Posts by DB8TF
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i think in ibiza is no 2,4ghz transmission allowed for non EA hams?
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connect the output with your semirigid direct on the input pad from the removed output circulator.
vy73 , see you on 20dBW soon
DB8TF
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To solve the (similar) BU500 power up problem with slowly rising voltage i use a small relais which is connected to VCC via a series resistor and a parallel capacitor.
So this relais switches the VCC to the BU500 after about 1 sec (when the C is charged)
and the VCC is stable.
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Set the SUT fuses to 10 for slowly rising power.
Page 25 >
http://ww1.microchip.com/downloads/en/DeviceDoc/doc8126.pdf
VY73 DB8TF
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Hi Richard, i also had a small drawback….
The J530 Anaren Xinger i used as output combiner (rated at 50W CW) changend his aggregate state yesterday from solid to smoke
…but luckily no damage to the output BLDs
. They are really solid.So i changed the Xinger (again a J503) and added a 3dB ATT on the amp Input.
Now the Xinger should be able to handle the Output power.. (max 60W now).
VY73s DB8TF
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Maybe some screenshots explain it better:
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DL1EMA starts with dB(m) so he wanted a value that could be "measured" and not be guessed.
73s
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Take the NBTP floor as S0 (ca -127dB) and then the CW beacon has abt S5+3dB.
Strong stations have a signal about S6.
Everything above is unwanted and to much uplink power.
The strongest HAM station i saw till now had S7+3dB. (SSB)
BTW, Forget the S-Meters on the WEB-SDRs they are all wrong.
VY73 DB8TF
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Frage an die AMSAT-DL:
Ist die automatische Aussendung von DL0NOT (DL1ZAV) (.640) auf dem Satelliten gewünscht oder in irgendeiner Form mit der AMSAT-DL abgesprochen?
Ich persönlich finde es absolut sinnfrei einen Ostseerundspruch (die ganze Woche denselben!) oder dergleichen jeden Tag auf einem GEO Sat auszusenden.
Hier ein Link zum Thema: https://www.ostseerundspruch.d…spruch-nr-265-kw-28-2019/
BTW, es werden nicht nur zu zwei Uhrzeiten die Rundsprüche gesendet sondern alle paar Minuten eine Kennung. Diese Frequenz wird seit Inbetriebnahme des Sat für D/SSTV verwendet und es wurden schon mehrere D/SSTV Sendungen durch diesen Rundspruch/Kennung gestört.
Gruß
DB8TF
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What CPU are you using?
With a I3 i had the same issue, on a faster I5 this buffer never reaches 100
VY73 DB8TF
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Aha, you set a "trap"..
BTW, this ring device is called "circulator"
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Is this circulator really 1500-1700MHz?
Then it won't work on 2,4GHz properly.
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I bought three of those directional couplers on eBay and they work very well for measuring PA output power.
The coupling value can be selected 10/20/30/40dB. (and some more)
Those directional couplers are sold by many sellers and also on amazon & Co. for a few bucks.
https://www.ebay.de/itm/1stck-…m:mT6rnKMBsPYpjotZjzsa11w
At "Antons Funkperlen" website are photos from the inside: http://funkperlen.blogspot.com…htkoppler-fur-7-euro.htmlEdit: attached a picture of a measurement on my 30db coupler
VY73 DB8TF
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G0MJW : for a split second
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Edit: The output combiner is only rated at 105/145W and whilst the p1dB of each device is 110W I suspect it would blow up if I pushed it any harder than 80W.
Richard those MRF7S2110s are internally matched to 2,1GHz so be happy if you reach abt. 30% of the rated power on 2,4GHz. Expect 40-45W per device.
73s DB8TF
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PA and BU500 now "married" and first (and only) fullpower test shows peak 12dB above CW beacon (with the WiFi barbecue dish).
VY73 DB8TF
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After some more modifications (IDq on the driver) now i'm satisfied with the performance of the BLD amp.
For sure a good cooling is needed to dissipate those 400W heat on full pwr but how often will I use that much power?
For all of you which try to mod this amp i recommend to remove the internal IDq regulation circuits on ALL LDMOS, they seem to have a problem (maybe old c's or those LDMOS internal current senses?).
The IDq regulating circuit on the preamp e.g. wildly jumps from nothing to ca. 500mA and back , therefore the output was more than unstable, so i removed it.
VY73 DB8TF (qrp)
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Here is a french site where they sell surplus WCDMA amplifiers cheap(er than our friend from poland).
Could be interesting for OMs who would mod such amps for 2,4GHz themselves.
(I would buy there if i not already had 5 amps around here
)
