Saturday, June 13, 2009

D-Star Simplex Station

Ok first off I promise not to turn into a D-Star fanatic. Nothing has urked me more lately than the D-Star hype fanatics. The most recent example is this D-Star newsletter.

D-Star isn't for everyone, nor is it the saving grace of amateur radio. Bombarding folks with growth (peer pressure) statistics from isn't cool kids.

To me; D-Star overall is Disappointment-Star. My feeling are that ham radio needs narrow band like the ARRL needs aging members. But that's no fault of D-Star's design, more so of our bandplans. D-Star was designed to work into existing ham band plans.

So why did I pick up a D-Star radio you may be wondering? Simple, it's emerging technology and experimenting with that sort of thing is right up my alley. It was hard to justify because the local big radio club around here will spend grant money on foolish redundant equipment that only gets used occasionally. But the concept of trying to define and set the pace for the areas ham radio future by deploying new infrastructure is apparently beyond them. (IMHO a CW and spark gap forever mentality.)

I've shared my thoughts before on the enormous amount of development potential there is with D-Star despite it's utterly useless low bit rate. Enhancing the no-frills controller, and a SIP to D-Star translation for IP telephony interconnection.

However that's all stuff a bit beyond what one or two guys with a HT can start messing with.

So what I have been throwing a few ideas around with and messing with some code that is doing things with the receive callsign heard data as a simplex station. Bruce, KG7WI has a nice perl routine for to get and put data from/to an IC-91AD that can be adapted for the IC-92AD as well.

The concept is, since each user transmission contains a callsign, we are able to create custom greetings based off decoded data, by using a text to speech engine such as Cepstral or Festival. "Welcome KB9MWR to the N9DKH simplex station." "You have one voice mail message from Kevin, left yesterday"... A relational database or QRZ lookup could even make it more personal with first name greetings. Last heard callsign stats could be kept and queried via touch tones and/or exported to a club webpage. D-Star low speed short messages could be posted to twitter for those hams who don't have a HT genetically attached to their hip at all times. And so much more...

To make this interactive, I was hoping the digitized DTMF would be available via CI-V. This is not the case, so they will have to be decoded externally-analog style.

Other ideas include reposting the received short text messages once can send from their radio to twitter. Or reporting recent heard - on the air status messages to twitter.

Icom could share the CI-V command codes, which could them sell D-Star, as more excitement there would be generated and people using the D-Star radios. But so far there hasn't been any openly published for this particular radio. A true bummer, as well as their choice to deny a fairly major radio issue. Those are bad business moves in my book.

Saturday, June 6, 2009

Are you narrow or wide?

Recently our local repeater coordinator began asking your emission designator on the application form. A break-down of emission designators can be found in section 2.201 of the telecommunications part of the code of federal regulations.

20K0F3E - FM Voice 20kHz bandwidth - Wide 
16K0F3E - FM Voice 16kHz bandwidth - Narrow
11K2F3E - FM Voice 11.2kHz bandwidth
8K10F1E - P25, phase 1, 12.5kHz Bandwidth
5K76G1E - P25, phase 2, 6.25kHz Bandwidth
6K00F7W - D-Star, 6kHz bandwidth

The confusion I often see lies whether a system is narrow or wide. 20 KHz bandwidth or 16 KHz. To determine this we must look at Carson's bandwidth rule.

As you can see in the analog world, your bandwidth will be determined by transmitter deviation. If you have 5 KHz deviation (now a days considered wide band I guess) you will occupy 20kHz of bandwidth. If your deviation is in the 2-3 KHz area you will occupy 16kHz bandwidth now referred to as narrow FM.

Now a days wide / narrow transmitter deviation is usually a software selectable option. The quote/unquote standard for ham radio has been 5KHz max deviation/20kHz bandwidth.

If you can't determine by software/programming configuration you'll likely need access to a deviation meter or service monitor to determine your deviation.

+/-2.5kHz maximum deviation is also a standard for 800 MHz and above and has been since the mid 90's. This is why you typically see 12.5kHz channel spacing up there. Actually I have never seen any Wide analog FM above 800 MHz except on remote broadcast studio-transmitter links. 

So if nothing else use the mid 1990's as a date of determination. If we are talking VHF/UHF commercial equipment manufactured 1997 or more recently you can probably assume it's "narrow FM"/Max 3 KHz deviation - yielding 16kHz bandwidth. Another clue is if it was in commercial service using a 12.5 kHz step/channel spacing scheme, it is likely narrow FM.

Here is the history: 
A process of "refarming" the informal name of a notice and comment rule-making proceeding (PR Docket No. 92-235) opened in 1992 to develop an overall strategy for using the spectrum in the private land mobile radio (PLMR) allocations more efficiently to meet future communications requirements. The FCC created mandates for the two-way radio equipment manufacturers. In 1997, all new two-way radio models had to be capable of operation on the "new 12.5 kHz narrowband" channels. This is often called "dual-mode" equipment since the radio can accommodate both narrow- and wide-band channels. The idea was to begin to move gently toward narrowband channel operation over time. At that time, the FCC did not create any mandates to remove older wideband radio units from service or require you to use a new narrowband channel.
The Part 90 LMR narrowbanding mandate was released 12-23-2004 by the FCC for all Part 90 business, educational, industrial, public safety, and local and state government two way radio system licensees currently operating legacy "wideband" (25 KHz) voice or data/SCADA radio systems in the 150-174 MHz (VHF) and 421-512 MHz (UHF) bands. The executive summary of the FCC order  establishes January 1, 2013 deadline for migration to 12.5 KHz technology.

(Note many ham HT's are capable of WFM / Wide FM receive, intended for reception of FM radio/ Analog TV audio. Don't confuse this with the two way standard... Broadcast Wide FM is 150 KHz of bandwith.)

True narrowbanding a receiver is what is hard.  I am talking narrowing the receiver IF bandwidth.

Just be aware that converting a 1950's era repeater to D-Star or P-25 that might have a 60 Khz I.F. would be vulnerable to adjacent channel interference. A good overview of the theory can be found in a reprinted article from Ham Radio Magazine 1985, by WD5IBS.

Monday, June 1, 2009

Revisting ham radios image and marketing

My first blog was about creating a more modern image for the hobby.

What I have noticed is that the oldest advertising and marketing trick in the book, using the sex appeal has significantly dropped off in the hobby. About the only really prominent in practice example are the Icom girls.

Going back looking at some older material, I have to hand it to Wayne Green, publisher of 73 magazine. He not only knew how to market his publications, but he knew how to inspire. That is something noticeably absent in ARRL publications.

Observations as of recent years show there are some operators who really are cutting-edge, advancing the state of the art and all … But on the whole there are way too many hams who are woefully inadequate in technologies that are already mainstream, and that most employable people are expected to be proficient with.

Sad but true. Instead of inspiring hams and using old marketing techniques to get their attention and sell stuff, the latest trend seems to be the Emcomm push.

But when it comes to creating a good image and turning hams off I have to say there are number of old school practices that really need to go, or at least be revisited.

Burt,  K1OIK comes off a bit cranky in some of his youtube video rants, however if you can get past his cynicism, he does have some very valid observations.

Truth revealed about ham radio; The Real World Of Ham Radio; and, Ham radio, a critical evaluation.

Yes I am suggesting that some of these old school formalities are entering the lid category. Speaking of lid, I'm fairly thick skinned but I have had to lock a channel or two out of my scanner to a local lid who refers to himself in the plural sense much to often.


31) Make people think you have a split personality by referring to yourself in the plural sense. When you're in conversation and are alone at your radio, always say "We're" or "We've" instead of "I'm" or "I've" (i.e. "we've been doing this...", "we're doing that...", "we're clear"). Everyone knows you're by yourself, but when they ask you who is with you, make up somebody important like Arnold Schwarzenegger or Bill Clinton.

Now getting back to the whole Emcomm push. You may have noticed that basically the ARRL directors come off as a bunch of ambulance chasers. This mentality is also used to help suggest "new"(cough) technologies for the hobby that such persons/ groups feel need to be implemented. An example is the ARES Winlink push. And now I see Icom has some nifty little PDF's along the same line trying to promote D-Star the same way. All this Emcomm/ARES mystique stupidity of course is prompted by money. A push for ham clubs can apply for grants to be able to implement such "new" technologies.

I feel that Ham radio does not need to become a back-up for the internet and other commercial IP communications. Nor does ham radio need to be a backup for voice communications. This is a hobby for experimentation and learning. Sadly there aren't many old school guys left that want to learn and experiment. Most people come here for "fun"? Which explains why most newly licensed hams go inactive in a short amount of time. The EmComm backup communications business is directly related to the huge frequency allocations that we are squating on. This is justified if we can provide backup communications and dedicate time to civic ARES/RACES exercises.

Just recently Google has Urged a National Inventory of Radio Spectrum. The worst part is that most hams and the ARRL won't put up an argument because they see this as no loss as there is little ham radio activity on these bands.