Quote from DF2IC

SV1BDS I'm using a design similar to yours, it is sold in DL by DH1ND (see his QRZ.com page)

Another design and an extensive discussion can be found at https://www.helitron.de/dj0abr/index.html "Helix Feed für es'hail-2", (unfortunately in german only but with many pictures )

My combination of Helix-feed and LNB works well, a little bit better than a POTY feed for RX and a little worse than separate TX and RX antennas. By "a little" I mean differences less than 3db in RX, I noticed practically no difference for TX. When transmitting in SSB I sometimes see a "ghost signal" on the waterfall but my receiver is never desensitized.

73 de Greg

Maybe the diference is due that my antenna has a plastic tube that has no effect at 2.4 but it may have significant loss at 10.5 GHz. Also the Amiko L108 may desensed from 2.4 GHz. I will make some lab tests to find the reason for both problems. Also I plan to try a dual feed antenna (patch & LNB). I will keep inform for results.

Hi,

Testing with an other Amiko L108 at LAB when I put in front of the LNB the plastic tube without the helix wire it has a large drop. Also when I put the 3 turns alone there is also a drop.

Quote from DD4YR

George, whit kind of plastic is the tube?

I do not know I have found these antennas at a radio park as surpluses. If there any way to find it please let me know.

Hi, my first QSO with PLUTO & GNURADIO is done !!!

Hi,

Tx simplified and Rx was added !!! My homebrew SDR tranceiver !!!\

upd = 2048 vs 2084 ...

Hi,

An idea I had is to use Pluto as full duplex portable transceiver for 2.4,5.6,10 GHz. For 10 Ghz LNB can be used for Rx and up conversion will be required for Tx. Typically a 6 band transceiver can be made for 70,144,432 MHz,1.2,2.4,5.6 GHz. Most equipment exists here and QO100 support will be one application. SDR console can be used for software.

Hi,

TNX Mathias, this is my POTY, it has good SWR. One eBay china corner N adapter is not good for 2.4 GHz.

Hi,

Preparing the portable version a bulding block for Rx is done. A HPF/LPF for 739/25 MHz, a bias tee for powering the LNB and a ADE25MH mixer is included.

Hi,

My POTY finished !!! SV1JCZ (THANKS Daniel !!!) provide me the 22 mm tube adapter that was essential. No signal drop during Tx was notished and receiving performance was as expected.

Hi,

A MAV11 was added to the 430 MHz signal as signal was poor after 60 m of 75 ohm cable. As not all of MAV11 gain was not needed a 470 ohm was biasing the MMIC instead of the 120 ohm.

Hi,

This RTL LINK has been modified for external 28.8 MHz reference. A GPSDO has driven a signal generator for producing 28.8 MHz. No noticable drift of beacon was noticed. Even the 2832 was a T version and not a T2 no SNR decrease was noticed.

PA3FYM The GPSDO has compared to cesium reference and when producing 10 GHz a drift of +-2 Hz was noticed. The TC was about 100-150.

Hi,

A SI5351 using a designed PCB is tested to produce the 28.800 for RTL. The result is that the received beacon is not exact on the frequency(180 Hz dif). The possible reason is that the produced signal is not 'exactly' 28.800 due to PLL step (but it was stable). Any similar experience ?

Hi,

A local oscilator for Rx & Tx @ portable version using ADF4350 and external 25 MHz reference. A PTT line (via a optocoupler) is available and a VHF / UHF switch is for IF selection.Frequencies produced are 2255.5 , 595 , 1969.5 , 309 MHz.

Quote from SV1BDS

Hi,

A SI5351 using a designed PCB is tested to produce the 28.800 for RTL. The result is that the received beacon is not exact on the frequency(180 Hz dif). The possible reason is that the produced signal is not 'exactly' 28.800 due to PLL step (but it was stable). Any similar experience ?

Hi, it seems that the problem is due to SDR Sharp. The SI produces the correct frequency !!!

Hi,

In order to compare GPSDO with Cesium as a reference the two 10 MHz signals is driven a SBL1 (Lo from Cesium & RF from GPSDO) and output (reminder IF is down to DC out) is feed to a scope at DC input. The 'fat' line is due to the 10 MHz leakage from both inputs and 20 MHz mixing signal. No noticable 'oscillation' of the wave is noticed.