PDA

View Full Version : FCC grants a waiver allowing hams to use TDMA



K6BSO
03-25-2013, 10:47 AM
At the request of the ARRL, the FCC has granted a temporary "waiver to permit amateur stations to transmit communications on amateur service channels above 30 MHz using single time-slot Time Division Multiple Access (TDMA)."

I don't know if this is a good thing or not. Anyone care to comment?

Full text available here (hraunfoss.fcc.gov/edocs_public/attachmatch/DA-13-542A1.pdf) in PDF form.

K7SGJ
03-25-2013, 11:03 AM
It will be interesting to see what kind of equipment, surplus as well as new, becomes available. I'm not too sure I'm a fan of this, or not. I'll be curious to see how it shakes out.

If nothing else, it will give a whole new dimension to the whiners on the other sites. Lessseee, no code, winlink, CB, IRLP, contests, and now this? Shit, they're going to have to start a new section just to accommodate all the bitching and moaning.

I can see it now, TDMA is not real ham radio.

kb2vxa
03-25-2013, 04:38 PM
Sorry if I just don't get it. If TDMA divides time into slots and separate the signals of different users by placing the signals in separate time slots, how is single slot any different than a standard repeater? Motorola offers a system with single slot portables and a two slot repeater, it makes sense that there may be two simultaneous users on the system and with multiple repeater slots more users may be accommodated. To me if the FCC only authorizes single slot it's useless as tits on a bull being one user at a time is no improvement in communications effectiveness and no more efficient use of spectrum.

So what about this I don't understand? BTW I see the advantage TDMA has over trunking, it uses one frequency while trunking uses several to accomplish essentially the same thing, efficient use of spectrum.

"I can see it now, TDMA is not real ham radio."

Of course not, it's 2G cell phone technology. (;->)

AE1PT
03-25-2013, 07:31 PM
Don't try to understand it. It's not ham radio, but an attempt by the clueless no-coders to recycle their old analog cell phones as talkies on our bands--bringing us all to the intelligence of CBers and the end of the world as we know it.

W7XF
04-05-2013, 02:18 PM
IB4TS



(In bofore Teh Stoopid

K7SGJ
04-05-2013, 10:13 PM
IB4TS



(In bofore Teh Stoopid

Too late.

W7XF
04-06-2013, 11:49 AM
Too late.i noticed

KC2UGV
04-06-2013, 08:47 PM
The FCC needs to get with the times, and stop regulating by mode, and instead regulate by bandwidth of the signal. Hams should be allowed to use CDMA, TDMA, etc, as long as it's not encrypted. Narrower bandwidth signals get the lower freqs, and wider signals on the upper freqs; and spread down the middle.

kb2vxa
04-07-2013, 10:51 AM
I knew a girl like that.......
Actually the FCC already regulates by bandwidth, phone signals for example are limited by the highest audio frequency which determines occupied bandwidth. That's why the ESSB ops got busted for not keeping highs below the customary 3KHz. AM is limited to 6KHz bandwidth which makes legal ops sound kinda yellowy with that 300Hz-3KHz telephonium yawdio. When it comes to data modes, basically occupied bandwidth is a function of data rate so the upper limit is specified. This saves operators the trouble of calculating whether or not the intended data rate meets or exceeds the bandwidth limits. Bandwidth is not specified on the microwave bands so progressive packet nodes/BBSes use high speed microwave forwarding links.

WTKX
04-07-2013, 02:38 PM
Huh? Show me where ESSB ops with a wide clean signal get busted? Many AM folks run 12 Khz wide. I have run 6khz wide with a clean signal, but only if I don't bother the "neighbors". I use the panadaptor view on the Flex, so I can see what is going on.

Don't do it often, as it's not efficient. 4Khz gives me a great "HiFi Voodoo" sound, but I usually run at about 2khz wide +/-, especially if I am not running an amp, tailored to my voice characteristics. If I'm ragchewing with an ESSB group I will bring up problems with other's wide signals... too much bass is stupid, unless you sound like Harvey Fierstein. :lol:


http://youtu.be/5D_vvsiJUxw


http://youtu.be/5D_vvsiJUxw

kb2vxa
04-07-2013, 03:55 PM
"Show me where ESSB ops with a wide clean signal get busted?"

Unfortunately time has intervened and the NALs are deeply buried in the FCC archives or may have been deleted. I remember a group in Bergen County, NJ on 20M that got busted back in the late '90s, I wouldn't lie but if you refuse to take me at my word I really don't care.

"Many AM folks run 12 Khz wide."

I've been aware of the AM Gangstas in the 75M window have been doing it for decades and I've not heard of any getting busted. Then there's Timtron, Sir Riley of Hollingsworth wrote a warning about his "testicling" that was rather funny but I digress. There are plenty of hams running re-tuned hollow state AM broadcast transmitters that pass typically up to 7.5KHz audio making them 15KHz wide and I know a certain Johnson Valiant modified for 600 ohm balanced line level audio that tested out to 11KHz before modulation rolls off, all reports on the audio FB. Oh, using an FM peak limiter with 75uS pre-emph helps a bit. (;->)

Conclusion: Yay Emmers complain about the slopbucketeers but they get along with each other famously. On the other hand the ESSB crowd generally doesn't play well with the neighbors, some go WAY overboard with EQ and processing like a broadcast station never sees. Well, some use hammers and cheese graters, they sound like shit but I digress. You should know the FCC by now, they don't monitor the ham bands except Riley is a ham who joins in and you have to light a fire under them just to get them to take notice. Bottom line, hams on 20M lit the fire.

"I have run 6khz wide with a clean signal, but only if I don't bother the "neighbors"."

More power to you, up to 1500W that is. Good neighbors don't get complaints, that's the way it's always been.

WTKX
04-07-2013, 04:25 PM
Sorry I gave the impression that I thought you were lying, WTF?

:shifty:

OTH, I run 1.8-2K wide tailored to my voice, and that kicks ass in difficult conditions... Which is almost always on 75 meters. :lol:

KC2UGV
04-07-2013, 07:33 PM
Exactly my point, gents. A 12KHz wide signal on a 160 is ridiculous, while a 3KHz signal on 440MHz is banned, because of it's emission type.

WTKX
04-07-2013, 09:32 PM
Yup... Although 160 has a lot of unused space most of the time.

kb2vxa
04-08-2013, 04:02 PM
"Sorry I gave the impression that I thought you were lying, WTF?"

No big deal, but with all the "links or you're lying" BS around here...

"...difficult conditions... Which is almost always on 75 meters."

It's not so much a crowded band but rather what it's crowded with.

"A 12KHz wide signal on a 160 is ridiculous..."

Only to those lacking a proper receiver designed for the purpose and a good monitor speaker, with an SSB receiver and tin box speaker you can't hear the Angel Music.

"Yup... Although 160 has a lot of unused space most of the time."

Exactly, the AM window isn't exactly a crowded house, you don't have neighbors to disturb. Even with neighbors, audio processed just right with no distortion products doesn't splatter so just like the AM broadcast band in the pre IBOC days you can fit stations every 10KHz with no problem. Speaking of AM broadcast, 160M is where plenty of junked tube type broadcast transmitters showed up being those made for the top of the band are easily tuned anywhere from 1MHz to 3Mhz without modification.

Then there's that previously mentioned Valiant fed by the audio rack that proofed out to 11KHz @ 100% modulation before rolling off, in the 40M AM window it got FB reports and no complaints. (heh heh heh)

KC2UGV
04-09-2013, 06:26 AM
""A 12KHz wide signal on a 160 is ridiculous..."

Only to those lacking a proper receiver designed for the purpose and a good monitor speaker, with an SSB receiver and tin box speaker you can't hear the Angel Music.


Then why not allow a 12KHz wide digital signal on the same band?

KC9SQR
04-10-2013, 01:14 AM
Don't try to understand it. It's not ham radio, but an attempt by the clueless no-coders to recycle their old analog cell phones as talkies on our bands--bringing us all to the intelligence of CBers and the end of the world as we know it.

I'm still trying to figure out what this has to do with cell phones and ham radio.. I do get what this ruling has to do with ham radio, just not analog cell phones...
I could be wrong, but I've never known TDMA to be analog...
I'm also unsure of how to reband a cell phone or how to simplex with one without a tower...

Are you referring to the Nextel off network Direct Talk 900 mhz PTT?
If so, this doesn't apply to those. Those use FHSS and are digital.. Not much would be needed to make them part 97 compliant as FHSS has been allowed for a while, and they stay within 902-928 MHZ.. Unless I'm mistaken which I could be, wouldn't be the first, and damn sure won't be the last I'm sure lol...

kb2vxa
04-10-2013, 06:52 PM
"A 12KHz wide signal on a 160 is ridiculous... Then why not allow a 12KHz wide digital signal on the same band?"

Did I say it was allowed? If I did please feel free to point it out in a quote.

"I'm still trying to figure out what this has to do with cell phones and ham radio.. I do get what this ruling has to do with ham radio, just not analog cell phones... I could be wrong, but I've never known TDMA to be analog..."

Two "channel" TDMA is G2 cell phone technology used on some Motorola VHF/UHF communications systems to put two separate channels, usually one data and one voice on a single carrier. Multichannel TDMA puts more on one carrier, all digital allowing many simultaneous users on a single RF channel. Both are more efficient use of spectrum than one user or user group per channel like a repeater and the new ruling is exactly the same thing, certainly NOT more efficient use of spectrum. That's why right from the start of this thread I've been saying it makes no sense.

"Are you referring to the Nextel off network Direct Talk 900 mhz PTT?"

No, actually it's on the network or units couldn't communicate at a distance but I don't know how it works, just that it does. FYI Nextel is going bye bye as early as next June. I don't know what this next generation Direct Connect is they're migrating to but here it is from the horse's mouth. http://newsroom.sprint.com/article_display.cfm?article_id=2296

KC9SQR
04-10-2013, 08:03 PM
"A 12KHz wide signal on a 160 is ridiculous... Then why not allow a 12KHz wide digital signal on the same band?"

Did I say it was allowed? If I did please feel free to point it out in a quote.

"I'm still trying to figure out what this has to do with cell phones and ham radio.. I do get what this ruling has to do with ham radio, just not analog cell phones... I could be wrong, but I've never known TDMA to be analog..."

Two "channel" TDMA is G2 cell phone technology used on some Motorola VHF/UHF communications systems to put two separate channels, usually one data and one voice on a single carrier. Multichannel TDMA puts more on one carrier, all digital allowing many simultaneous users on a single RF channel. Both are more efficient use of spectrum than one user or user group per channel like a repeater and the new ruling is exactly the same thing, certainly NOT more efficient use of spectrum. That's why right from the start of this thread I've been saying it makes no sense.

"Are you referring to the Nextel off network Direct Talk 900 mhz PTT?"

No, actually it's on the network or units couldn't communicate at a distance but I don't know how it works, just that it does. FYI Nextel is going bye bye as early as next June. I don't know what this next generation Direct Connect is they're migrating to but here it is from the horse's mouth. http://newsroom.sprint.com/article_display.cfm?article_id=2296

Thanks :)
I have a pretty good idea on how TDMA works, which is why I was, and still am still trying to figure out AE1PT's comment about this being about no coders wanting to bring their old analog cell phones to be used as walkie talkies on our bands...

I also have heard about the Sprint/Nextel killing off what's left of their IDEN network.. That will make the Direct Connect or anything on the IDEN handsets not work anymore. But certain models (quite a few actually) have an off network PTT mode called Direct Talk or "Mototalk". Which is a 900 mhz FHSS digital two way radio.. It only works with other "Mototalk" handsets that are specifically in that off network mode and on the same "channel and code"..

They only output 600 Milliwatts but they are impressive, I have a pair I've played around with and in a somewhat dense city environment I've actually gotten 2+ miles out of these things.. I wasn't sure if that's what AE1PT was referring to or not...

I'm also a bit disappointed that they're not allowing the 2 slot division system... Kind of defeats the purpose of what it's intended to do... Which makes me wonder, I've been told you're allowed to run that similar mode on other modulations on the ham bands.. Dstar, DMR, and p25... Unless I was misinformed (which I wouldn't be surprised) I wonder why those can do 2 slot but TDMA isn't being allowed basically the same thing... Actually isn't DMR based off of TDMA? I've heard of DMR being used on ham bands, I haven't seen it used, but I'm willing to bet they're using voice/data setup, or 2 slot voice..

In reality the way I see it, TDMA is only being "half allowed" lol

I forgot to add a link for more information on "Mototalk"
http://en.wikipedia.org/wiki/MOTO_Talk

And here's a list of the compatible handsets for that off network mode I mentioned..
BTW I'm not really interested in trying to use these things with any ham privileges, I just think they're kind of neat and have some potential behind them

MOTO Talk is available on these iDEN models:


i680 (http://en.wikipedia.org/w/index.php?title=Motorola_i680&action=edit&redlink=1)
ic902 (http://en.wikipedia.org/w/index.php?title=Motorola_ic902&action=edit&redlink=1)
i880 (http://en.wikipedia.org/w/index.php?title=Motorola_i880&action=edit&redlink=1)
i870 (http://en.wikipedia.org/wiki/Motorola_i870)
i850 (http://en.wikipedia.org/w/index.php?title=Motorola_i850&action=edit&redlink=1)
i760 (http://en.wikipedia.org/wiki/Motorola_i760)
i670 (http://en.wikipedia.org/w/index.php?title=Motorola_i670&action=edit&redlink=1)
i580 (http://en.wikipedia.org/w/index.php?title=Motorola_i580&action=edit&redlink=1)
i560 (http://en.wikipedia.org/w/index.php?title=Motorola_i560&action=edit&redlink=1)
ic502 (http://en.wikipedia.org/w/index.php?title=Motorola_ic502&action=edit&redlink=1)
ic402 (http://en.wikipedia.org/w/index.php?title=Motorola_ic402&action=edit&redlink=1)
i315 (http://en.wikipedia.org/w/index.php?title=Motorola_i315&action=edit&redlink=1)
i355 (http://en.wikipedia.org/w/index.php?title=Motorola_i355&action=edit&redlink=1)
i365 (http://en.wikipedia.org/w/index.php?title=Motorola_i365&action=edit&redlink=1)
i325is (http://en.wikipedia.org/w/index.php?title=Motorola_i325is&action=edit&redlink=1)
i275 (http://en.wikipedia.org/w/index.php?title=Motorola_i275&action=edit&redlink=1)
i9 (http://en.wikipedia.org/w/index.php?title=Motorola_i9&action=edit&redlink=1)
M710
i425
i576
r765, r765is
i570
i786
i776
i465
i296
i335

KC2UGV
04-11-2013, 06:37 AM
"A 12KHz wide signal on a 160 is ridiculous... Then why not allow a 12KHz wide digital signal on the same band?"

Did I say it was allowed? If I did please feel free to point it out in a quote.


You don't have to say a 12KHz signal is allowed on 160m. It is. As long as it's an approved emission type (ie, AM, ESSB, SSB, etc etc), it is.

kb2vxa
04-11-2013, 06:41 AM
"...and still am still trying to figure out AE1PT's comment about this being about no coders wanting to bring their old analog cell phones to be used as walkie talkies on our bands."

In a word; sarcasm.

"I'm also a bit disappointed that they're not allowing the 2 slot division system... Kind of defeats the purpose of what it's intended to do..."

My point entirely, I don't see a bandwidth issue here but I may be blind, why not more than two slots? I can see repeaters with multiple "talk groups" on a single RF channel which would curtail the all too comon repeater glut in major metropolitan areas. With fewer repeaters they wouldn't resort to simplex channel takeover, that is for example on 2M they use a 1MHz split instead of the normal 600KHz. That reminds me of a few years ago the battle between LIMARC (Long Island Mobile ARC) and a couple of OTs operating simplex on a repeater input thinking it was still a simplex channel. Oh boy were they pissed that a repeater took over their old favorite frequency but being a coordinated repeater you know who won that one. Meanwhile the OTA battle was quite funny.

"Actually isn't DMR based off of TDMA?"

What's DMR?

"You don't have to say a 12KHz signal is allowed on 160m. It is. As long as it's an approved emission type (ie, AM, ESSB, SSB, etc etc), it is."

HUH? Last I read the rules max bandwidth for AM is 6KHz, SSB 3KHz and ESSB is a violation that has been successfully prosecuted. I'm not about going over that wide band sideband crowd in Bergen County, NJ again, I've mentioned it enough times you should know all about it by now. There was another rather recent case posted in these forums, do your homework before you spew misinformation please. Oh, if you want to retort it would be helpful to state the approved 12KHz bandwidth emission type since "etc. etc. etc." means less than nothing.

I really should be keeping track of how many times you contradict me for contradiction's sake pulling "facts" out of thin air, the running tally would add a few chuckles.

KC9SQR
04-11-2013, 11:57 AM
<snip>

"Actually isn't DMR based off of TDMA?"

What's DMR?
<snip>


Digital Mobile Radio..
"The DMR standard operates within the existing 12.5 kHz channel spacing (http://en.wikipedia.org/wiki/Channel_spacing) used in land mobile frequency bands globally. Its primary goal is to specify a digital system with low complexity, low cost and interoperability across brands, so radio communications purchasers are not locked in to a proprietary solution. DMR provides voice, data and other supplementary services. DMR is a two-slot,time division multiple access (http://en.wikipedia.org/wiki/Time_division_multiple_access) (TDMA) system offering voice, data and a range of other features and applications. The specification covers the RF frequency range 30 MHz to 1 GHz and uses 4 level FSK (http://en.wikipedia.org/wiki/Frequency-shift_keying) constant envelope modulation."

I hate using wikipedia for examples, but it provides the most information on DMR in one spot.. BTW it's also known as MOTOTRBO
http://en.wikipedia.org/wiki/Digital_mobile_radio

as well as http://www.dmr-marc.net/

From what I gather, groups such as the 2nd link have been running DMR, which is TDMA.. On the ham bands for a while before this recent ruling half allowing TDMA on our ham bands.. Good thing the FCC doesn't care about the ham bands eh? :doh:

WTKX
04-11-2013, 12:08 PM
:lol: There is NO bandwidth limitation for AM or SSB phone. :snooty:

With the obvious exception of 60 meters.

KC2UGV
04-11-2013, 12:29 PM
"You don't have to say a 12KHz signal is allowed on 160m. It is. As long as it's an approved emission type (ie, AM, ESSB, SSB, etc etc), it is."

HUH? Last I read the rules max bandwidth for AM is 6KHz, SSB 3KHz and ESSB is a violation that has been successfully prosecuted. I'm not about going over that wide band sideband crowd in Bergen County, NJ again, I've mentioned it enough times you should know all about it by now. There was another rather recent case posted in these forums, do your homework before you spew misinformation please. Oh, if you want to retort it would be helpful to state the approved 12KHz bandwidth emission type since "etc. etc. etc." means less than nothing.

I really should be keeping track of how many times you contradict me for contradiction's sake pulling "facts" out of thin air, the running tally would add a few chuckles.

There is no bandwidth limit for AM or ESSB (Or, PSK, or any other approved emission type), shy of on 60 meters. The only limit is "that which is required for reliable communication", and that's it.

Now, I will be more than happy to cede the point to you, if you can point out where in Part 97 bandwidth is limited anywhere other than 60 meters.

WTKX
04-11-2013, 12:54 PM
Never called anybody a liar on this issue, though we do have some obvious liars on Hamis regarding other issues.

Just misinformed, and/or mistaken. Here ya go... FETCH!

http://www.arrl.org/files/file/Regulatory/Part%2097%20-%2004-28-2011.pdf

Here is another place for enlightenment. (http://www.nu9n.com/apologetics_2.html#a2)



Some have argued that "J3E" formerly known as "A3J" is a 3kHz SSB mode by definition. This is false information! The FCC has defined many modes using a proprietary alphanumerical designator that somewhat describes the nature, usage and bandwidth of the signal. "J3E" is really only the latter part of a more complete designator as defined in FCC part 2-201 and ITU-2 (http://www.nu9n.com/images/Part2-201.pdf).

Broken down, "J3E" means the following:
J - Single sideband, suppressed carrier
3 - A single channel containing analog information.
E - Telephony (Phone / Voice)

No mention of occupied bandwidth is included in this naming scheme. However, a trip to Part 2-201 (http://www.nu9n.com/images/Part2-201.pdf) expands the designator by four more digits that precede the three above.

Example of a full alphanumerical designator is as follows:

3K00J3E

In this example, the first four characters: 3, K, 0 and 0 represent the specific bandwidth of the mode being used which in this case means 3.00 kHz. The number before the "K" represents the number of thousands of Hz and the numbers after the "K" represents the number of hundreds and tens of Hz, with the "K" representing the decimal separating the thousands from the hundreds as a decimal place holder. A 4kHz SSB mode would be designated as 4K00J3E. A 4.5kHz signal would be designated as 4K50J3E, etc... Therefore, J3E could have a number of different bandwidth possibilities. In other words, the mode designator does not determine the bandwidth, but rather the reverse! The bandwidth determines the alphanumeric designator for mode specific identification purposes!





"Hi-fi SSB is not consistent with FCC defined 'Good Amateur Practice' mandates."



Although we have already covered this in part, it deserves more attention. "Good amateur practice" is inclusive of all aspects of amateur radio. To me, this means operating cleanly, being polite, non-judgmental, forgiving, courteous, responsible, understanding, encouraging - in short, exercising the "Golden Rule" when it pertains to our conduct with others.

There is no inconsistency using Hi-fi SSB (eSSB) when the attitudes above are employed. It is no more "immoral" or "unethical" generating a high quality eSSB signal than it is generating a highly processed narrow "DX" signal if the attitudes of the operators are peaceful.

Good amateur practice is the use of the VFO to find peace instead of the PTT to start World War III.




4
"Hi-fi SSB is illegal as defined by the FCC 'Minimum Necessary Bandwidth' rule."



There are no SSB bandwidth restriction or limitations as defined by the FCC.

This has been the subject of debated ever since the Hi-fi SSB movement was started.

Nowhere in Part 97 are hard numbers specified regarding telephony bandwidth for SSB or AM.

The "minimum necessary bandwidth" rule, as reviewed earlier, is again dependent on what you consider is "necessary". This terminology is open to a variety of interpretations based on presuppositions about where you already stand on the bandwidth issue. It is always tempting to interpret rules according to a personal position rather than vice-versa.


What I am convinced is happening when someone makes a claim that an eSSB signal is 9 or 10kHz wide is an error when calculating the total bandwidth. They erroneously include their receiver's passband width in the count.

Let me explain using an example: If you put your receiver on say 14.100 USB and zero-beat a CW signal and then tune up frequency until the signal disappears, you will find the CW signal gone after about 32Hz at 14.103. This would determine the total bandwidth of the signal in question. However, if you tune down in frequency, you will hear the CW signal as far as the filter width in your receiver will allow. So, if you had a filter bandpass of 4kHz selected, you would hear the CW signal 4kHz below zero beat. Does this mean then that the CW signal is 32Hz plus 4kHz wide totaling 4032Hz? No Way!!! Your receiver's band pass is allowing you to hear it, but this is not how to measure the bandwidth of the signal.

The receiver's bandpass in the opposite direction does not count when measure the bandwidth of an SSB signal any more than it does when measuring the bandwidth of a CW signal as demonstrated above! So, when measuring an SSB signal's bandwidth, you MUST ONLY measure what you can hear in the direction of the selected sideband; If measuring USB, then tune up and do not count what is below the suppressed carrier baseline. For LSB, it is the reverse. The "10k" report occurs when someone is including the 4kHz bandpass of their receiver in the opposite direction of the 6kHz signal being measured. They think that this therefore means they are measuring 10kHz, when in fact they are only measuring 6kHz plus the 4kHz of their own receiver's bandpass selection.

Quite honestly, I have not ran across to many operators who even know how to accurately determine someone's RF transmit bandwidth. Again, when I hear someone tell me that I am "9kHz wide", I know that they are including their 3kHz of receiver bandwidth when they tuned the extra 3kHz on the opposite side of the carrier frequency.

Also, signal strengths above S9 in the order of 20dB/9 or above complicate matters when receiver rejection (or the lack of it) comes into the equation. A good quality HP RF spectral analyzer can cost thousands of dollars. And even with an accurate measuring device, great care must be exercised when doing measurements and evaluating the RF bandwidth of someone's signal. I'm sorry, but an ICOM band "pan" display is not even close to being any type of a serious RF spectrum analyzer. It's pretty and gives you a rough idea where band activity is occurring, but that's about it.

kb2vxa
04-11-2013, 01:42 PM
I've seen MOTOTRBO listed on scanner sites on the internet but that's about the extent of my knowledge on the subject. There's a better reason why it's not been detected on the ham bands, I haven't seen any software able to decode it and the FCC dismantled their monitoring sites decades ago. Being in use it's a hardware thing, that is radios so equipped and as we all know modern digital memories can be programmed for the ham bands without physical modification. That BTW started around the time the Motorola Syntor was introduced, I knew a ham who was employed by the NJ Turnpike Authority who had a bank of them with various VHF ham frequencies programmed along with Turnpike frequencies in his service truck.

OK, while there may be no bandwidth limits per se it is understood by hams and the FCC "that which is required for reliable communication" is as I stated above. I stand by my statement about the ESSB crowd in Bergen County getting busted, I heard the QRM they caused on the air and read the FCC notices so nobody will ever convince me that nobody gets busted for bandwidth in excess of that required for reliable communication. If nothing else the AM Gangstas are considerate of others, when the windows get crowded they reduce high frequency modulation accordingly.

As an aside, I've posted pictures of K2PG Phil's broadcast transmitters on 160 and the audio console with the R-390 receiver next to it but he never put pictures of the audio rack or the Valiant (the Drake and Collins stations either) on his web site. He was planning to use the Kahn AM stereo exciter in the bottom of the rack but never got around to it. Courtesy was his intent, being ISB with full carrier it can emphasize one sideband over the other thus protecting stations on one side or the other 5KHz away. Yeah, the AM windows around the bands are channelized every 5KHz ending in 0 or 5 and frequencies are respected, no sliding up against the other guy. Too bad Kahn got lobbied out and the FCC adopted the Motorola system as standard, but this allowed hams with big transmitters to salvage them from the scrap heap as they did with the transmitters. Like the transmitters all that's required to put them on 160 are a crystal and a screwdriver.

If your tubes don't glow you're not feeding them enough POWER!

KC9SQR
04-11-2013, 02:11 PM
http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)

Actually there IS something to decode it! :)
I've had really good luck with the windows port of this software, I really suggest at least checking it out..
Just using a discriminator tap off of my 8800 it decodes p25 and Mototrbo nicely.. Those are the 2 I've come across so far anyways...