/hamradio/ - Electronics

>>200

Sounds like we need to standardize things.

What would it take to do that?

>>292

A cheap thing everyone likes and implements. It's not happening.

Hams are now using D-Star, C4FM, freeDV, DMR/MotoTRBO nad APCO25 for digital voice. Even more datamodes in general exist, because people like making them and improving on them.

>>292

>>293

>>294

>D-Star, C4FM,

These aren't making much headway because you're locked in to Icom or Yaesu equipment, respectively. Theoretically another manufacturer could implement either protocol, but it's not happening because of licensing fees and whatnot.

>DMR/MotoTRBO nad APCO25

These have the same weakness as the first two - They rely on a proprietary AMBE/IMBE vocoder, which limits the ability to build a home-brew or software defined solution. They're also pretty much exclusive to commercial-grade LMR equipment, which even on the used market is far out of the price range of most hams. (A used & abused low-end commercial HT can run $400+, covers a single band, and ANY frequency or repeater information has to be programmed via proprietary software that the manufacturer may not be willing to sell to a radio amateur. It's worthless for amateur use without that software package).

> freeDV

This and Codec2, which it's based on, are very promising. Unfortunately, they're software-exclusive at the moment due to the algorithmic complexity, and Codec2 isn't yet mature enough for any manufacturer to spin custom silicon.

>>298

Hahaa! guess what? The rowtel folks are working on a "inline" box that includes codec2 and the modem used for HF freeDV. It is simply connected between the mic and the rig you get digital voice on HF!

So it is slowly happening. The rowtel folks are also dicking around with making a freeDV VHF demonstrator handheld. Software defined IF but traditional superhet before that.

The smart mic:

http://www.rowetel.com/blog/?p=3125

According to the blog, they are now shipping the smart mic. http://www.rowetel.com/blog/

The VHF radio is very strongly in the prototype stage:

http://www.rowetel.com/blog/?p=3856

http://www.rowetel.com/blog/?p=3884

http://www.rowetel.com/blog/?p=3971

So stuff is happening, and it's wonderful.

>>299

Interesting stuff. I'm personally most-interested in something with the theoretical capabilities of a modern P.25 system on VHF/UHF - Moderate bitrate audio (better than what you get with Codec2 on HF) plus either a second voice channel (potential for full-duplex between at least two users, more with an intelligent repeater) or data within a standard 12.5kHz channel.

>>300

One thing I'm sort of hoping to happen would be a codec2 retrofit of sorts for DMR or D-Star.

And yea, one should be able to run 2400baud or more easily on VHF and UHF with codec2. And the idea for fullduplex with two or more timeslots is actually very interesting. I would have just thought about the potential to make single channel repeaters with one timeslots for RX and the other for TX, like with TETRA DMO repeaters which function like that.

Most DMR repeaters around here have one of the two timelosts on DMARC or some other global talkgroup and the other on a local talkgroup pr repeater network.

So can I send CP to space?

>>300

>>302

Really, what we need for most amateur repeaters is something that can do 4 channels/bitstreams in a single 25 kHz wide channel. Right now the existing DMR networks are too limited IMHO because it's not feasible to do proper trunking in most locations.

>>306

That would be really cool, and might even be reasonably doable with current equipment.

I hate all this digital voice shit.

First off, its all proprietary, which is shit in and of itself, but that also puts its use in a legal grey area regarding part 97 use.

But most of all. I love ham radio because its such a simple hobby. You can make a perfectly good rig out of simple parts if you want to do cw or phone. I have nothing against digital shit in and of itself, but its adding a layer of complexity that I don't want to become the norm.

>>452

freeDV is 100% opensource from codec up :)

It uses codec2 at 1400baud.

I made an SSTV board if anyone wants to post SSTV. :^)

>>>/sstv/

>>203

The tapes aren't missing, they were recorded over most likely with Skylab data. Tapes are expensive, even for NASA (speaking of people that love proprietary formats…).