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Home ATS 1 Homebrew Kit ATS 1 20m SSB CW Transceiver Construction: An Introduction - ATS 1 20m SSB CW Transceiver Construction: VFO & Band

ATS 1 20m SSB CW Transceiver Construction: An Introduction - ATS 1 20m SSB CW Transceiver Construction: VFO & Band

ATS1 Project
Article Index
ATS 1 20m SSB CW Transceiver Construction: An Introduction
VFO and Band Operation
Notes - Before You Begin
Assembling the PCB
All Pages
Page 2 of 4
 
About VFO
For 20 meter band a Variactor tuned VFO with a range of 5 to 5.35 MHz is used.

By simply tuning the receiver band pass filter, transmit band pass filter for 3.5 to 4 MHz and assembling the harmonic filter at the output of power stage for 80 meter band, ATS-1 can be made for 80 meter operation without any other change. The VFO will however tune the other way round.

For use on 40 meter with 9 MHz IF frequency, the VFO will have to tune from 1.9 to 2 MHz to cover the 7 to 7.1 MHz range, the RX and TX band pass filter and the harmonic filter at the output of the power stage will have to be made for 40 meter operation. The VFO will tune the other way round in this case also.

15 and 10 meter: With 9MHz IF this ATS-1 can not be directly used for 15 or higher band because it will require a higher frequency VFO which may not be stable. If you can make a stable VFO from 12 to 12.5 MHz (for 15 meter operation) or 19 to 20 MHz (for 10 meter operation) then you can make ATSI for 15 or 10 meter operation. However a premixed VFO isrecommended for these bands. It will require addition xtal oscillator, balanced mixer and a suitable band pass filter for the premixed VFO output. There is no provision for these additional stages on the PCB. But because of improving propagation condition on the higher bands as the sunspots climb the next solar cycle; we are soon going to offer an add-on board for premixed VFO. The board will fix vertically near the VFO and will have all the necessary stages.

The ready made coils available as part of this kit are for 20 meter operation with 9 MHz I.F. The 9 MHz IF coils can however be tuned for 10.7 MHz I.F. by decreasing the value of the tuning capacitors. Therefore a 10.7 MHz SSB filters can also be used without much change.


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Newsflash

Space shuttle Atlantis lifted off from Kennedy Space Center, Florida, at 2:28 p.m. EST Monday, beginning STS-129, the 31st shuttle flight to the International Space Station.

Expedition 21 Commander Frank De Winne, ON1DWN and Flight Engineers Robert Thirsk, VA3CSA, Roman Romanenko, Nicole Stott, KE5GJN, Maxim Suraev and Jeffrey Williams, KD5TVQ, are making final preparations for Atlantis’s arrival, set for Wednesday.

The STS-129 mission will focus on storing spare hardware on the exterior of the station. The 11-day flight will include three spacewalks and the installation of two platforms to the station’s truss, or backbone. The platforms will hold spare parts to sustain station operations after the shuttles are retired. This equipment is large and can only be transported using the unique capability of the shuttle.