Es'hail-2 transverter PA3FYM-approach

  • The attached photo also was posted on Twitter, but I thought it would be a nice one as first posting in this part of this forum!

    The transverter depicted below is designed as a real 'BUC' (block up converter) to be positioned near a (multiband) feed.

    It uses 432 (or another IF) MHz as IF and is built with 'standard' (Ebay-like) building blocks.

    In transmit mode the LO (ADF4351) produces 1968 MHz, is amplified (SPF5189z) and fed to a HMC213 mixer. The wanted RF sideband is filtered with a small ceramic 'WiFi like' block, amplified with a TQP3M9009 and after some

    damping fed to a surplus UMTS HPA.

    With some fiddling I managed to get >10W O/P on 2400 MHz.

    During reception the same LO produces 307.5 MHz, which is fed to a ADE-1 passive mixer. From a GPS-locked PLL LNB (e.g. Octagon 27 MHz, or Starcom 25 MHz) the first IF (739.5 MHz) is fed to the ADE-1 mixer.

    After the mixer IF port a J310 provides 'firm' 50 Ohm termination (and somewhat gain, but this is neglectable).

    On the photo the LNB GPS-reference is not showed, but it lies here in my work bench ; -) The reference is made from a surplus Jupiter GPS receiver (with 10 kHz reference), an

    ADF4001 (PLL) and a low noise VCO. All power supplies in the reference circuitry are heavily filtered ('capacitance multiplification' i.e. emitter followers with large capacitance from the basis to ground).

    Both ADF4351 and ADF4001 are programmed by one ATTiny13a.

    Yes, the setup is designed as 'simplex'.
    Power supply, IF (RX and TX) as well as 'PTT' is fed through one (thick) coax cable.

  • Experiment with GPS locked 27 MHz PLL LNB.
    Listening to the 11th harmonic (produced by a diode)
    of 953.6 MHz (generated by a GPS-locked signal generator).

    Click here for a short movie.

    Loopfilter was calculated with AdiSimPLL after I determined
    the Kv of my VCXO (4.36 kHz/V). Loopfilter BW = 300 Hz.

  • Dear PA3FYM

    1) What is the meaning of "The wanted RF sideband is filtered with a small ceramic 'WiFi like' block,"

    2) I want to homebrew the Transmitting section. But I want to use a 10m or 6m SSB Radio feeding to the Mixer. Is it possible?

    3) Please share at my email the schematic of Tx section.

    I am at ML88nk and I am able to receive QO-100 with Octagon Oslo to a RTLSDR with homebrew bias-tee.

    Please help me to brew the Tx section.

    73 VU2UUU

  • VU2UUU OK Kaustav, my idea was to use 432 MHz as IF frequency for both RX and TX. Of course you can use 28 or 50 MHz for TX-IF but I recommend to do that in an additional step (to avoid the LO signal and mirror image bleed through / will not be supressed enough).

    If you've only 28 or 50 MHz (SSB) you can think of the following (50 MHz example given):

    2400 - 50 = 2350 / 2 = 1175 MHz LO (from cheap ADF4351 board)

    So, the first conversion is 50 + 1175 = 1225 MHz , filter this (search for SAW filters for this frequency...) and feed this into another mixer with the same LO (1175 MHz) --> 1225 + 1175 = 2400 MHz.

    To clean up the resulting signal use cheap 'WiFi filters', designed for 2400 - 2500 MHz (e.g. I use CER0347B filters, but there are also from TDK (DEA252400BT-2030A1) but these are very small, only 2 x 2.5 mm !).

    As mixer I use a HMC213 (Ebay). ADF4351 signal is amplified with a SPF5189z board (also Ebay) and fed into the mixer LO-port. If you want to make the 'double conversion' approach you (probably) need another SPF5189z to feed the other HMC213 mixer. These cheap ADF4351 boards have two outputs, so that makes life easy!

    In the picture below I drew two SPF5189z's. Perhaps one is enough to feed two mixers. The ADF4351 boards I got from Ebay do not deliver +5 dBm (3.2 mW), but around 1.5 mW @1967.5 MHz. Using a SPF5189z board I got ~14 dBm, sufficient to LO the HMC213. But ... perhaps the SPF5189z board has more gain @1175 MHz, so one SPF5189z may be sufficient.

  • PA3FYM I am looking for good ADF4351 and ADF4001 breakout boards for some DIY projects and tests.

    There are many boards on the market / eBay. Can you give some recommendations to boards that works? (You never know when you buy from China / Ebay / Amazon what you get. Therefore I would like to get boards that have been used by other people before).

  • just a recommendation: when you receive your board BEFORE switching it on check immediately the stabilizer IC which should be a 3,3V one.

    last year I received 2 boards from 2 different shops which had a 5V IC...and the ADF4351 accepts a maximum of 3,6V!!!

  • PA3FYM , I’m enthausiasticly following René PE1CMO and you’re progress in building great stuff. But did you, or are you planning to publicise the source code for what you’ve build?

    I like to experiment myselves and want to build a dual (h/v) ref for RX, but aren’t that particular keen on writing software.

  • The software I wrote is beta and the 'early birds' (i.e. the ones who bought the initial prototype) know this (of course they are assisted when upgrades are issued).

    So, I prefer to wait a while.