Posts by DO1OHB

    Hello Luico, congratulation, great HW for below 60€ (what I have seen on China Ali-Ex...).
    I also have bought 2 Nano VNA because I started with the QO-100 project and require something to measure in the range of 2,5GHz.
    I have the v2 since 1,5 month and already outdated. The v2.2 seams to be more solid with the N connector and solid cover, cable, box and calibration set and that for the same price.....

    Did it work with the Nano-Saver as well?

    73, Oliver

    Hi Holger, nice litte Pre-AMP.

    Interesting to see that you achieve with 15dBm input to the SG-Lab PA (v3) 43dBm output. So the 16dBm are nearly achieved and the full potential of the PA could be used.

    I will still use my AD CN0417 as it is smaller, direct match with the Pluto (designed for incl. Pand path filter) and have the right power for the SD-Lab PA V3.You found another interesting solution....

    Hi Trevor, as Wilhelm said,

    please measure (scope) the signal behind the C123. C124 is not required in that layout.
    I use a GPSDO with 3.3V signal and had a 3dBm attenuator in the path to ensure 1,8V at the chip input.

    But in the first step I would remove the ground mod. As the Pluto act 'normally' (SW side) even when the TXCO or GPSDO signal is missing (just no signal receive). If my GPSDO is off the SDR console work like normal (sure without any RX signal...). So without TXCO I would expect the same... for me I would start with the USB/SW analysis.
    And two change at the same time could cause several issues. Good luck!!

    73, Oliver

    G8AWB hallo, if you are still interested in my SG-Lab PA V2 contact me on my Callsign @DARC.

    oe3cbs hallo, it is a commercial WIFI Antenna from WIMO with integrated multiple patched (guess 2 double-fields) model PA-13R-20.

    It have 20dBi and is 33x33x9cm. For me it is ideal as it is very small and easy to handle. No problem to reach the satellite ;-) . Advantage, no adjustment needed/possible and disadvantage, just a transmit antenna. So I work via WebSDR and this solution.

    vy 73, Oliver

    DK8KW , Geri, since Wednesday my QO set up is preliminary final ;-) . And you was right, I started the test with a 6dBm attenuator and end up just with a direct connection from the pre-amp to the SG-lab Pa V3.
    I measured with the RF8000, a cheap Chinese power-meter, the input on the Pa and was surprised that I reached 40mW / 16dBm at 86% gain level (SDR Console) without any prior reduction. First QSO run very well.

    Interesting wise I used just 33x33cm Patch-Antenna 9cm high which is very easy to handle.

    So next step is the integration of the RX/TX antenna in one solution.(Patch-antenna and LNB)

    If anyone is interested in a nearly new SG-lab PA V2 please let me know.

    Vy 73 Oliver, DO1OHB

    Hello Holger,

    yes I also had my doubts but it with a simple 100W big old soldering iron (all ESD grounded) it was easier then expected. But the TCXO is relative large and had space around and the TCXO would then be defect I guess.

    Did you use also the 8mA set-up from Leo Bodnars GPSDO and 3dBm?
    No really sure what that 8mA stand for, as the voltage should always be 3,3Vpp on a 50Ohm output...?

    Vy 73, Oliver

    DK8KW , DD1US, team that is really helpful and I will change my set-up accordingly. That make me confident to drive the PA within the limits and to save an attenuator ;-) .

    This attenuator I will use for the GPSDO-Leo Bodnar to the Pluto. Yesterday I had a run and de-solder the original Pluto TCXO and exchange it with an external SMA jacked. I got also the very good hint to solder C124, but after search and find the place I was surprised. Even with glasses and 2,5 Led-lens I was just able to see the place for C124. At least for me there is no chance to solder a capacitor that is below 1mm. I wonder who could do it and how ;-) . Bottom line the GPSDO is now attached via a 3dBm attenuator to the Pluto and working fine.

    Thank you, 73, Oliver

    DK8KW, good point.

    I will take it in account in case I need additional power. Actually I guess the reduced power set-up will be suitable.
    And I know myself setting a Driver to 50% will be forgotten and 100% will be the standard ;-) . But as you said, even in that case the PA will not be at risk, just at the border. I can also confirm that the PA is not running hot just warm, I have a 190x200x12mm massive alu-block in a Alu-Wifi-Outdoor housing. With the PA its just 31mm and fit in the upper side of the housing. So all in one and easy to carry also for portable / Mobil-home set up.

    Vy 73, Oliver

    DD8PL , got my new SG-lab PA V3 yesterday. From the housing you can not see any differences, inside you will not find the 3 bridges for the PTT selection any longer but the new Vox and Pre-Amp. I am starting with the tests, so far it looks very promising.

    I drive the PA with the Pluto, Pre-Amp (CN0417) and 6dBm attenuator at a level of about 14dBm, input should typically be 40mW or 16dBm. I measure now a forward Voltage of 3,1V (from 3,5V at 20Watt).
    Further tests are ongoing. This new PA will reduce my effort significantly (can remove the EP AB003). ;-)

    73, Oliver

    I think the CN0417 is rated 1 watt so should be good for driving the SG Lab PA, so I did Pluto=>SPF5189 Amplifier=> 3dB attenuator=> CN0417=>SG-Lab PA . This would need less space than using the EP-AB003. I think the PA output is about 17W but can't measure accurately, but is enough for me.

    @G4MBQ , the CN0417 get 0dBm from the Pluto and increase it to around 20dBm which is 100mW not 1 Watt. As this device is powered by a standard USB port the entire DC power consumption shout be max 2,5 W on 500mA . So you can drive with the CN0417 direct the new SG lab PA version 3 as this new PA require 40mW (only an attenuator needed). For the version 2 device of the SG-lab PA you need an addition PRE-PA (I took the EP-AB003) to bring it to 500mW. The EP-AB003 is too strong for that job but worked perfect. Other Pre-PAs can do it maybe more efficient and are smaller and cheaper.

    'Specification RF Amplifier 2400Mhz Analog CN0417

    Frequency range: 2400 - 2500 MHz

    Maximum gain: +21dB

    Impedance: 50 Ohms

    Max supply voltage: 5V / 370mA

    With circuit: ADL5606 and LTM8045

    Insertion loss: 0.4dB @ 2000 MHz

    Bottom line, I guess getting 1Watt output instead 100mW will stress the CN0417 too much. It runs hot even with 0,1W.

    73, Oliver

    Hi Andreas,

    this is a great solution as my CN0417 was the 'hottest' device in the set-up.

    Especially the TX chip on the backside even when cooled with a little Raspberry-Alu-block.

    I guess I will follow your solution.

    Thank you!!

    73, Oliver

    Hello Matthias,

    I will use the Leo Bodnar single GPSDO as well. How do you connect it to the Pluto.
    Actually the most reasonable hints are:

    a) install a 18-27pF Capacitor (C124 , not used in unmodified Pluto)

    b) 3dBm SMD attenuator in the line to the Pluto (removed TCXO)

    How did you do it in practice?

    73, Oliver

    PC5E , the 12V from the car battery is a good argument, when I will be on tour I will use the 220V from my mobile-home ;-) . So yes, requirements are key and could be very different.

    Regarding the TCXO-Mod, I bought a lamp with 90leds and a 2,5x lens. Even then it would be a tough challenge. I installed the TX-Mod on the Pre-PA (EP-AB003 WIFI), just a little bridge between two chip contacts. It worked but I realize that I get older ;-).

    I saw some Plutos with TCXO mod on ebay but relative expensive so I decide to take a risk and challenge.

    Hi Robert,

    during my test I had it some times. I remove the power from Pluto (in my case USB), shut down the SDR-Console, restart the PC, started the SDR-Console, ensured the bandwidth was in TX range during the Pluto selection (USB) and it worked again.

    Not sure what the reason issued the problem but it worked again.

    73, Oliver

    The best 13cm bandpasses for hamradio (as far as know) are the interdigital filters made by DK2DB (check his shop)

    Wow that DK2DB-solution is rock solid and the measurements are impressive too.

    Out of the information above you strongly recommend a band path also between SDR and the CN0417 (first pre-amp). Got it. Thx.

    73, Oliver

    Hello Robert,

    your set-up plan looks nice. I have basically have/will have the same, so allow me some comments:

    1. RF band pass filter is always a good item but the CN0417 have one inside so it would be better to have a band-pass behind the last PA (but then you need a stronger one) - I have the same point and not sure how to fix.

    2. Power Management. The PA (with the highest power consumption) require 24V-28V. So my idea was the other way around. Meanwell 24V-90 Watt external Power supply (MW GST90A24) with two DC-DC buck converter (DEBO DCDC 25W) . One for 5V (as they are adjustable I go to 6,7V and then on a 5V voltage regulator (5A) LM 1084 IT5,0 to be sure that the DC-DC have 100% the right voltage and not higher voltage on the start). The second DC-DC for the BIAS 12/14/18V as required. Actually I have another Pre-PA EP-AB003 for 12V - will not need it with the new SG-PA V3. The DC-DC converter have a low load guess 1A for 5V and 0,5 A for 12V, so they stay cool.

    3. I guess you will need a frequency-stabilization for the Pluto (either TXCO exchange inside the Pluto) or external GPSDO. I will go with the GPSDO (another 5V for the DC-DC). This stable frequency could be used also for the LNB. Actually I am looking how to bring this frequency to the LNB cable (one cable solution like AMSAT-downconverter).

    4. The new SG-Lab PA V3 require only 40mW input (max 100mW) so you need an attenuator between CN0417 and PA (guess -6dB). I will get the PA in the next weeks and start with 6dBm, 3-5dBm for maximum output. As the PA have enough power (15W), also with 24V, it will not be an issue.

    That are my ideas around your question.

    73, Oliver

    PC5E, Robert, I guess I will start with a 6dBm attenuator as the power is much as sufficient even with 24V (that is the voltage I use). Then I am on the safe side, 2dBm more or less will not make a huge different (in that range) but could set the PA at risk. I guess with 40mW input you need to be carefull.......

    73, Oliver