(Images from both vendors websites)
This radio set, the CS Series, is the follow on the earlier KN-Q7A radio kit. It is a SSB only rig.
The radio is sold as a kit from China (http://www.crkits.com/) with a US dealer in Idaho, QRVTronics (http://qrvtronics.com/). It will take some time to assemble, but all parts are thru-hole and the manual well written, laid out and illustrated. Nearly as good as the old Heathkit assembly manuals.
(see assembly manual http://www.crkits.com/csmanual.zip) This is a ziped manual. Unzip inside of it's own folder.
If you deal with Adam @ CRKits in China, you will likely have something of a wait for your shipment. Adam is a full-time worker with this kit as as a sideline.
Larry @ QRVtronics , based in Sugar City, ID, ships quickly and via USPS - as an Alaska resident, this is something near and dear to me - not getting gouged on shipping. Larry will also build and tune the rig for you at a very reasonable price point.
In an unusual move for small radio vendors in China, Adam has a full documentation set, to include a schematic, all IN ENGLISH, available on line ( see http://www.crkits.com/csmanual.zip) . This manual is a work from many hams in the QRP community and is well done. (Manual can be had in Spanish version as well)
The build manual is done in sections, with testing at each step. the IC have sockets.
The full documentation was also the reason I got off the fence and sent my boxtops off the Larry for the radio.
Here is where it gets interesting.
The CS series is the KN-Q7A with a full band coverage digital VFO. The CRKits version is a single band. You can pick 80, 40, 20, 17 or 15 meter bands.
Output on 80 and 40 meters is at least 10 watts, so this is - by Amateur Radio Service convention, not considered a "QRP" radio.
Output on 20 M is 5 Watts, on 17 M - 4 watts and on 15 M is is around 2 watts.
The QRVTronuics version of the kit is available as a dual band kit, pick any two.
Optional frequencies are:
Base Radio (40 Meters) plus 80 Meters.
Base Radio (80 Meters) plus 40 Meters
Base Radio (40 Meters) plus 20 Meters
Base Radio (20 Meters) plus 40 Meters
Base Radio (20 Meters) plus 15 Meters
After several experiments, Larry has found that if you want 40 and 20 Meters, it is best to build the 20 Meter and add 40 Meters filter kit
In kit form - you get a filter assembly board that allows use the second band.
Now, here the cool part -
The VFO is controlled by an Arduino microprocessor and the code in also posed to the CRKits site. A full VFO kit and software loader for the microprocessor can be had from either vendor. The Arduino is supported by the IDE environment and this software can be had on line for free - part of the Arduino community. A very open bunch.
The software sketch (processor code) is also found on line at the CR kits site for you to download. .
Larry has the dual band sketch (code) for the processor setup if you go with the dual band radio.
I'm working with Larry to get a copy of the sketch (Arduino code) to allow modification for RX of WWV at 10 and 15 Mhz) This will be posted to the QRVtronics site when completed.
Since the summer is a busy time for me, I ordered an assembled 20/40 meter rig as these are the best pick fro my area. For the L48. the 40/80 Meter might be a better pick for NVIS type communication paths.
This is a compact radio set that uses a speak/microphone. This radio, as do many of these kits, lacks an AGC loop, so headphone use is not a good idea. This is where the speaker/mike shines. The only controls are volume, VFO and on/off.. On dual band units, there is a toggle switch for changing bands. No menus, no forest of buttons. This is a basic SSB radio.
BTW - the additional filter fits above the main board. The case, solid metal, has a slot to hold the boar
https://www.youtube.com/watch?v=yNpACphHCY0
Edward, KJ4FGI, hos posted a video of the KN-Q7A version of this radio in operation. The CS version is identical, other than the full range digital VFO.
See the QRVtronics website to see images of the large and small digital display options. Otherwise, the VFO frequency is displayed via a quirky dual color LED. There is a video on the CRKits webpage explaining how to 'read' the color changes. Clever, actually.
The radio is a common NE602/LM386 kind of setup. The final PA is a IRF-510, which is noted for being more tolerant of high SWR at the antenna. The radio also has a reverse polarity protection diode as well.
The vendor shows these specifications:
. Dimension: 153 mm x 97 mm x 40 mm, not including connectors and knobs
6.0 x 3.75 x 2.0 inches including feet
. Weight assembled: 12 oz, not including microphone The dual band version is slightly heavier.
. Power Supply: 12 to 13.8 V, 3 A
. Current consumption: 70 mA in RX and about 2 A in TX @ 13.8 V
. RF output: about 5-10 W PEP @ 13.8 V typical
. RF output for 15, 17 and 20 Meters will be between 1 and 5 watts typically
. Sandwich digital VFO integrated with the LED hole pre-drilled
. Innovative one LED frequency display
. Stable and accurate frequency like a crystal
. Both USB and LSB are be supported by changing BFO frequency in calibration mode
. Sensitivity: about 0.5 uV at 10 dB SNR
. UNBAL jumper added to intentionally break the balance of NE602 to allow more
convenient TX power peak alignment and antenna tuning
. Low dropout diode is used to allow a bit more battery life
. Final power amplifier changed to IRF510 and minor change in LPF circuit
. Speaker microphone added to the standard configuration
. IF filter: 6 pole crystal ladder filter + 1 pole post IF amplifier crystal filter
. IF bandwidth: about 2.0 KHz
. IF frequency: 8.467 MHz
. Connectors: Speaker, Microphone and Antenna
. Antenna Connector is: BNC type
Larry also offers a digital display mod for his kits at a small additional cost. I went with this as well.
My early bench testing showed that full band overage was as spec'd and power output specs were easily met on my rig.
NOTE - power output is input voltage dependent. On my 8xAA NiMH battery pack, power was 8 watts on 40M and just under 4 watts on 20M. On a fully charged AGM battery, full power was no problem.
Why would would readers here care?
This radio, and a small Near Vertical Incidental Skywave (NVIS) antenna should give you reliable comms on 80 or 40 meters, pretty much all day, within ~300 miles of your location. At least a General class Amateur Radio Service license is required to operate this legally. Coupled with low weight, simple controls and decent power on 80/40M (10 watts) this radio is in a niche by itself...
Total cost, with shipping and assembled for the dual band with digital display radio is under $300 right now.
My wife gets unhappy if I carry my KX2 outside to anything other than the RV, and I agree. This rig is solid, simple and low cost enough to to bush bash with at little risk.
Hope you found this of use.
CS series radio kit - low cost SSB portable xceiver
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