Yes, like Achim said , that delivers the most spectral pure impact. With these multi carrier signals it's not anymore 'adjust bias for max output' (like with single carriers in the old days ; -)
What TX amplifier do you plan to use?
-
-
Even so, it might be worth some experimentation with the operating point in actual use. IMDs of-30dB would not be acceptable in a commercial terrestrial application.
Mike
-
Andrew MRF21045 helps what value should the polarization voltage have? I got about 3v 1 watts 0.6a or so with 3.3v 0.8a 2.5 watts if I increase the bias voltage 3.4v starts consume rest
-
For mrf21045, my bias voltage is 2.7-3.0, 0.55-0.9a at 24v, and 42DB is output when 30DB is input
-
Quote
For mrf21045, my bias voltage is 2.7-3.0, 0.55-0.9a at 24v, and 42DB is output when 30DB is input
So you have 12dB gain? 42dBm out for 30dBm input.
I wonder if 50W output is possible, perhaps the internal matching is not so good at 2400. (28V and 14.7dB gain at 2200MHz on datasheet)
David
-
For mrf21045, my bias voltage is 2.7-3.0, 0.55-0.9a at 24v, and 42DB is output when 30DB is input
thank you all, sorry, but the 500 mA current must be measured on the Vg? bias MRF2104
-
-
thank BG0AUB , I made some improvements by obtaining with input 0.5 at the output 2 watts bias 3v and with 3.7v bias 9watt
vcc 27v
73 Roberto
-
May increase the input level value, reduce a little bias voltage...Mrf21045 seems to be very not easy damaged, I never burned in all of the tests.
-
I ak using modified Andrew PA with MRF. Measured gain around 10,5dB with possible match till 2360MHz. Tried several tweaks but witout luck.
Works on 2400MHz with not good match but Can deliver around 12 - 15W from 2W. Bias 0,5A at least! With lower bias amplifier lost gain.
-
thank bg0aub
-
-
-
Ok, I solved PA now works at 13 watts and 0.5 mA, as a driver for tests of use of Chinese Tiquin 27 dbm out ebay but personally I don't li
73 Roberto
-
Just finished modifying another UMTS PA (BLF8G22LS-160BV) this time for OM DM4DS Sandor.
Max power easy over 100W but as my power attenuator gets very hot i stopped @ 100W (320mW drive).
Signal looks clean on spectrum analyzer.
I attached some pictures from the testbench and the used equipment.
73s DB8TF
Hi great, I see you use the Daiwa power meter but the power returned 2.4ghz?
Roberto
-
Hi Roberto,
i don't understand your question
-
sorry all post me I correct 0,5 A IR , hello db8tf excuse me model model of the daiwa
Roberto
-
-
Update:
the amp burned all PCB trace behind the combiner after 30 seconds on DATV with ~35W.
Flo tried to repair it but was not able to do. Now it´s running only on 1 Transistor and running ~35W with very bad efficency.
I modified myself another one and this one is doing 150W @ 28V @ 16A without any problems.
GreetingsSandor
DM4DSOld Post
--------------------------------------
Today i got the PA from DB8TF - Flo back . Amazing.
Pictures #225
First QSO was with Flo and its fantastic. For SSB it´s quick too much power with my 1.2m dish. I think it´s easy to trigger LeiLA , we didn´t!
In KG-STV super clear Eye-diagram.
After i figured out how to stream the small ksyms, i´m good for some DATV
Thanks again Flo. Surprise follows! -
Hi DB8TF,
Great work!
Could you please share what are the changes you have done to the board?I own the same PA unit, however I’m trying to figure out what changes need to be done.
I see that you have replaced the input connector with SMA (BTW, what is the original connector?)
And that the circulator was replaced with a N-type. There are few copper patches (I assume for better matching). What changes are not so obvious? Is the amplifier still working as a Doherty one?
thanks
Yoram