Is using RTTY over FM frowned upon?

Status
Not open for further replies.

kylehotchkiss

Member
Joined
Dec 28, 2011
Messages
7
Location
Virginia
I have developed an Arduino RTTY modulator. It generates the sounds, which would go into my handheld FM radio. I would be doing this in the experimental section of the 2m band, broadcasting my callsign, etc. I just wasn't sure if this would be allowed or frowned upon since the RTTY is still going being modulated as FM?

Thanks!
 
Joined
Dec 26, 2004
Messages
1,217
Location
Tulsa
Back in the 70's RTTY on 2M FM was very common, we had a local group that built a TU (terminal unit) and interfaced it with a 2 Meter radio, we used real Teletype machines and most with auto start. The national simplex RTTY channel was 146.70, Wasn't uncommon doe someone to turn on their machine which started everyon's machine and then ring the bell several times then shut down, this was funnet at 2 am in the morning. This was before packet came along. Nothing replaced the clickty clack and the smell of Teletype oil from a model 28 machine
 

zz0468

QRT
Joined
Feb 6, 2007
Messages
6,029
It's not frowned upon at all. Just find the frequency where the local activity is so when you transmit, people will actually have a chance to hear (demodulte) you.
 

LtDoc

Member
Joined
Dec 4, 2006
Messages
2,145
Location
Oklahoma
The only part of the whole thing that I'd worry about is finding an unused frequency. That depends on just how 'congested' the band is in your particular area, which may/may not be a problem at all. That would be the same for any band.
- 'Doc
 

ecps92

Member
Joined
Jul 8, 2002
Messages
10,659
Location
Taxachusetts
Ahhh the ole ASR28's [The No.28 Automatic Send - Receive Teletypewriter]

Still have manuals at my Desk :cool:

Back in the 70's RTTY on 2M FM was very common, we had a local group that built a TU (terminal unit) and interfaced it with a 2 Meter radio, we used real Teletype machines and most with auto start. The national simplex RTTY channel was 146.70, Wasn't uncommon doe someone to turn on their machine which started everyon's machine and then ring the bell several times then shut down, this was funnet at 2 am in the morning. This was before packet came along. Nothing replaced the clickty clack and the smell of Teletype oil from a model 28 machine
 

mtindor

OH/WV DB Admin
Database Admin
Joined
Dec 5, 2006
Messages
7,528
Location
Carroll Co OH / EN90LN
The only part of the whole thing that I'd worry about is finding an unused frequency. That depends on just how 'congested' the band is in your particular area, which may/may not be a problem at all. That would be the same for any band.
- 'Doc
Finding an unused frequency? "Is this frequency in use?" a couple times on FM voice might do the trick. A few "QRL QRL? de xx#xx" on RTTY might do the trick.

My guess is that as long as you aren't on a typical simplex freq (146.52, 146.535, 146.55, 146.565, 146.58), on a repeater input/output, on 144.39, or on the typical packet freqs, you aren't going to run into frequencies that are in use. Plenty of spectrum left to run RTTY on.

Hell, in most areas you won't even hear packet anymore.

Mike
 

kylehotchkiss

Member
Joined
Dec 28, 2011
Messages
7
Location
Virginia
Phew, that's a relief. I am actually just getting my own computer to demodulate it. It was just the quickest way I could think of sending back measurements from something. (I know APRS is more suitable, but making a microcontroller do that from scratch is rather hard)
 

kb2vxa

Completely Banned for the Greater Good
Banned
Joined
Mar 22, 2005
Messages
6,126
Location
Point Pleasant Beach, N.J.
I don't understand what you're trying to do here, RTTY isn't FM, it's FSK. The modern sound card method generates two tones, mark and space, that when fed into an SSB transmitter produce two corresponding sidebands. The end result is the same as shifting carrier frequency, FSK.

I might suggest putting modes in their appropriate sub-bands or you'll get a lot of hams rather upset with you. RTTY being digital you'll find its place in the band plan.
 

Nap

Member
Joined
Sep 10, 2011
Messages
142
Location
Ontario
"I don't understand what you're trying to do here, RTTY isn't FM, it's FSK"

Actually you can look at RTTY as being just audio and you can send it over AM, FM, SSB and even spread spectrum.

What the OP is doing is perfectly valid. The problem is that the ARRL band plan doesn't explicitly have anything referring to "digital modes over FM". There is such provision in the RAC bandplan.

So I'd just place it in "145.50-145.80 Miscellaneous and experimental modes" to avoid discussions with bozos.

Nap.
 
Last edited:

kylehotchkiss

Member
Joined
Dec 28, 2011
Messages
7
Location
Virginia
"I don't understand what you're trying to do here, RTTY isn't FM, it's FSK"

Actually you can look at RTTY as being just audio and you can send it over AM, FM, SSB and even spread spectrum.

What the OP is doing is perfectly valid. The problem is that the ARRL band plan that doesn't explicitly have anything referring to "digital modes over FM". There is such provision in the RAC bandplan.

So I'd just place it in "145.50-145.80 Miscellaneous and experimental modes" to avoid discussions with bozos.

Nap.
That's exactly what I did. Put the handheld at .5w and I think that's a pretty safe place to experiment. Thanks for the advice guys!
 

Nap

Member
Joined
Sep 10, 2011
Messages
142
Location
Ontario
"Is using RTTY over FM frowned upon?"

Depends on whom you ask.

Personally I don't see anything wrong with it as long as you find a proper frequency in the bandplan. And I would actually answer such call and find it fun.

Nap
 

burner50

The Third Variable
Moderator
Joined
Dec 24, 2004
Messages
2,096
Location
NC Iowa
I have developed an Arduino RTTY modulator. It generates the sounds, which would go into my handheld FM radio. I would be doing this in the experimental section of the 2m band, broadcasting my callsign, etc. I just wasn't sure if this would be allowed or frowned upon since the RTTY is still going being modulated as FM?

Thanks!
I have no idea what the "Gentlemens agreements" allow, but my first thought would be "Who Cares" if it is frowned upon.

Amateur radio was created by people experimenting. Experimentation has been the single largest driving factor in amateur radio in the past.


Nobody owns amateur radio, and as long as you're not using it for illegal purposes or encrypting your broadcast, Find a vacant frequency, park your radio there, and HAVE FUN. Anyone who would "Frown upon" the practice needs to get a life.

I was once driving with a friend in another vehicle, and we were "Hiding" around 432MHz, and somebody heard it somehow. Later, I received a nasty E-Mail because that part of the band isn't supposed to be used for voice traffic. I could care less what the ARRL's idea of a band plan is as there is no law that requires that it be followed.

As long as you're not interfering with existing traffic on a frequency, do whatever, wherever you want.
 
Last edited:

K9WG

Member
Joined
Nov 12, 2010
Messages
1,364
Location
Greenfield, Indiana USA
I always wondered why. According to the comparison here:

Mode Comparison

there's no advantage to PSK31 other than using less bandwidth.
My thoughts exactly. It seemed back in the late 1990s to early 2000s that PSK31 was the "preferred" ECOM digital mode. I never could understand (other than the hardware requirements) how it was better than packet with its error correction ability.
 

jhooten

Member
Joined
Mar 6, 2004
Messages
1,381
Location
Paige, Republic of Texas
Finding an unused frequency? "Is this frequency in use?" a couple times on FM voice might do the trick. A few "QRL QRL? de xx#xx" on RTTY might do the trick.

My guess is that as long as you aren't on a typical simplex freq (146.52, 146.535, 146.55, 146.565, 146.58), on a repeater input/output, on 144.39, or on the typical packet freqs, you aren't going to run into frequencies that are in use. Plenty of spectrum left to run RTTY on.

Hell, in most areas you won't even hear packet anymore.

Mike
144.39 would really get the APRS types panties in a big wad.
 

Nap

Member
Joined
Sep 10, 2011
Messages
142
Location
Ontario
I have no idea what the "Gentlemens agreements" allow, but my first thought would be "Who Cares" if it is frowned upon.

Amateur radio was created by people experimenting. Experimentation has been the single largest driving factor in amateur radio in the past.
Mostly agreed with two notable exceptions:

1. On VHF/UHF there are lots of FM repeaters, and you don't really want to place your transmission on a repeater input frequency; otherwise you'll have the whole local radio club after you. Also UHF is secondary for amateur radio, if you interfere with something like a local radar it won't be fun either.

2. It is futile to try to argue with the ex-CBer with an 1.5 kW amplifier and a Texas tower. So better start the experimenting somewhere where he wouldn't notice you otherwise you'll get interrupted and your fun spoiled.
 

wb0wao

Member
Joined
Apr 29, 2008
Messages
328
Location
Cape Girardeau, MO
Back "in the day" - mid to late '70's - the 10/70 pair was commonly used for RTTY repeaters. There was a 10/70 machine in Kansas City that routinely had RTTY on it as well as voice.
 
Status
Not open for further replies.
Top