F8VOL's QRP Constructions
QRP Kits
I've built the last 5 years
"Toucan"
40M CW Tranceiver
Designed by F6BQU
Schematic
The power is slightly more than 2,5 Watts. The Q1 transistor mutes the receiver to the right level during transmission. A simple AGC function is done by a LED diode.Simple and effective solution ! I like it!
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I did some slight modifications to the band pass filter. I also added an S-meter. |
"TenTec 1330"
30M CW Tranceiver.
Rugged case..
Tranceiver Block Diagram
The vfo and receive mixer compo design ensures pretty wide coverage and great sensivity
The 10mf cap solderd in place
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The 10K variable resistor for the VFO was causing frequency instability while tuning. So I added a 10mF capacitor between the middle pin of the pot and the earth to solve the problem. -Rig works great, and puts out approx 4 watts on 13,8V. -All the components are of a good quality. -I have made several contacts with it. -For the price, is a very good option. |
"EGV-40 CW"
40M CW Tranceiver
EA3GCY Kits
Schematic
I replaced the PA with a Mitsubishi 2SC1969 transistor and the power is about 5 Watts.
Inside View |
Enclosure is made of PCB |
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This modification as proposed by EA3GCY is mandatory, otherwise the side tone level is exessive!! |
"BCR"
5 Bands CW Tranceiver
QRPproject Kit
Schematic
Here in this kit, I added a 36 Volts zener diode between the collector of the final PA transistor and the earth to protect it against high SWR.
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I also added an oversize heat sink to the 2SC1969 transistor. The rig puts out more than 8 watts on 13,8 Volts |
Despite some difficulty in rf transformers winding the kit was an easy build, worked out immediatly and was fully operational after an easy alignement.
Features:
"CRK-10"
3 Watts CW Tranceiver
Designed by BD4RG
Ready to go.. |
The circuit |
The CRK-10 is a direct conversion receiver, with a two pole crystal as well as audio filters. Even though it uses the NE602 mixer, there is not noticable overloading from strong signals. Stable after a short warm up.You can not move from certain frequency ( xtal controlled ). There's no volume control. It hears about 400 Hz or more of band around the xtal's frequency (I have chosen 7030KHZ) but which sideband you are listening to can be easily found by pressing CFM key.A small microcontroller controls the keyer and auto-detects a keyer, bug, or straight key. You can adjust the speed using the keyer itself and store a CQ message with your call.
I like very much this little trx because:
The receiver is very quiet with no internal noise and is very sensitive. Listening to CW is a pleasure. It almost fits in a shirt pocket. .
"SoftRock RXTX Ensemble Transceiver "
1 W SDR Tranceiver
By Tony KB9YIG
Unboxing the soft rock.. |
Testing Rx part |
RF I/O and Switching Stage |
I built mine for the 20m/30m/40m bands.
This SDR transceiver differs from another sdr tranceiver kit I've built, because it has an other approach to handle the RF input and output paths along with the switching from receive to transmit, as can be seen above.
Also there is a galvanically isolated boundary between the digital and analog stages.(The ensemble has DC isolation between the Si570 / USB controller and the rest of the RxTx).
The computer interface and paddles are handled via USB port, so no serial connections are needed.
Homemade enclosure |
LPF |
This as an advanced level kit and many assebly precautions should be taken (ESD etc).
Soldering is challenging especially around the expensive Si570 and the tiny LFEA (aka FLEA) chip, used in the 3.3 voltage USB circuit.
Also winding transformers and inductors on small toroids is difficult too.
But everything went OK, thanks to the documentation of W5RVZ and the transceiver was operating from the very begging.
I use three different programs in a Win 7 machine.
HDSDR,
WSPR 2.11
and Rocky depending on the mode I wand to operate. (I never managed to operate the soft rock ensemble RX/TX with PowerSDR IQ). With the Rocky software and 1 watt I've made many QSO's, in CW and PSK31, as Rocky has a super PSK31 decoder built in, an iambic cw keyer and dual vfo operation as well.
Also I had once an SSB QSO on 20 meters with a ham from UK with 1W and HDSDR software.
I use an E-MU 0202 usb sound card (192kb) and an inexpensive (48 kb) usb sound card.
Finnaly the Soft Rock Ensemble RX/TX is an exellent QRP SDR tranceiver kit with an exellent receiver.
"FA-SDR TRX, "
160m to 10m SDR TRX
By DL2EWN
Unboxing the FA-SDR.. |
Preselector |
Easy to build kit , all SMD's are already soldered in place. Unfortunately the documentation is only for hams that can read Deutch.
I installed 1 Watt PA (The kit is designed to host max. 1 Watt PA)
The trx features:
An attenuator (to avoid overloading the receiver with too strong signals).
An adjustable bandpass filter / preselector.
A buffer amp (SGA5289) to ensure a 50Ohm match to the following stage. The amplifier is an MMIC with 13dB gain.
Contrary to softrock sdr, switching from receive to transmit is accomplished with miniature relays which are sensitive to vibration, shock or heat and some times they do not reset (I changed one of them twice).
A low-cost HF SDR transceiver that works great with HDSDR, Rocky and PE0FKO-USB-Driver.
"The Ultimate 3"
QRSS/WSPR kit
by QRP Labs
Kit arrival.. |
Beacon enlosure |
I installed all the PA transistors (BS170) and a LPF to run the beacon on 30M. Also a heatsink was added to PA's and to the IC oscillator.
To prevent frequency instabilities, before puting it on the air, I run it for a couple of hours in a dummy load. I run it ocassionaly in QRRS mode and not WSPR,that requires time presision, because the GPS module is not installed
A slight frequency drift after two hours "warm up" ..
"EK1A "
40-30-20 Meter CW
by YouKits
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An easy build kit RX covers 7-16Mhz, DDS controled VFO, Power output: 4-5W, Built in keyer. |