ChrisEHunter
Q: Where is the circuit schematic and the build instructions?
Asked by ChrisEHunter on 2017-12-01 04:20:15
Q: What is the output impedance? I assume 75 ohms, but you know what happens when you assume!
Asked by frd1963 on 2019-07-26 08:43:34
ChrisEHunter This amplifier is 50Ω input and output. It needs a REGULATED supply of exactly 7.2 Volts and 100 mW of drive. The bandwidth is ~83 MHz to ~117 MHz. DO NOT connect its output directly to an antenna - the second harmonic is significant at around -38dBc. I used a 7-pole lowpass filter with a turnover frequency of 130 MHz and got exactly 5 Watts of clean RF after my filter (second harmonic was now -72dBc at my test frequency of 98.4 MHz).
2020-02-16 07:25:58 Helpful (1)Q: Doues this PA work on Hamradio 2-30 MHz in SSB mode?
Asked by chef 23 on 2019-05-27 12:17:29
ChrisEHunter No - it's not linear enough to amplify AM or SSB. I've used them successfully for VHF FM amplifiers in the 2m (144MHz) band and 70cm (430 MHz) band. 1mW drive yields about 3.2W of RF. After cleaning the output with a lowpass filter (essential), you get 3W of clean RF. A simple PLL driver for 70cm gave me a cheap and effective 3W transmitter - enough power for local contacts and to open up my three local repeaters. It runs quite warm, but I haven't killed one yet!
2019-12-29 10:40:05 Helpful (3)Q: Does this transmit in Stereo or is it just Mono?
Asked by Heyjoe on 2018-10-25 02:19:41
ChrisEHunter It doesn't TRANSMIT. It's a RECEIVER!
2019-11-10 04:36:12 Helpful (0)Q: Wich transistor does it have?
Asked by chuledeco on 2019-04-14 10:58:28
ChrisEHunter It's not a transistor. It's an MMIC.
2019-04-17 07:29:55 Helpful (0)
ChrisEHunter C8 sets the transmission frequency (use a plastic tool to adjust this as a metal screwdriver will interfere with the circuit operation). R10 sets the audio input sensitivity so that the level of the audio sent in to the jack socket can be adjusted to prevent over-modulation.
2019-04-17 07:11:50 Helpful (0)Q: Is it possible to attach a antenna, like a big one used for 2 way radios?
Asked by srigleykeegan on 2019-04-05 03:30:42
ChrisEHunter No. The "match" would be completely wrong. This device is designed to feed its little signal into a piece of wire approximately ¼-wavelength long. If the aerial wire is hung vertically, well away from walls, you should get roughly 200m range from this device.
2019-04-17 07:07:42 Helpful (0)Q: Buongiorno non ho capito che potenza a in trasmissione Watt ? Grazie
Asked by domenico on 2018-03-07 07:46:44
ChrisEHunter 1.2 Watts when fully charged
2018-09-17 09:22:48 Helpful (0)
ChrisEHunter Why don't you contact the supplier and get the documentation? The software can be downloaded from the 'net
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Ian Haylock Found this link, looks like the same amp. https://www.aliexpress.com/item/Class-A-6J5-Vacuum-Tube-Pre-amp-Preamp-HiFi-Headphone-Amplifier-DIY-KIT/32570245073.html
2018-02-28 12:45:58 Helpful (1)