[th0ma5]

There is a duality between affordable and performance. For example, the Hack RF is pretty great and has a large frequency range and wide bandwidth for a relatively small cost. But for HF transceiving you need probably need better filtering, which has to be specific to the band and mode, amplifiers both ways, although, with transmission you probably need several stages of amplifiers and filtering in each stage as well. So all of those things would be costly and depending on what you want to do it may be better to buy a regular radio.

[dsd]

I agree with the duality that you describe. Nevertheless, wouldn't the software part of an SDR reduce the need for expensive physical electronic components, while increasing ability? An amplifier seems to be the only additional expense (as you pointed out). It seems like the amplifier negates any cost benefit, yet utility remains superior if one doens't consider multiple components and building blocks a liability. It seems like there are expensive SDR transceivers (e.g. Flexradio) which utilize SDR technology to beat out the competition in specs and performance. To get on the air with a budget SDR, I haven't seen lots of demand for the idea. is the utility of a budget SDR just not better than your basic radio? It seems like it to me but where's the demand?

[th0ma5]

Yeah I think most big name radio producers see amateur sales as a secondary market. There are some hobby projects like the uBitx and the mcHF, and both are low power. The amplification and filtering are in opposition to dynamic range and total power output. For instance without filtering, a very strong signal will blow out the dynamic range and quieter signals will get lost. If you say were to build a ZetaSDR and plug it into a 192khz 24bit sound card, you would have excellent dynamic range for weak signals, but you'd still want to filter out local FM and AM stations.

I think as more SDR stuff gets reduced to single chips for commerical or military reasons, then perhaps the amateur equivalent will be viable... But filtering and amplification is still something that is difficult to miniaturize due to heat and wavelength.