50 MHz RX by LY3LP
Mixer KE3IJ idea
http://sa555.blogspot.com/2009/08/6-m-rx.html

50,06 - 50,120 MHz RX by LY3LP
 
http://sa555.blogspot.com/2011/05/blog-post.html

50,060-50,1MHz RX IF 22,118 MHz by LY3LP
 
http://sa555.blogspot.com/2011/06/50mhz-rx-if-22118-mhz.html

50MHz - 28MHz RX Converter by DL5NEG
The concept of the RX converter is quite simple and nothing really new. The local oscillator is a standart colpitts crystal oscillator producing the 22MHz LO signal.
http://www.herbert-dingfelder.de/?page_id=186
 

50MHz Converter by ON6MU
Tune to the desired bandpass frequency (50Mc) with C9 until you have the best reception. Use C12 to calibrate the output frequency to your receiver.
http://users.belgacom.net/hamradio/schemas/50mc_converter_on6mu.htm
 

An SA-612 Six Metre Rx Converter by VK2FC
I built this receiving converter in December of 2018. The 50MHz RF & mixer stage is an SA612 integrated circuit followed by a 2N3904 post mixer amplifier at 28 MHz.
http://www.vk2fc.com/6m_sa_612_converter.php

An Ultra-Simple Receiver For 6 Meters by N1TEV
Here is a simple VHF receiver you can build without any special components or test equipment. This receiver uses superregeneration for high sensitivity and low parts count. It can receive both FM and AM modulated signals.
http://www.arrl.org/files/file/Technology/tis/info/pdf/9712039.pdf

ARRL Six Metre Rx Converter by VK2FC
I built this converter in 1986 as an adjunct to the 3 Watt transmitting converter also featured in an ARRL Handbook of that era.
http://www.vk2fc.com/arrl_6m_converter.php

Converter voor de 50MHz amateur band door PA5HE
Deze converter heb ik gebouwd voor iemand die wel een HF ontvanger heeft, maar zonder 6 meter amateurband.
http://www.hvde.nl/electronica/6mt_converter_nl.shtm
 

Glass six box by LY3LP
 
http://sa555.blogspot.com/2009/08/glass-six-box.html

Simple 50MHz receiver by LY3LP
G3XBM and N1TEV ideas.
http://sa555.blogspot.com/2009/07/simple-50mc-receiver.html
 

Simple 50,1 MHz converter with LA1185 by LY3LP
 
http://sa555.blogspot.com/2011/06/simple-501-mhz-converter-with-la1185.html

Six Meter Converter by WN5Y
From the article "Junk-Box Converters for 6 and 2 Meters", by Rod Kreuter, WA3ENK, QST, January 1997, Page 33.
http://www.pan-tex.net/usr/r/receivers/fr03001.htm

Six metres on your two metre receiver by VK3YE
This converter allows reception of six metre signals on a two metre receiver. It should therefore be useful for those with single or dual band sets that do not cover 50 MHz.
http://home.alphalink.com.au/~parkerp/projects/proj6mco.htm

Super Regenerative Receiver by JF1OZL
This is a super regenerative receiver. By the 455kHz IFT, it oscillates 455kHz. It is G2 tuned feedback oscillator. By this oscillation drain current becomes cut off situation on 455kHz.
https://www.emilio.com.mx/jf10zl/regen.htm

The 50MHz RX "MINIMALIST" by LY3LP
Fits like a tone control transmitter, frequency meter...
http://sa555.blogspot.com/2011/05/minimalist.html

Tune six metres on your two metre receiver by VK3YE
This converter allows reception of six metre signals on a two metre receiver. It should therefore be useful for those with single or dual band sets that do not cover 50 MHz.
http://www.alphalink.com.au/~parkerp/projects/proj6mco.htm

Ultra simple 50 MHz converter by LY3LP

http://sa555.blogspot.com/2009/08/ultra-simple-6m-converter.html