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PA300W - усилитель 300 Вт для SDR от 0,3 Вт

Admin: LPF+ШПУ в процессе производства 300 Вт

Ответов - 42, стр: 1 2 3 All

zurdo: *PRIVAT*

Admin: zurdo пишет: Admin, как понимаю такие впечатляющие характеристики УМ 300 по IMD получены благодаря диплексору? - Такие характеристики получены, в первую очередь, благодаря питанию 50 В, и во-вторую, диплексеру.

zurdo: Т.е. вы хотите сказать, что чем выше напряжение питания при заданной мощности, тем выше линейность УМ. Я правильно понял?


r3kr: День добрый! 50 V современные транзисторы более линейные чем 12 V - это известно давно ,и можно этот параметр посмотреть в даташите IMD

zurdo: В датащите указано посредственное значение IMD 32 дБ при номинальных 50 В.

r3kr: zurdo пишет: IMD 32 дБ Это касаемо каких транзисторов? Дайте, пожалуйста, ссылку, где вы это нашли.

r3kr: Если почитать Alldatasheet внимательно последний абзац CLASS A PERFORMANCE, то станет ясно - типовое значение IMD при 50V и при 50W -50dBc/ А мы снимаем всего 10Вт. Так что, все реально. По-поводу SSD2933, мы снимаем с каждого 150Вт всего, вместо типовых 300Вт, и работаем в классе АВ, при токе покоя 900 мА. zurdo Спасибо за ваши сомнения, только так можно найти истину и рассказать о ней.

zurdo: Пардон, всех запутал - говорю про последний каскад на SD2933, а ссылаюсь на датащит транзистора из первого каскада.

qlc: Вот здесь http://www.ab4oj.com/sdr/apache/anan100d_notes.pdf описано исследование ANAN-100 выполненное AB4OJ на манер публикуемых в QST измерений лаборатории ARRL.

qlc: Измеренные спектроанализатором KC901H уровни второй и третьей гармоник усилителя 300 Вт (с 0.3 Вт входных) после фильтра на нагрузке 50 Ом . Measured by KC901H network analyser suppression of second and third harmonics (amplifier with diplexer) is: 10 meters 2nd -52 dB 3rd -55 dB 20 meters 2nd -54 dB 3rd -47 dB 80 meters 2nd -53 dB 3rd -51 dB. See pictures below. 10 м Подавление второй гармоники -52 дБ (0.00000631 раз по мощности), третьей -55 дБ (0.00000316 раз по мощности). 20 м Подавление второй гармоники -54 дБ, третьей -47 дБ. 80 м Подавление второй гармоники -53 дБ, третьей -51 дБ.

qlc: USER MANUAL how to configure PowerSDR software for use with HERMES SDR, BPF and 300W amplifier. 1.This manual is written for PowerSDR mRX version 3.1.5 . Later versions may have some differencies, but generally the same. 2.At first, before switching on the “Power”, open the tab “General” on Setup menu and set Radio Model to ANAN-10. 3. Open the tab ANAN Ctrl and mark the boxes as shown on picture below. The J16 pins Out1 to Out1 are used to control the BPF and LPF filters band-by-band. Pin Out5 activates attenuator -20 dB on BPF board always on transmit. You can use it on low band for receiving also, just mark the box for certain band on the left table. 4. Open Ant/Filters tab and mark the box “Att on TX”. This makes additional safe for your onboard receiver. Then clear the box “Disable on Tune”. This permits the drive power reduction whet SWR exceeds 2:1 . See the picture below. 5. Open the tab “PA gain” and increase the numbers for all HF bands for 45 – 47 dB. It is made to prevent the overdrive of 300W amplifier. Then you must set the drive control to 100% on each band from 10 to 160 meters and correct the gain band-by-band up or down to achieve full 300 W from the amplifier. Please take care about heating of radiator. First stage works in Class A with IDQ 1 A and second in Class AB with IDQ 0.9 A per transistor. Thus it becomes hot even without modulation in SSB mode if you leave it with MOX ON for prolonged time. Forced air cooling is needed. See the picture below as a referense. Your figures will differ for sure. 6. Now you can start the operation by clicking the “Power” button.

Admin: Мастер-класс от DL5AI http://www.qrz.com/db/DL5AI

Admin: Усилитель PA03-300W от DJ5DM

Ray: I have almost completed the construction of the components on the P300 and have 5 questions. I have looked at the FORUM with Google translation and some useful information with photo's there. I used 6.4mm copper tube for L6 in the output transformer for the 300W PA which worked well. Question 1. The LPF300W. The schematic is I think not correct for the connection of the 1T winding in the SWR transformer PA to ANT relay. PCB is correct I think. Please send some detail how to connect the 2 8T windings on the PCB? The photo's on the FORUM do not show it clearly. Question 2. The 300W-PA. The construction of transformer L3,L4,L5 shows double wires for L4 and L5 in the photo. Is it correct that for L4 and L5 there should be 2T of double wires? You did not send enough PTFE wire for that. No problem but if it needs double wire I can change it. Up to 5A dc in each winding I think. Question 3. The 300W-PA. The transformer L1,L2. The FORUM shows the 1T winding for L2 made with coax cable braid. Is this important? Can it be 1.2mm copper wire? Question 4. The 300W-PA. The thermistor t 10K is not shown any detail. In the FORUM there is a photo showing the t 10K thermally attached to a FET SD2933. Is this correct and where is the place to attach the GND connection of the t 10K? Question 5. Attachment to the heatsink radiator. What is the spacing between the heatsink radiator surface and the underside of the PCB in mm? I think the S,G,D connection tab's of the FET's need to bend upwards a small amount because if they lay flat on the PCB the clearance under the PCB is too small to ensure no short circuit somewhere under the PCB to the heatsink radiator. Should all the screw holes (12x) in the PCB have a screw into the heatsink radiator or just the 4x as shown in the photo's? I think the PCB will flex too much in the middle if only 4x screws are used. I have drilled and tapped 3mm for all screw places and for the FET's. You can include my questions in the FORUM if you want to. In english or translated, I dont' mind. 73 Ray

qlc: Ray пишет: Question 1. The LPF300W. The schematic is I think not correct for the connection of the 1T winding in the SWR transformer PA to ANT relay. PCB is correct I think. Please send some detail how to connect the 2 8T windings on the PCB? The photo's on the FORUM do not show it clearly. Ray пишет: Question 2. The 300W-PA. The construction of transformer L3,L4,L5 shows double wires for L4 and L5 in the photo. Is it correct that for L4 and L5 there should be 2T of double wires? You did not send enough PTFE wire for that. No problem but if it needs double wire I can change it. Up to 5A dc in each winding I think. We are using 2 wires because short of one with large diameter. Use PTFE wire which you have Ray пишет: Question 3. The 300W-PA. The transformer L1,L2. The FORUM shows the 1T winding for L2 made with coax cable braid. Is this important? Can it be 1.2mm copper wire? I suggest to make like this click here Ray пишет: Question 4. The 300W-PA. The thermistor t 10K is not shown any detail. In the FORUM there is a photo showing the t 10K thermally attached to a FET SD2933. Is this correct and where is the place to attach the GND connection of the t 10K? You may solder the GND pin of thermistor directly to source of MOSFET Ray пишет: Question 5. Attachment to the heatsink radiator. What is the spacing between the heatsink radiator surface and the underside of the PCB in mm? I think the S,G,D connection tab's of the FET's need to bend upwards a small amount because if they lay flat on the PCB the clearance under the PCB is too small to ensure no short circuit somewhere under the PCB to the heatsink radiator. Should all the screw holes (12x) in the PCB have a screw into the heatsink radiator or just the 4x as shown in the photo's? I think the PCB will flex too much in the middle if only 4x screws are used. I have drilled and tapped 3mm for all screw places and for the FET's. We use 6 screws: 4 in the corners , one close to 15-pin connector and last on the opposite side of PCB. We are using one M4 nut as a spreader between PCB and heatsink, but 3 mm is enough.



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