Posts by DD4YR

Quote from DD0KP

DD4YR Robert can you share your solution here?

Of course. I oriented myself on an article on EngineerZone from Analog Devices. The source code for MATHLAB can be used 1:1. fits.

The measurement takes place in two steps. First, the forward current power is detected from the reflectometer on the frequency spectrum to be scanned. Then, you have to change the reflectometer, in the second step the reflected power is recorded, subtracted and plotted.

The only drawback: Yo can not measure in real time, since the measurement runs already takes 2 minutes ...

Items: https://ez.analog.com/universi…r-vector-network-analyser

btw: I use the 30 days trial version of MATHLAB ..

73´s de Robert

Quote from DD4YR

Anyway ...

Another idea: ADALM-PLUTO has integrated RX and TX, actually the ideal condition to use the device also with suitable software as a VSWR (reflection attenuation) measuring device via a directional coupler.

Has any of you aoready tried it? Any idea?

73´s de Robert

Task solved ..

I´ve now found a solution using MATHLAB to use ADALM-PLUTO as an SDR reflectometer. The result is amazingly good. Comparisons with purchased SHF filter and R&S measurement results are the same.

Here a plot of my 3-band helix feed, the 13cm part:

73´s de Robert

Anyway ...

Another idea: ADALM-PLUTO has integrated RX and TX, actually the ideal condition to use the device also with suitable software as a VSWR (reflection attenuation) measuring device via a directional coupler.

Has any of you aoready tried it? Any idea?

73´s de Robert

Quote from PY2SDR

For FT8, a delay of 1500 msec is not an issue.

As a matter of fact? The duration of a FT-8 TX pass is 13,48 sec !

Latency of Adalm-Pluto...

I think a not negligible problem is the digital processing times plus the latency over the satellite. Since come equal 1500 mS together (RX 600mS - Sat Latency 250mS - TX 600mS). Maybe a problem for FT8?

Quote from ik4idy

Unfortunately this device start from 325 Mhz...

Hi Alex, you can simply change the range from 70 MHz up to 6000 MHz

http://www.oe7wpa.com/index.php/my-projects/adalm-pluto-sdr

Power around 0 to 8 dBm is correct.

73´s de Robert

I´m afraid that adjusting the TX or RX by whistling (or CW) to the correct RX QRG will initially disturb a large part of the transponder operation ... I currently do not see much direct coupling of RX and TX when changing the frequency on the transponder ...

Quote from DD0KP

Today Simon has released the version 3.04 of SDR-Radio which includes the ADALM-Pluto.

... running ....

73´s de Robert

Interestingly, can you also record and display the characteristic Z impedance for the course of the VSWR? In the short test setup, there is no compulsion to 50 Ohm ...

I continue to use my old AO-40 equipment. At this time, it worked very well for 13cm RX, as well in TX during contests. For my 1,2m full parabolic dish I have ony 2.5 turns to illuminate the reflector accordingly... May be that the circluar radiation is not ideal and something squint at 2.5 turns, but on the RX side I had the best results at that time ...

I calculate the dimensions with this page: http://jcoppens.com/ant/helix/calc.en.php#out

... it works without a mebership, I´ve just tried and ordered ...

73´s de Robert

... I spent a lot of time with AO21 - RUDAK II .. was interesting time period ...

pe1chl

Hi, did you acutally measure the transmission power from your SG LAB transverter, or are the 2 Watt specifications from the manufacturer?

Zitat von g7iii

SG-LAB also have this:

http://www.sg-lab.com/TR2300/2300%20MHzTransverter_V1.4b.pdf

now it may only be 2W, but might be of use to some.

I have the same transverter. It should be noted that the output power of my device has only 1 Watt CW continuous carrier. Incidentally, I still see sidebands which require a filter after the transverter. If one calculates that even with 1 dB of attenuation only 0,75 Watts remain to drive a power amplifier ....

Here in JN57QS meanwhile also nothing to see. Remco, how strong do you see the Es'hail-1 11199.8H beacon? Here 26 dB SNR. (1,5m solid dish)

PA3FYM:

Remco, you're right, it may not be the perfect solution, but what can be fundamentally wrong?

The fact is, if I use crooked frequencies as the oscillator frequency then the converted signal is clean! In my case, the GPSO runs at 23.589743 MHz, I transpose the transponder band from 10.5 GHz to 1.3 GHz, and I could hear the beacon perfectly clean in CW!

When I fed exactly the 25 MHz at the first test I had exactly this jitter in the NF signal .....

I have no idea what else could be.

73s de Robert

Perfect!

Patrick, I had the same problem, using the GPSO from Leo Bodnar. I changed the GPSO frequenz a few Hertz then the effekt was solved.

I am not sure, but I believe that the divider ratio between PLL multiplication and fundamental frequency plays a certain role in this.

Just try it.

73s Robert

And be careful when transporting with FedEx is offered! It´s fast, but Fedex has its own customs clearance, which in addition to the sales tax due also takes 25 euros processing fee ...