thanks for the software
thanks for the software
The BU500 is nice, but it has (at least the 2 i bought) a problem powering up if the supply voltage is a rising at power up.
I solved this issue with a small relais which switches the voltage on to the BU500 with a small delay when the voltage of the psu is stable at 12V.
The amp inside the BU500 could generate about 2W without problem but the bandpass filter is designed for 500mW max. So be carefull.
It could be a good idea to remove this bandpass and use a good lowpass after the main amp.
Also i did not get the "programming software" with the BU500 to change the LO frequency, but it is preset for 430MHz and thats fine for me.
The other specs and measurements of the BU500 are all good to excellent.
Is the sat spinning in the moment?
The beacon signal level is periodically (ca 30sek) getting weaker and stronger again.
18:56 everything normal again...
For use on 2,4GHz maybe the anaren filters are better removed?
Usually they are specified for 2,17GHz
a mrf21030 amplifier is nice to start with. 11W should be sufficient on a 80cm dish.
In my nokia amp are also some of this 030 MRFs.
This mrf21120 amp module ist very similar to the three finals in my ericsson amp.
A few weeks ago i saw on eBay some guy (chinese?) selling those modules "cutted out" from such an amplifier.
vy73 de DB8TF
Here is my rx setup:
on the left the PC with the drift controller on top which keeps the signal stable on frequency.
on the right the PC for the demodulation with speaker on top.
My sat dish is not properly aligned to the sat so the signals are weaker.
Does someone know what signals cause those "lines" every few khz in the spectrum as seen in DL3CWS second pic?
I found the source of those "line" signals on 956MHz.
There is a GSM station not far away and those signals are from this station.
This GSM band goes fm abt 920 to 960MHz, so no wonder...
They are so strong that they manage to get in the coax cable without any antenna connected
Thank god on the NB downlink freqs (739-740MHz) are no interfering signals here.
Also switching the LO could help too. Currently 9,75GHz.
Thank you DH2VA,
thats close, if this filter is available with N connectors i will buy one.
I am using two of the RTL SDR Sticks in metal case with build in TCXO.
With normal sticks without tcxo i can not archive this excellent drift compensation with sofware.
A soon as EH2 is on its final position the dish (135cm) will be correct aligned.
I can receive the 11205 beacon (V) and drift compensation with the beacon from 10706 shows no difference > same sat.
The 11205 beacon is very weaker here than the 10706 beacon.
My dish is still pointing at the badr sats on 26°
I measured a efficiency of about 30% with my small Andrew amp, that seems not to bad.
It looks like the most SSPAs which where formerly used at about 2.17GHz are not very efficient on 2,4GHz.
The used LDMOS transistors are often matched to 2.17GHz and so the tuning to 2.4GHz is not so easy in all cases.
But the needed 10W should be reachable with an usual middle size UMTS amplifier.
For some backup if the small PA is to weak i have another Ericsson and a Nokia SSPA here. Not tuned or modified till now.
i'm curious what types of amplifiers you plan to use for the NB uplink on 2,4GHz?
I heard many would use those "spectrian" amplifiers from the USA.
My first attempt will be with an small "Andrew" amplifier with just one MRF21045.
With 500mW input power this device deliveres about 12W output.
Has anybody a idea how to build a good lowpass filter to install behind the PA?
Looks like i have interpreted the frequency on the x-axys wrong (2/20khz), my fault.
We will see what operating setup will work best when we are allowed to transmit to the sat.
I will try to find the source of that signals in the next days.
If i disconnect the LNB from power the signals are still present,
so think ist something from a local source, PC (USB?) or similar.
"The reality is surely that over the time of a QSO we do not have to retune"
here an OM tested the D75F and i see a frequency drift about 100Hz in a few seconds:
I wish fun turning the VFO
No, i mean those many weaker signals across the frequency.
Maybe some DTV signal from another sat?
They appear on my spectrum also...
vy73 de DB8TF