thanks for the software
de db8tf
Beiträge von DB8TF
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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.
vy73 DB8TF
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Is the sat spinning in the moment?
The beacon signal level is periodically (ca 30sek) getting weaker and stronger again.
vy73 DB8TF
18:56 everything normal again...
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Here i found the seller of those cut out amplifiers:
https://picclick.fr/13cm-RF-Am…Watt-28-132765013840.html
French, not chinese
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For use on 2,4GHz maybe the anaren filters are better removed?
Usually they are specified for 2,17GHz
vy73 DB8TF
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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
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I use only Schwaiger Kox 135:
http://www.schwaiger.de/de/sat-koaxialkabel-135-db-2068.html
Should be not that bad.
VY73 DB8TF
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Alles anzeigenHere 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?
vy73
Db8TF
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.
vy73 DB8TF
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Thank you DH2VA,
thats close, if this filter is available with N connectors i will buy one.
vy73
DB8TF
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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.
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The datasheets of the L-Com filter mention 50W power:
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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°
VY73 DB8TF
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I saw those L-Com WIFI bandpass units:
http://www.l-com.com/bandpass-…h-q-wifi-bandpass-filters
Maybe they can be retuned to 2,4GHz (if needed)
73 DB8TF
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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.
73 DB8TF
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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.
VY72 DB8TF
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Hello alltogether,
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?
vy73
DB8TF
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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.
vy73
DB8TF
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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.
Vy73 de
DB8TF
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"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:
http://www.dg0opk.darc.de/Octagon_LNB_mod_March2017.html
I wish fun turning the VFO
vy 73
DB8TF
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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
