Looking for what device this is. They’ve put a sticker over it but also been rubbed off once you remove it. They seem to use the same amp but change the chip for 120w - 200w and 300w
https://a.aliexpress.com/_mMaScr4
What device is this amp using ?
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reverend
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Re: What device is this amp using ?
They use various devices, mostly taken out of old cellular amplifiers. The MRF9180 is one example.
if it ain't broke, keep tweaking
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BriansBrain
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Re: What device is this amp using ?
Mmmmmmmmmm interestingXXL wrote: ↑Thu Dec 29, 2022 5:12 pm Looking for what device this is. They’ve put a sticker over it but also been rubbed off once you remove it. They seem to use the same amp but change the chip for 120w - 200w and 300w
https://a.aliexpress.com/_mMaScr4
High gainOperating power supply: 26-27V
Input power: 0.6-1W
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XXL
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Re: What device is this amp using ?
Is that good or bad ?
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BriansBrain
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Re: What device is this amp using ?
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BriansBrain
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Re: What device is this amp using ?
Here's another even cheaper About €149.73
But without the LPF on ebay
300W 75MHz-120MHz RF Power Amplifier Board Input 27V Working Current 17-18A for FM Transmitter Radio
Specifications:
- Power supply: 27V
- Working current: 17-18A
- Power: 300W (maximum 350W 300W is recommended)
- Frequency range: 75-120MHz
- Input power: 1W
- Output impedance: 50 ohms
- Board size: 10 x 5.4cm/3.9 x 2.1"
But without the LPF on ebay
300W 75MHz-120MHz RF Power Amplifier Board Input 27V Working Current 17-18A for FM Transmitter Radio
Specifications:
- Power supply: 27V
- Working current: 17-18A
- Power: 300W (maximum 350W 300W is recommended)
- Frequency range: 75-120MHz
- Input power: 1W
- Output impedance: 50 ohms
- Board size: 10 x 5.4cm/3.9 x 2.1"
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BriansBrain
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Re: What device is this amp using ?
OK I'm guessing it's a SRF261
It doesn't have the normal mounting flange with the holes for mounting
So they have soldered one on
It doesn't have the normal mounting flange with the holes for mounting
So they have soldered one on
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BriansBrain
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Re: What device is this amp using ?
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jvok
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Re: What device is this amp using ?
Reckon that heatsinks big enough?
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XXL
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Re: What device is this amp using ?
Won’t that solder just melt with the heat ? Also what would the 200w device be ? I don’t think it would be an mrf9180.
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Albert H
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Re: What device is this amp using ?
The output short circuit test in that video is scary!
The harmonic outputs from that PA are rather nasty - the second is around 48 - 54 dB below the carrier, and the third is generally a bit worse. It would need a good lowpass filter after it to make sure it wouldn't cause interference. You'll notice that they've set the spectrum analyser to show only up to the third - it's probably producing more harmonics above that. The lowpass filter capacitors will be expensive, since they'll have a pretty big voltage across them.
The harmonic outputs from that PA are rather nasty - the second is around 48 - 54 dB below the carrier, and the third is generally a bit worse. It would need a good lowpass filter after it to make sure it wouldn't cause interference. You'll notice that they've set the spectrum analyser to show only up to the third - it's probably producing more harmonics above that. The lowpass filter capacitors will be expensive, since they'll have a pretty big voltage across them.
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