tag:blogger.com,1999:blog-11282959.post3582503477468373271..comments2022-12-04T21:32:30.043-05:00Comments on AA6E Station Log: Quick Look at FUNcube Dongle SDR RadioMartin AA6Ehttp://www.blogger.com/profile/14329680325036851280noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-11282959.post-73769510862763419702011-02-18T13:24:44.502-05:002011-02-18T13:24:44.502-05:00Sorry about the name! The history is this. It'...Sorry about the name! The history is this. It's no secret that we completely underestimated the level of demand for the FUNcube Dongle, and in the rush when trying to take this from a kitchen table project to a manufactured unit, the prospect of thinking up a better name disappeared off the radar. By the time we had any time to catch our breath, the horse had rather bolted, so we just left it as the FUNcube Dongle.<br /><br />You are right about preselectors, particularly at VHF. The FUNcube Dongle does have programmable filtering, but it's limited at VHF. Things improve significantly at UHF and above. We have some suggestions to alleviate this already docuented and we're working on others too.<br /><br />Regarding the versioning, you are right, the first couple of versions of firmware did not have a method to expicitly indicate the firmware level, although a smart programmer would be able to code someting up to probe the version. <br /><br />This was as a result of running out of time before Christmas when our first manufacturer pulled the rug from under our feet, rather dramatically telling us that they weren't up to the job the day after they were meant to deliver. I therefore spent Christmas making the first 100 myself, on the kitchen counter, but we did deliver our first batch as promised in December.<br /><br />This is a constantly evolving project. Firmware updates are frequently being supplied. I deliberately didn't provide AGC because I was concerned people would think the unit was insensitive. This could quite easily be implemented in firmware, however it would be based on the tuner's IF passband which is several MHz.<br /><br />I would dearly love to broaden the bandwidth, but key to this project's original concept was to provide a passband wide enough to receive a very few kHz wide BPSK telemetry downlink, and do it as cheaply as possible, and anything else was a bonus. <br /><br />The key to making this reasonably priced was to use mass market TV set top box tuner chips and audio codecs for the ADCs.<br /><br />Providing several MHz of bandwidth is expensive in ADC terms.<br /><br />The first pre production units only had 48kHz. It is possible that we may be able to squeeze out 192kHz and/or 24 bits, but I fear the unit will be panting quite a lot if it is even possible.<br /><br />The sensitivity of all units is measured to be within a dB of 12dB SINAD NBFM on 2m at 0.15uV. Of course if it's overloaded then the noise floor will rise and you'll see apparent insenstivity.<br /><br />Certainly I'd recommend using a USB extension cable with the FUNcube Dongle: if you've ever used a TV USB stick, the TV cable will innevitably cause some stress on the USB plug. I am sure though that the form factor has unwhitingly been one the reasons for it's popularity.<br /><br />Anyway, thanks for the feedback, I welcome it. <br /><br />73, Howard G6LVBUnknownhttps://www.blogger.com/profile/02976098854020309324noreply@blogger.com