EMRFD Message Archive 4765
Message Date From Subject 4765 2010-06-09 04:53:47 Fernando Krouwel Polyakov Mixers Sometimes I have seen Polyakov´s (RA3AAE) antiparallel diode mixer being used in some receivers (mainly in direct conversion european designs) and I found it very interesting, mainly because the LO operates at half input frequency, making easier to work the LO and (authors say) avoiding its leaking due to the high difference in frequency with respect to the input tuned circuit. Under this aspect, could be more convenient than diode double balanced mixers like SBL´s.
Examples of application are on the following links:
50 MHz DC Receiver (czech):
Elegant design 80 meter DC receiver (czech):
LA8AK´s DC receiver (dual band, 40 and 20 meter), bidirectional 14 to 144 MHz converter and other related experiments:
scroll down the index from the following page:
As we can see in the links, there are two types of mixers; the two diode type and the four diode type, with references that the four diode type works better...
Doug De Maw, W1FB (sk), in his book "QRP Design Notebook", page 111, fig. 5.3 makes brief references to this circuit but don´t tell us much and he doesn´t use the LO at half input frequency. In his example he uses a circuit that LA8AK in the above link says would not be the best way to implement it.
Has anybody here (the people with heavy laboratory capabilities) tested Polyakov´s circuit in the same manner as it was extensivelly done with double balanced mixers or even "H" mode mixers?
To have more predictable results, would be fine to find the original Polyakov´s writings about it (searching in the web, some materials are in a language that I can´t understand...), to find delails like impedance of input/output/local oscillator/isolation between ports, as well as best levels to work with it (input/LO) as we usually do with the more familiar type, the double balanced mixer.
Thanks for any information
Fernando - PY2ETT
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4895 2010-08-12 10:52:27 ehydra Re: Polyakov Mixers Fernando Krouwel schrieb:
> Elegant design 80 meter DC receiver (czech):Should be http://www.qsl.net/ok1ayu/projects/rx80.htm
Yes, would be an interesting topic. But I cannot give further info.