Flex 1500 Update 10/06/15
This little QRP fig is testing out to be a very capable transceiver. I have only made about a half dozen contacts with the radio on CW and SSB. However, I find it very sensitive and selective and great fun to operate. It is intended to be my front end for up conversion into microwaves but I see it can easily be used on any HF band.
The real joy is the PowerSDR computer display. On a $700 radio it is a killer feature. I can run 5 watts on my Ten-Tec Omni VII but I can’t enjoy all the display features of the PowerSDR software.
I have discovered what is an issue with some owners. It is the audio latency through the computer processing. A high speed multi core processor is a prerequisite for sure. I have a quad processor 3.4 MHz computer but I do experience the problem in CW when using the built in keyer with side tone and using the audio from the computer speakers. There is enough audio delay to mess up the brain / hand timing.
I didn’t discover this latency at first as I began using the audio from the “Phones” jack on the front of the radio case. There are no delay issues there. When I started using the internal AC1 computer audio, I see where the fuss is coming from. It is only noticed with the keyer side tone.
I personally do not find it a serious issue to use the phones jack for CW audio. I have a powered set of computer speakers plugged into the jack. Headphones are a usual CW operators friend and can be used here. There is some computer sound processing that may be missing using the hardware speaker jack, but not noticeable when operating CW.
Another work around would be to use an external keyer with its own side tone. Either case the operator will have an extra but not unusual piece of hardware for CW operation.
Latency is a quirk of SDR and I don’t see a perfect fix because of the USB limitations. It’s not a bug but a limitation. A limitation easily overcome by getting CW audio from the radio hardware.