Now, that makes sense.
i saw that it is really important WHERE you place the copper foil.
And because of that you must try and move the foil till you are satisfied with the results. Changes from one PA to another.
vy73 DB8TF
Now, that makes sense.
i saw that it is really important WHERE you place the copper foil.
And because of that you must try and move the foil till you are satisfied with the results. Changes from one PA to another.
vy73 DB8TF
Do you know why that is ? And why it flies in the face of logic ?
BTW I just Googled "UMTS PA Mods" and came up with nothing ?
I dont' know why but with added capacity it works far better.
On my Ericcson UMTS PA no modification on the input or output works best.
So it seems that this rule of adding capacity works not on all UMTS PAs.
Maybe with this MRF21045 adding capacity helps and with other LDMOS not.
Try it for yourself and see. If you find a better way then let us know.
In this Pic: What TX amplifier do you plan to use? it also looks like he added some caps to the preamp?
vy73 DB8TF
Surely adding capacitance "lowers" the frequency ? Where as we want to go "higher" from 2.1/2.2 to 2.4 ?
Dave
I clearly tried first to decrease (smaller PCB tracks) the capacitance, but the results were not good.
Google for UMTS PA Mods and you will see only Pictures with Increased capacitances.
vy73 DB8TF
@BG0AUB
those Little copper pieces act as additional capacitors on the input and output pcb tracks and help to optimize the matching of the normally for (2,17GHz) UMTS freq designed circuits and internally matched LDMOS.
You could calculate the needed capacitances and the position where to install them but i used the "try&fail" method till i achieved a (for me) satisfying output level from the PA.
I got max. 16W out with 500mW drive from this MRF21045 (IDq 300mA) and that is not bad.
Vy73 DB8TF
Hi OMs,
because nearly every day a couple of emails arrive here about the modification of the small Andrew MRF21045 amplifier i digged mine out of the pile of "old" amplifiers and took some pictures.
vy73 DB8TF
That won't help you much, just try and increase the PCB tracks until you get max power. Start on the input path an then modify the output till you are satisfied.
If you get 15W out of that little PA then be happy.
And of course after modification measure with spectrum analyzer for unwanted signals from the PA or use a good bandpass filter after it.
Do you own the needed measuring equipment for working on a 2,4GHz PA?
At least a PWR/SWR meter for 2,4GHz is needed.
EA4HEW: how do you define "easy"
Found in another forum, may be interesting:
http://satellitenempfang.info/schuesselgroessen.html
vy 73 DB8TF
Looks promising
vy73 DB8TF
Hi George,
when you have finished your modification and tests with this LNB i would be happy to add your informations to the LNB spreadsheet.
vy73 DB8TF
I can confirm that with ext ref the wobbling on all LNBs that i modified was gone.
But for my beloved SW drift correction i wanted a unmodified an wobble-free LNB
The old and new Octagons and the Opticum AX Black Buster are performing well.
No luck with GM201 and HD Line Black Premium 2.
A 80cms dish with 4turn helical feed has about 10dB more gain than that grid antenna.
I have the same here and compared the two antennas.
And on the pic from wimo the front reflector is wrong mounted
Correct assembled and with enough TX power it is usable.
So i assume this signal is on the 10GHz side and not via the P4A transponder?
Then the solution would be a even bigger dish (or better aligned) to get the TP stronger?
It's annoying, the TP floor is jumping here every 10secs.
vy73 DB8TF
The signal is also receiveable on the goonhilly websdr and on the websdr on sicilia.
No local source...
Now it can be heard even in the middle of the P4A TP.
Switch to AM and listen to it. Every ca 10secs a burst appears..
Maybe it was a little bit to much decreasing in TP level lately?
Or is the source on 2,4GHz?
Prior to changing the TP level i didn't recognize that signal.
vy73 DB8TF
Here are 2 pictures, one Opticum AX LNB which gives a clear signal and a GM201 which "wobbles".
Here is the recording of the Opticum:
https://vocaroo.com/i/s1mvvw5hMvhV
Here in comparison the GM201:
https://vocaroo.com/i/s0eSGAUm5gsA
Both LNB AFs are SW corrected with 1Hz steps.
The Opticum was already warmed up, the GM201 was currently warming up.
No wind here, no vibrations on the LNBs.
Maybe i have unluckily bought 4 GM201 LNBs one HD Line BP2 which are bad ones?
No wobbling problems with the Octagons and the Opticum.
vy73 DB8TF
Hi Peter,
the "wobbling" is a constant changing LO freq with +/- 50-400Hz per second in both directions. In german we would say the cw beacon "jault".
It has nothing to do with the long term frequency drift.
It is not depending on vibration or temperature changes.
On the TFF1017 PLLs (GM201)and the HD Line BP2 it can be seen (and of course heard!) if you tune to the CW beacon.
I take some pictures, so it would be clear what is meant.
Vy73 DB8TF
OK Mike, go on and take a picture of the Goobay LNB on the CW Beacon, about 1 min and VBW 1kHz on the waterfall.
I will change the data in the list if there is no wobbling.
Also i will (if you agree) include the link to your pic.
Vy73 DB8TF
Also tested the Opticum AX Black Buster Twin today and as DG0OPK already wrote this LNB shows now signs of any wobbling. Drift is normal for a unmodified LNB.
So far the closest solution to replace the old Octagon
vy73