
>radios", and not all of them; my IC32AT definitely doesn't qualify, but
Now we get down to it. The users that go away are the ones with handie-
scratchies trying to use them from marginal locations on the fringes of
the repeater's coverage. In my opinion, if you are not equipped to put
a full quieting signal into the repeater you shouldn't be attempting to
use the repeater except in that mythical life or death situation where
no other means of communications are available. And even in that situation,
if someone is not there to hear your distress call, all the little beeps
in the world won't help you. The only thing worse than listening to
endless beeps and boops is listening to someone sitting in his easy
chair fading in and out of the repeater with each breath because he
is to lazy to walk over to his base station and put a solid signal
into the machine.
Gary KE4ZV
Brian Kantor
encoding the received signal strength (or s/n ratio) at the receiver
site and carrying that under the signal on the link to the voting site.
Some use various PL tones and divide the signal strength into two or
three levels - strong, moderate, weak - and send an appropriate tone.
Others use a series of audio tones around 2500 Hz or so, and notch them
out of the system at the voter.
Still others transmit the strength separately on another channel - most
commonly done when there are several clusters connected by microwave,
like the City of San Diego does.
This isn't that hard for a ham to build. I can do the PL flavour with
just two chips at the receiver: A set of simple comparators (like the
4-in-a-can LM339) watch the signal strength, each set to a laddered
level, and go to a priority encoder (like an LS148), with the output
from the encoder driving the bottom bits of a simple PL encoder like
the SS-32. Voila, you are now encoding the signal strength on the link.
At the voter site, you need a bunch of PL decoders (n per receiver),
and you have a uP that samples all of them and decides which to
select for feeding the transmitter. The nice thing about the uP is that
the circuitry for it will be simpler than doing it with discrete logic,
and you can do such things as add hysteresis to avoid chattering between
receiver sites.
Disadvantages: it's an A-1 prime pain in the ass to get the audio to
sound good and consistent across all those links; and the PL decoders
are slow to respond so that the voting system won't act like a diversity
setup - it's incapable of following mobile chop, for example.
The person who makes and sells these for the ham market gets to deal
with any patent issues.
- Brian
Jay you ignorant splut! Maynard
...or because all his available funds are tied up elsewhere, like a real
Unix computer to put on the packet network.
Face it, Gary...not all hams are rich enough to put money into
high-powered radios for every car and base stations for every band. Some
of us have other things to do for the advancement of the art.
Robert Casey
>a transmit carrier hang time is to have the repeater only key up when a carrier
>breaks squelch, PL is heard (if applicable) AND audio is present. This forces
>the would-be kerchunker to say something, hopefully his call sign. At least
>one repeater I know of here uses this technique, quite successfully. The
>reason it works is that nobody wants to key down and say "Hello" or "Testing",
>without IDing for fear that his voice would be recognized.
This would work until someone figures out that one could press a touch tone
key on his touch tone pad on his HT or mic to make some audio. Or blow some
air into the mic, to make some noise. A dedicated kerchunker will find a way
to kerchunk. But you should ID.
73 de Whiskey Alpha Two India Sierra Echo
(why am I using phonetics on the UUCP net? :-)
Gary Coffman
>
[lots of stuff deleted]
>
>...or because all his available funds are tied up elsewhere, like a real
>Unix computer to put on the packet network.
>
>Face it, Gary...not all hams are rich enough to put money into
>high-powered radios for every car and base stations for every band. Some
>of us have other things to do for the advancement of the art.
>
on a local repeater. Most of these problems seem to be related to using
a HT with rubber duck in areas where they just don't work well.
I agree that not all hams are rich, Lord knows I'm not, but surely any
ham worthy of the name can build a simple quarter wave ground plane
antenna and permanantly fix it in a good spot at his home. And any
ham should be able to install an outside antenna on his car and use
it instead of the terribly inefficent rubber duck INSIDE the car.
There seems to be a mentallity in ham radio today that goes "The
manufacturer put a duck on my radio and I don't dare change it."
If you have to rock back and forth in your easy chair to find the
"hot spot" you need a better antenna and/or more power to properly
work THAT repeater.
Gary KE4ZV
Rusty Carruth
>.... Most repeaters don't give you any indication of how strong
>your ker-chunk is....
Well, there was a repeater down in Tempe (AZ), located on a grain elevator,
which supposedly could give you a signal report if you 'asked it' to.
A friend of mine knew the owner of the repeater and knew all the codes to
send to get it to do all sorts of things. Unfortunately, there was something
wrong with it when he tried to give me a demo. (or he forgot the codes! :-)
John, do you know of which repeater I speak? I'm sorry I don't even remember
the freq it was on, its been a while (but I think 144 or 145).
(I don't suppose you could count such a contact during a contest?)
(On second thought, forget I even asked the question!) :-) :-)
Rusty "Possibly short for this (usenet) world" :-) and :-( N7IKQ