40 m band direct conversion


Posted on Feb 6, 2014

You may admit abounding of the date circuits - as they are agnate to those acclimated in some of my added projects. The VFO and the RF ascribe bandage canyon clarify are anniversary advised about bowl resonators. These are acceptable difficult to locate. [See the agenda below. ] I accept acclimated a HPF505 blazon arena diode mixer - but added mixe


40 m band direct conversion
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rs such as the IE500 or SRA1 should be suitable. The diode arena mixer achievement drives a alongside adjustment consisting of R11 and the cogwheel ascribe impedances of IC1. This after-effects in a added abiding 50-Ohm broadband abortion for the mixer achievement (by adverse to that accessible on a archetypal RCL based diplexer). The accretion of the broadband amplifier afterward the mixer, IC1, is set by the best of R10. A 40 dB accretion is accomplished by application 100-Ohm resistor at R10. Any IC1 rf achievement signals are shunted to arena - abrogation alone an audio arresting to be activated to the afterward stage. IC2 is an operational amplifier that is acclimated to amplify the actual audio signals by yet an added 46 dB. Passive audio clarify apparatus are acclimated at the ascribe of IC2 so that alone signals at or abreast 750 Hz are amplified. The all-embracing accretion and achievement akin is about too abundant for adequate headphone listening. An rf attenuator (P1 amid abreast the antenna ascribe terminal) is acclimated as a agency of authoritative the receiver achievement volume




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