Es'hail-2 transverter PA3FYM-approach

BG0AUB Perfect. There are (more or less) two ways to program ADF4351 a) low noise mode, b) low spur mode and it also depends on desired 'channel spacing' and PFD-frequency. Try both (because there are differences in loopfilters on the boards).

Select 4/5 prescaler and check if purity improves. So R1 = 0x8029.

But, when I look at your spectrum pictures, it is not bad at all (for a cheap ADF4351 board) Hint: ADF4350 boards are cheaper ; -)

LO filter is not really necessary yet. I filter later.

From what I see on the analyzer: step 1 is finished.

Now step 2:

BG0AUB Measure output of 1965 MHz signal from ADF4351 board. It is specified that it should deliver +5 dBm , but I never measured that .. +2.5 - 3 dBm maximum here with the boards I used. So it is necessary to amplify it before it is injected in the HMC213a (Ebay) mixer board. I use a SPF5189z module (also Ebay). I got around +14 dBm @1967.5 MHz and inject this into the LO-port of HMC213a board. The HMC213a is a good mixer with very good LO-RF and LO-IF isolation.

Step 3 will follow after you measure around +14 dBm (25 mW) SPF5189z 1965 MHz output.

BG0AUB ADE-1 mixer for 739.5 MHz is ok. (I also use an ADE-1 for 739.5 --> 432 MHz)

For the ?-part, see picture below. It may be an idea to also have an attenuator between the LNB and ADE-1 because the gain of the LNB may be very high. But that is something to experiment with.

BG0AUB Good work! You got +14 dBm on 1960 MHz, perfect for the HMC213 mixer. Of course coaxial switch for IF RX-TX is also an option, especially for an experimental setup.

Concerning filtering ... perhaps a pipe cap filter is an option too, for the experimental setup. If you want details, let me know.

BG0AUB OK, try to experiment with different sizes and you will find one that is ok. Good work!

Now after filtering, amplify 2400 MHz signal (perhaps also with SPF5189z or other MMIC. TQP3M9009 works well, it has a lot of gain. After the pipe cap I got around 50 mW on 2400 MHz but needed to fiddle a little because the MMIC sometimes oscillated ...

Oh yes ... if you use double sided PCB, solder the connectors inside the pipecap compartment. See my picture.

do1ctl Wow! I never got more than 2 mW out of my ADF4351-boards. With a SPF5189z module I got around 25 mW @1968 MHz which I inject into the HMC213.

But your frequency (1175 MHz) is significantly lower.

When the 147 mW are 'real' mWatts then a resistor pi-attenuation of 7 - 8 dB would suffice (perhaps integrate it with SMD resistors on the HMC-213 (board) itself.

No, unfortunately it is not possible to let the ADF4351 generate two frequencies simultaneously.

Looks good! Which mixer did you use?

do1ctl Ah yes, that is of course also a possibility : -)