Hybrid RF CATV modules power  - Page 1
Forum section: electronics / rf-microwave

author: Teknow
author_rank: Regular Contributor
timestamp: March 30, 2018, 05:19:56 pm
content: Someone told me that the BGY65 which is a hybrid wide band RF power amplifier module can deliver a 100 W power into 50 Ohms. As I caught up only with (some modest) math and quite late in my life, I can't tell on my own whether this is true or not. I simply calculated (from the datasheet) the module's maximum current * the voltage= power!24V*0.250=6.25W.I also would like to know the max power output of MHW5342A, should I calculate the RF power output as I simply multiplied (P=IE) above or is there another formula?I quote the following information from the datasheet for MHW5342A for volunteers:"Gp = 34.5 dB Typ @ 50 MHzGp = 35.5 dB Typ @ 450 MHzRF Voltage Input (Single Tone) Vin +55 dBmVDC Supply Voltage VCC +28 VdcDC Current IDC — 310-340 mA"thanks for the help in advanceI also need to calculate the RF power output into 50 Ohms forBGY65MHW5342Aand CA901Aand how much should the power input be in terms of mw not dBuV!!!!

author: German_EE
author_rank: Super Contributor
timestamp: March 30, 2018, 07:57:00 pm
content: For some reason the CATV people grew up in their own separate world with 75 ohm lines and measurement in dBuV, damn confusing, especially when you want to use some CATV chips in a ham radio project.I feel your pain, and I can offer a solution:http://www.temcom.com/db-calculator/This may also help as it works at both 50 ohm and 75 ohm and will convert between the twohttps://www.random-science-tools.com/electronics/dBm-Watts-volts.htm

author: dmills
author_rank: Super Contributor
timestamp: March 30, 2018, 07:57:43 pm
content: Those are DC input powers you are calculating, RF output will be less, generally a lot less, I would bet on maybe a half watt of output at 1dB compression from these class A modules into 75 ohms (Good luck getting them BTW they are way obsolete).All the CATV stuff is specified into 75 ohms not 50, not that it much matters at these power levels.Also, note that abs max is not a place you ever want to be, +55dBmv is -5dBV a nads over half a volt, waay more then the things will be linear with.The only way you are getting 100W out of these is during a lightning strike!Regards, Dan.

author: Teknow
author_rank: Regular Contributor
timestamp: March 31, 2018, 07:49:53 am
content: Thanks a lot German _EE for the reply and the useful suggestions. I added the sites to my RF bookmarks.And thanks a lot to you Dan you boosted my morale with your humor.It's true I bought the Motorola Hybrids from the flee market.I was tricked into buying them for their giant housing and the large heat sinks!

author: dmills
author_rank: Super Contributor
timestamp: March 31, 2018, 04:24:17 pm
content: What these are GOOD for, is LO (and broadband RF output isolation) amplifiers for high level mixers, being as they are superbly linear and a good match power wise for a level 13 or possibly even level 17 diode ring mixer.As usual a modest pad to help absorb the reflections from the diode ring will help with linearity.73, Dan.

author: Teknow
author_rank: Regular Contributor
timestamp: March 31, 2018, 06:30:21 pm
content: Yes, although their noise figure is not low despite their linearity. I'm interested in using them in a wideband RF frequency generator, or test amplifiers for RF VCOs and oscillators.

author: dmills
author_rank: Super Contributor
timestamp: March 31, 2018, 07:07:31 pm
content: Not a horrible application, but you may find an ADSL line driver to be more useful, standard silicon and they can drive +20dBm or so up into the low VHF.73 Dan.

author: German_EE
author_rank: Super Contributor
timestamp: April 02, 2018, 07:42:28 am
content: You two have discovered a little known secret here. The CATV folk are passionate about amplifier linearity with the ADSL chipset vendors not far behind. In both cases they need amazing performance so that the signals are still of decent quality after being sent along long lengths of cable whilst being mixed with dozens of other signals.As radio amateurs we can make use of this technology and create amplifier chains with high linearity and low IP3 figures. A clean signal is always a good thing.