TDMA is time-division multiple access. It just means dividing the channel into time-slots, where each is some number of milliseconds. So, say we had two slots, each 20 ms long. We could receive for 20 ms, and then re-transmit what we received in the next 20 ms. No duplexers, no front-end overload, just one frequency. Works really well with digital modems and voice codecs.

Actually the nature of the content does have relevance. It absolutely must not be commercial. Now, give me a way to regulate that when I can't break the encryption.

And if you are about to tell me that you should be allowed to do commercial stuff on Amateur Radio, you won't gain any sympathy. That's what your cell phone and a dozen other radio services are for. This was never meant for you to check your gmail, etc.

I think you should assume that your desires were simply incompatible with the service, and that both you and the hams are better off that you're not participating.

If we put in every feature, we'd never get done. Maybe we'll have a 0-to-SHF radio eventually.

I think Javier Serrano at CERN wants to fund improvements in Kicad and gEDA. I don't know enough about them myself. Chris has his favorite PCB program and I didn't force him to use something else.

But you think that's bad? The gate-array has a proprietary bitstream. You need a zero-cost but proprietary program to make it. That's the one that really irks me. We hope to work on that issue eventually.

Actually it makes a good TDMA repeater. That means that it can receive and transmit on the same frequency, in different time slots. And it can carry full-duplex that way too.

It won't cross-band on its own. The I/Q transceiver chip won't transmit and receive simultaneously, and there's only one VFO.

If everything goes right, we will crowdfund an assembly run in a few months. But it's got to be working completely first and through a short manufacturing run. We won't crowdfund and then make you wait while we design and debug it, as some other projects have.

Very nice project.

There are healthy projects like OpenHPSDR that incorporate all of those things you don't like. Our radio does for VHF/UHF what OpenHPSDR does for HF.

We're trying to create the platform that can host a decade of software innovation. Thus, we do pay the cost of being on the leading edge. There will definitely be cheaper radios.

We're not selling kits. Either working PCBs, or complete radios. The hardware isn't under an Open Hardware license, although it's close.

The filter board slots are in the slides. Only one of the filter boards is shown. That one is meant to get spurious 60 dB down, but we've not tested it yet.

We have all of the right test equipment. Our main spectrum analyzers are Rohde and Schwarz FSIQ's, we have a high-end Agilent frequency generator, an HP Vector Network Analyzer with S-parameter test set, a GPS disciplined oscillator for the house frequency standard, a Faraday cage and an RF anechoic chamber, a lot of surface-mount assembly equipment, etc. I bought it all for cents on the dollar from companies like Nokia and Motorola that were shutting down R&D, the U.S. Government, etc.

By using gate-arrays, we get around some of the problems of unobtainable chips. We can move our design into different chips.

This particular design has an I/Q transceiver chip, and that's the only non-general-purpose chip. There are other IQ transceiver chips to which we could port our design.

Is there some standard way to manage timing? Does the weekend hacker need to deal with signal/buffer latency from the DAC/ADC or somehow manage timecode synchronization?

The DAC and ADC are clocked by the master 10 MHz oscillator, and there's a gate-array that you can program all sorts of hardware timing into. But if you are actually dealing with radar I would expect that you've already joined this mailing list.

If you work for a government and pay me, I'll be happy to answer that question. :-)

Everything is shared with the Amateur community, but we have some terms that protect our land-mobile market.

The software is Open Source, but the hardware is going to be slightly less than Open Hardware, and we will be careful not to mismarket it.

It's going to start out as a $500 SDR with not enough software, and you get to write it. That is with U.S. manufacture and U.S. parts sourcing.

And sorry, I don't know about the HackRF apps.

Michael's a good guy, but HackRF One is not a communications transceiver. He made it for hacking RFID. The receiver isn't that good and the transmitter is not FCC legal when amplified.

We're not giving them everything they need to clone the device. It's Open Source software and respects your freedom, but the hardware is under a bit less than Open Hardware licensing. None of the terms effect Amateur Radio, but they do protect our land-mobile market, which is where we expect most of the money to come from.

Actually, I led the fight to continue to disallow encryption on the Amateur bands just last year. I evangelized a lot of people to comment in opposition, and even dragged a reluctant ARRL into commenting when their original intent was not to do so. You'll notice that I am cited in the FCC ruling. It was only proposed to allow it for emergency communications, anyway.

You already have many different radio services where encryption is allowed. The shared, self-regulating nature of Amateur Radio makes encryption a disaster, as does the international nature. You can't self-regulate when you can't understand their communications. Nobody wants to see dxpeditions and HF communicators in general treated as spies by various nations, more than they already are.

We're perfectly happy with how useful Amateur Radio is, and it is not denial. Use the Internet and other services when you need encryption.