It's been a VERY busy 10 days for me with RXTXDX.com. Between online downconverter sales and a bulk offline order I've been modding and filling boxes to beat the band. I'm finally catching up and most remaining orders should be filled and in the mail by Thursday morning at the latest.
Going forward I should be able to ship on the day of your order or the following morning, USPS office hours permitting. No more waiting list.
PDF Tutorials and a video are coming later this week!
What's next? A few things that may be of interest to you:
Effective immediately you'll be able to order your CQMD with a 12V 1A wallwart style power supply instead of the 9v battery pigtail for an additional $5. I've had a few requests for this option and the power supplies arrived today. Just use the Downconverter-PS listing when purchasing. However – I've not received my European style outlet power supplies yet. I have a small quantity of the European style ordered, waiting on arrival. If there is enough demand for the European 2 round prong style supplies I'll get some more in. Email me or leave a comment below.
Adapters: I have F-type MALE to SMA FEMALE adapters for the antenna side of the CQMD ordered but they still haven't come in. Hopefully later this week I'll have them in the shop.
Filters. I've ordered a supply of different filters to use with the CQMD. 2.3GHz-2.9GHz, 2.4GHz-2.5GHz, 3.1GHz-4.9GHz and some that cover most of 5-6GHz. These filters will remove the out of band mixing products that are present and improve RX performance throughout it's covereage. Once the remaining filters arrive I'll develop boards to mount them on and rush them off for production.
The filters will also work great for RX and TX with your ADALM-PLUTO SDR, HackRF, BladeRF, USRP, (maybe even RaspberryPI) and other type of transmitting SDRs and transceivers to remove unwanted harmonics from your TX signal. Just don't run a high power amplifier through them. They're mostly rated for under a watt. I'm going to test the two filters that cover the 2.4GHz band with a 5 Watt PA to see how they stand up, but I'm not expecting much, maybe some smoke!
I've been looking into LNA's that would cover the downconverter's range for the RTLSDR and I think there is one already on the market that may work for us here, at least partly. The LNA chip PSA-5043+ on Adam – 9A4QV's LNA4ALL should cover up to 4GHz, but I haven't asked him if Chip/board design will work that high without too much antenuation. There are some measurments on his site linked above. I'll ask him and see what he thinks. Since we're not making military grade equipment here I think it may get by just fine at lower gain levels, but I'll post later or ask him to make a statement one way or another to that fact. There are also a few listed on ebay and elsewhere that claim to work up to 4-6GHz that are relatively cheap.
The BFP420 works up fairly high (25GHz) but is not as stable as an MMIC or newer designed LNA. Anyway, for now I've determined it's probably not in the cards for me to offer an LNA at this time. That may change in the future.
Something that may work well is yanking the PCB out of an old C-band LNB or similar and cutting the 3-6GHz LNA portion of the board off with a dremel. Wire that up with some SMA connectors and apply the appropriate power. That should provide some decent gain in the range of 20-30dB anyway. For that fact grab a cheap new C-Band LNB off ebay for around $10-$20 USD and canibalize that.
*** A little something different – A New Kit for the Microwave bands ***: I have some prototype boards waiting to be etched to make a Wideband FM 2.4GHz, 5GHz, 10GHz, & 24GHz interchangable transceiver. Using radar/motion sensors combined with one of these boards and your RTLSDR anyone will be able to talk, send data, or do other activities in the ISM portion of the aformentioned bands. Additionally Amateur Radio (Ham) operators will be able to modify their radar/motion sensor boards to work in the corresponding adjacent ham bands (or I may provide them ham ready for those providing a license). You'll be QRV and activate the microwave bands for a very reasonable price! I'm aiming to keep this kit under the $50 mark including all hardware except an RTLSDR. Hopefully my costs will stay low enough to make that happen. If you are interested in something like this in a kit or ready to operate form let me know in the comments below and I'll put some priority on it.
That's all for now, 73.