One SWR issue I have experienced is that some PL259 barrels (threaded rings) are too long for the short SO239 jacks on the back. So if you notice that the center conductors can still move in and out one the rings are tight, then you probably need to use a different style PL259. Or.. I took a belt sander and ground off about 1/16” off the leading edge of the barrel to allow the center to fully seat before the barrel bottomed out on the SO239. 73! WR9R
All is fine. To get precise 1:1, the amp design would need either a strong attenuation network, which would lower the amplifier gain, or a matching network for each band, which is not reasonable. The swr difference is due to the power transistor input impedance, which is frequency dependant.
Sometimes at low powers the reflected power isn't sufficient to give accurate results with diode based detectors. If you have a directional coupler or can make one and use it with a spec analyser, it may give different results. The drive level may change results also. But the moderate SWR looks excellent.
Driving QRP levels into the amp will not hurt the radio at 1.35 SWR, as long as the amp output is ok is clean. Has @TheSmokinApe checked how clean the amp output is? Takes more attenuators than an HT.
I know this can't happen, but I wish that every device out there had to go through this test and have the video posted publicly before getting an FCC number!
people get to worried about a little SWR, this is from false advertisement for antennas and other equipment, this simply is nothing to worry about, its HF, if you want perfect 1:1 SWR then run it in a dummy load, or move on and operate! just my opinion, great video explaining what I am talking about.
on the input of a amp. 1.5 SWR or less is fine. some times the coax length can make a difference on some bands. I have found the type of coax from radio to amp can make a difference. poor shielding. bent to far . bad connector. A common problem I find is the coax jumper . test them . I have fixed many RF amps. A good 3 ft jumper like ABR 8X or M & P hyperflex 6 or 7 works great. the MIL spec 58/CU is also good. as well as PTFE coax like RG 316/400/393 . crimp PL 259 can come loose if bend allot. I changed my jumpers to POTAFLEX 7 coax. made to bend a lot. 73's
Personally I would be perfectly happy with those readings. I'm currently thinking of buying a Micro PA50, so great that you are making these videos.
I would recommend looking at the Micro PA 50+ that Tech Minds recently reviewed. That way you get the latest updates.
@@don_n5sktI can’t find that video. Do you have a link?
I am fine with them, I had head some folks saying they were really high so I wanted to test them out 👍
@@Craines ruclips.net/video/boTfTwJnR5c/видео.html
One SWR issue I have experienced is that some PL259 barrels (threaded rings) are too long for the short SO239 jacks on the back. So if you notice that the center conductors can still move in and out one the rings are tight, then you probably need to use a different style PL259. Or.. I took a belt sander and ground off about 1/16” off the leading edge of the barrel to allow the center to fully seat before the barrel bottomed out on the SO239. 73! WR9R
That's nice info, thanks man!
All is fine. To get precise 1:1, the amp design would need either a strong attenuation network, which would lower the amplifier gain, or a matching network for each band, which is not reasonable.
The swr difference is due to the power transistor input impedance, which is frequency dependant.
Totally agree Rafael, thanks for watching 👍
Sometimes at low powers the reflected power isn't sufficient to give accurate results with diode based detectors. If you have a directional coupler or can make one and use it with a spec analyser, it may give different results. The drive level may change results also. But the moderate SWR looks excellent.
Good point tech, thanks for the perspective 👍
Driving QRP levels into the amp will not hurt the radio at 1.35 SWR, as long as the amp output is ok is clean.
Has @TheSmokinApe checked how clean the amp output is? Takes more attenuators than an HT.
Yeah, I’m one team “below 1.5 is fine” and I haven’t check the spurs yet 👍
What is the setup, antenna, micro pa50, tuner then radio - or antenna, tuner, micro pa50, then radio to keep it from tripping?
On the amps that I have, the input SWR is anywhere from 1.3 to 1.5, so this all seems normal to me.
Yeah, I believe it’s fairly typical 👍
I know this can't happen, but I wish that every device out there had to go through this test and have the video posted publicly before getting an FCC number!
Haha, me too!
people get to worried about a little SWR, this is from false advertisement for antennas and other equipment, this simply is nothing to worry about, its HF, if you want perfect 1:1 SWR then run it in a dummy load, or move on and operate! just my opinion, great video explaining what I am talking about.
Hey Jim, thanks for the comment 👍
Compared with MX-P50M, which one would you recommend more?
The Micro PA50, there is actually a PA50+ out now
Great video Ape! What is your keying interface between radio and amp??
Hay Danin. The amp has auto sense, so I just set the delay and it detects when I key.
on the input of a amp. 1.5 SWR or less is fine. some times the coax length can make a difference on some bands. I have found the type of coax from radio to amp can make a difference. poor shielding. bent to far . bad connector. A common problem I find is the coax jumper . test them . I have fixed many RF amps. A good 3 ft jumper like ABR 8X or M & P hyperflex 6 or 7 works great. the MIL spec 58/CU is also good. as well as PTFE coax like RG 316/400/393 . crimp PL 259 can come loose if bend allot. I changed my jumpers to POTAFLEX 7 coax. made to bend a lot. 73's
Good info, connectors can be a problem for sure 👍
Great video! Thanks. Do other amplifiers increase the SWR to the radio?
My 811H did and I have seen other amps do it. My Mercury IIIs does not but YMMV.
The ogs-50 PA had very high swr on the input. A mod had to be done to make it safe for the radio
A decent amp should be below 1.5 👍
@@TheSmokinApe Thanks Ape
Hey Ape! What kind of swr readings was the radio showing on tx?
When I tested without the SWR meter in-line they were about the same 👍
Thanks! Good to know. It is a pretty nice little amp. @@TheSmokinApe
The Mirco PA50, hmmmm, may have to go on the "buy" list. Next decision, pay the mortgage, or buy more radio gear?
I’d vote for more radio gear. But hold off until I test the spurs 👍
@@TheSmokinApe dang those spurs!
if 12v 0.5w input ......output power? i wonder best regards
it will vary with band
The New "Micro PA50 +(Plus)" Model is supposed to have fixed this
The problem is I already bought this one 🤔
@@TheSmokinApe O.K...
Is it happening when the amp is hot? Or dodgy cables.
It’s fairly typical to see a higher than 1:1 input impedance on an amplifier, anything below 1.5 is fine 👍
Maybe the input impedance of the amp is not 50 ohms. You could analyze with a VNA, and then add a matching network.
Yep, that can be done. I am not seeing a large enough of an issue with this one to worry about it...
Unless the input SWR exceeds 2:1 those commenters need to find something else to complain about.
Lol, I prefer 1.5 just because you said 2! Thanks for watching Hank 👍