RF-UP-CONVERTERS

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If you want to receive short, medium and longwave radio signals with Software Defined Radio receivers like RTL-SDR dongle, Airspy, FunCube or with any other VHF/UHF receiver, then you need an Up-Converter which will convert low frequency band to somewhere in VHF range, where your receiver is able to receive. In other words, The up-converter shifts incoming radio signals with low radio frequencies from few kHz up to around 55 MHz into the tuner’s frequency range.

There are many up-converters available on the market today. One of the best and most popular is Ham it up converter from NooElec, and the up-converter developed by Makis, SV1AFN. Both of them are available in e-bay. They are powered through USB connector and equipped with SMA female connectors for RF input and RF output.
Both uses Mini-Circuits passive double-balanced diode mixers ADE-1.

1. Ham it up converter cost about 46 US $.
There are space left on the PCB for a noise source circuit as additional feature. Most of the components are already soldered but if you want to use the noise source, than you have to buy the rest of the SMD components required to complete it, which cost additional 15$ including shipping costs. Details of the noise source circuit with the project documentation are available in the internet.
Overall, Ham it Up converter with noise source circuit, cost me 61 $ including shipping costs. Noise source is very useful feature. For example, You can use the noise source with spectrum analyzer for characterizing or tuning filters, amplifiers, diplexers, antennas and so on…

2. Makis, SV1AFN Up-converter cost me 69 US $ including shipping costs.
This Up-converter has selectable Low noise preamplifier with 20 dB gain from two parallel Mini-Circuits Gali-74+ amplifiers. Declared noise figure of the amplifier is about 3 dB.
I am not suggest using the LNA for receiving VLF, LF and HF especially if you have a good antenna. The galactic noise (or noise temperature) is very high on frequencies bellow 30 MHz, so there is no need for Low Noise amplifier. But, in case of mobile receiving for example, with not optimal antenna, then LNA can be very much useful. You can switch it on and off with jumper on the board. Makis Up-Converter is designed with excellent filtration on the RF-input, RF-output and local crystal oscillator to reduce harmonics and interference.
It is very interesting that Makis has chosen the IF port of the mixer as input port, and RF port as output port. This is because it`s frequency response starts at DC, while the RF port starts at few hundred kHz. In that way, this up-converter has excellent results receiving VLF as well as HF and up to 55 MHz.

3. One of the best up-converters on the market is "Spyverter". More information about Spyverter you can find here.

You can see more information about up-converters in my video here.

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