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Old 11-15-2013, 03:47 PM
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DaveInDenver DaveInDenver is offline
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Default Digital Radio

Several people on here use APRS and I think a couple of mentioned IRLP. But no one has ever mentioned true digital voice and data. KC0YRM once mentioned that he was considering an D-STAR.

I sold that FT-8800 and now am looking for a new dual bander. I have a FTM-350 that I like a lot and so the FTM-400 was high on the list.



However thinking more about and weighing options for the same money I could do a IC-2820H with the UT-123 D-STAR & GPS. It lacks the APRS features, though it supports a digital mode with some existing infrastructure. Plus it's not difficult to add a TNC to it and do APRS in the background like the FTM-350, FTM-400 and TM-D710.



Of course the 3rd option is the TM-D710. No digital modes but probably the best APRS option.



So who already has or is considering something digital? I'm not enthusiastic about another protocol that Yaesu uses, but don't think D-STAR is all that. If at least a few people get Yaesu digital radios even without a lot of infrastructure the simplex features are nice compared to what ICOM offers with D-STAR. OTOH if D-STAR even looks interesting to a few people then I'll consider the ICOM.
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Old 11-16-2013, 08:16 AM
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Meh--DSTAR.
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Old 11-16-2013, 08:55 AM
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Quote:
Originally Posted by Mendocino View Post
Meh--DSTAR.
Why do you say that? Is it because it's GMSK, thus 'ancient' technology? I couldn't say if it'll grow any more but about 10% of the repeaters in the U.S. are D-STAR currently, which is around 750 of them. There are approximately 30,000 call signs registered and I think about 1,500 repeaters total. There is a D-STAR amateur microsat (OUFTI-1).

This blows away Yaesu at zero (since no network or gateways yet exist) and DMR-MARC (MotoTRBO) at 411 repeaters worldwide and 4,100 IDs.

I wish Yaesu would not have implemented FDMA first but rather gone straight to TDMA. And I /definitely/ wish they would not have spec'd AMBE+2 for the vocoder and gone with Codec2 instead. But at least setting up a repeater and the individual radios don't require unit registering as it does with commercial DMR systems.

I can't see any commercial derived DMR getting much traction when you can set up a D-STAR repeater for under $1,000, probably 1/3 what surplus Motorola gear costs, not to even think about a new repeater. Even a brand new Yaesu DR-1 is going to be doable for a club. If Yeasu does what ICOM does they sell repeaters at cost or even free them away to clubs interested in setting up a D-STAR repeater (if only, ICOM will GIVE you a repeater and a few D-STAR HTs if you ask) I wouldn't be surprised if Yaesu's digital gets some installations pretty quickly.

So I'm still not sure where to plunk down my money. I'm not all that into D-STAR. It's more complicated than it needs to be. But it really is the most widespread ham digital mode right now.

I don't really much want to start building up Motorola gear. RT Systems gets $50 for software and a cable, which is chump change compared to Motorola. Most of the more current RSS and CPS seats are $250 per license, so you have to stick with one model otherwise just programming radios gets out of hand.
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Old 11-18-2013, 12:55 PM
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what's the benefit of going digital- means we could text each other, right? And built-in APRS? that FTM-400 sure looks pretty, but wow, $700?

Not the most positive review http://hamgear.wordpress.com/2013/09...esu-ftm-400dr/
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Old 11-18-2013, 01:40 PM
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At least one of those points is wrong. The FTM-400 does support the same type of cross band repeating as any other Yaesu radio, for one. Not sure what to say about the others, they are generally the same (for good or worse) as the FTM-350 was. Banks in memory are one thing I really wish the FTM-350 had for sure.

Digital is, well, digital. Is it necessary for amateur radio? No probably not, no more so than in public service and business radios. There is plenty of debate on the merits in all services, not just ham. Firefighters generally hate digital radios. Being able to use voice and data simultaneously is one of the main reasons. You can do that with APRS but it takes two channels, either two radios or a true dual bander that can TX on both channels semi-intelligently (e.g. do APRS TX on the secondary channel while you use the PTT on the mic on the main channel).

D-STAR and Yaesu's digital send along GPS and call sign data with each voice TX, so you can see a location each time other hams talk. APRS is a set beacon rate, so you might go minutes between position updates, depending on set beacon rate and packet collisions in the network. For trail work at slow speed this isn't bad but in a tactical situation (like race support or emcomm), knowing exact locations for everyone helps directors know who is close or not to an incident. The Yaesu system also has a group thing where all the members of your group show up in a list with updated positions periodically even if they are not transmitting. The radios essentially query each other to keep the table up to date.

When in range digital voice is like the step up from AM to FM in analog. There is zero hiss or background noise but remains within the same existing channel bandwidth. In full digital voice the Yaesu system uses 12.5KHz of bandwidth, which will sound quite high fidelity (although with no GPS data, just your call sign in the header). In simultaneous voice & data each stream gets 6.25KHz of bandwidth to remain within a standard VHF channel. Most commercial radios have gone to 6.25KHz channels for voice only, which you may have heard referred to as narrow bandwidth. The FCC requires it of them, we hams are allowed to set whatever we want. But since repeater pairs are usually completely assigned, freeing up some spectrum by narrowing channels would be handy on 2m.

The reason I have not pulled the trigger is that the FTM-400 display is N-I-C-E. Touch screen, deep color. It'll be sweet to operate. Yaesu kind of dropped the ball on a handful of technical features, so the TM-D710 still has some advantages. I'm stuck with indecision. If it was a question of the FTM-350 vs. TM-D710, I'd be getting the Kenwood at this point. But I can not emphasize how cool that interface is on the new FTM-400. It makes everything else look like 1980s CBs.

The TM-D710 goes a step further than Yaesu and provides a true, full TNC so you can do true packet and voice at the same time (with a computer plugged into the radio). The FTM-350 and FTM-400 can only receive APRS data on the serial port so any outgoing APRS data is generated in the radio (messages, beacons). You can disable the internal APRS & GPS and use an external TNC on the port, but that is the same case with any FM mobile, so the built-in stuff is of no use and expensive.

Price floats around $700 for a FTM-400. But this includes GPS built-in to the controller. A TM-D710 sits at around $550 but the closest configuration includes a Greenlight Labs GPS-710 that mounts on the control head, which is another $125. So the cost ends up $20 to $40 lower. The FTM-400 is a bit cheaper than the FTM-350 + FGPS-1 was before it. The radio itself was about $650 back when they were offering it and the GPS module was about $75 as I recall.
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Old 11-18-2013, 02:15 PM
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Quote:
Originally Posted by DaveInDenver View Post

D-STAR and Yaesu's digital send along GPS and call sign data with each voice TX, so you can see a location each time other hams talk. APRS is a set beacon rate, so you might go minutes between position updates, depending on set beacon rate and packet collisions in the network. For trail work at slow speed this isn't bad but in a tactical situation (like race support or emcomm), knowing exact locations for everyone helps directors know who is close or not to an incident. The Yaesu system also has a group thing where all the members of your group show up in a list with updated positions periodically even if they are not transmitting. The radios essentially query each other to keep the table up to date.
so how would this work- would I see you in a little map on the same display? or would i have to have a separate screen or laptop to display that info? A little GPS of the trail with bouncing dots sounds beyond awesome...

And what do you mean about "just your callsign in the header.." are you saying when I transmit digitally you'd see my callsign on your radio? So kinda like caller ID? wow.
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Old 11-18-2013, 02:27 PM
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The other station's location is just shown relative to yours. IOW, a compass heading. None of these radios have maps like you're used to with GPS devices.

You can send a stream of GPS data out of the serial ports which is then potentially displayed on an external device (computer, tablet, etc.). I use a Garmin Nuvi 350 with my FTM-350 and all the APRS beacons show as waypoints on the map and in the list of navigable places, like they are McDonald's or something. If I punch another station as a waypoint the Nuvi calculates the way to get there on existing roads from it's base map. Depending on my zoom level any station beacons I hear also show up as dots on the map. That is the quasi-tactical nature of it.

With digital radios the voice and data is converged onto one channel where as with APRS it's a whole second system with different repeaters, different paths. That is fine but it's nice to know that your digital information is making it or not by knowing if you're in range via voice.

However, when you chose not to do voice and data with the FTM-400, IOW the total bandwidth is dedicated to voice, it still embeds your call sign at the beginning of the voice stream. I think this is the same case with ICOM digital radios, it shoves the call sign onto the voice-only stream. This is partially necessary with these protocols, since your call sign substitutes for the radio ID. Commercial digital systems require all the radios to have identifiers registered to them, but ham being decentralized does it differently. As long as you have a call sign and not nulls in the stream you get included in the registry.

Then it displays on other people's radios, although that's really not the whole of it. The reason they do this is when you connect to a digital repeater adding that call sign data will change your status in the linked (over the Internet mostly) gateway databases and if someone was watching for you to key up it would notify them and they could call you. It's like combining IRLP and APRS functions in a sense, but automagically.
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Old 11-18-2013, 03:28 PM
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That's pretty cool, thanks Dave. Even without the digital repeaters the "caller ID" feature I could see as useful, doesn't replace the need to actually ID your station obviously, but a nice way to reinforce who you're speaking with, and what their callsign is next time you want to call them. Plus, if someone at random were to just key up and start talking, you'd know exactly who that was (presuming you're both on digital).

I agree that screen does look pretty nifty, where would it fit though?
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Old 01-11-2014, 07:09 AM
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Did some horsetrading and rearranging in the shack, probably not the end of it either...

Added a Vertex Standard VXD-720 to the quiver and have started to doing amateur DMR. There is a fairly active local DMR-MARC repeater here in Ft. Collins and talk groups regionally, nationally and worldwide.

So far it's been a bit of learning curve but super interesting!

It also seems the first Yaesu SystemFusion repeater is on the air out in SLC, UT. K7JL has supposedly listed in Repeater Book but I haven't been able to get much more information on it. I haven't made any digital contacts with the FTM-400 yet, although it has worked fine so far for analog FM and APRS as well as doing GPS tracks. There is a growing list of bugs so I hope Yaesu does a firmware revision soon. There is no software to program it yet available commercially although I'm working on a way to edit the memory file on an SD card and then just upload it to the radio. Having a SD card slot is pretty handy.

http://www.repeaterbook.com/repeater....YJEGsX3t.dpbs
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Last edited by DaveInDenver; 01-11-2014 at 07:56 AM.
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Old 01-11-2014, 06:38 PM
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Did you wind up getting the FTM-400? How much bigger is that display vs the 350?
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