The TinySA is cheap and with a little self training every ham these days has the opportunity to have an analyzer that will do all the average ham needs. It will do harmonic measurements for you. With the NanoVNA,and the TinySA the excuse of not having the right test equipment in the shack is not valid anymore. There are ample of free on line tutorials, both are darn easy to learn. Just make sure you buy an original and not a clone, go to the respective websites and look who sells authorized original units, the clones have a wide range of problems with the biggest being accuracy and some of them can not be updated to the newest software/ features.
@@TheSmokinApe I have a nanovna. I need to find a attenuator so I can do this test on a PA. Where did you get your attenuator and what brand is it? I cant find anything on line but qrp attenuators.
I'm enjoying watching as you learn more and more about ham radio. There's no reason not to use the amp. I assume ANY amplifier I get has spurs, and that an external low-pass filter will likely be required. Fortunately for us as hams they are cheap and easy to build, and we are licensed to build and use those filters. You have a good spectrum analyzer and power attenuator sitting right in front of you. Go for it.
Hey John. I have this thing field stripped right now, the plan is to attempt a fix internally and if that doesn't work we'll go the external route. Thanks for the comment 👍
Spurious emissions is normal from this amplifier if the input is overdriven. Keep the input to 3.5W or so, and harmonics should be well below 50dBc. But on the other hand, the production line for these amplifiers may give some variance. It's not a 6-sigma factory I guess.
@@TheSmokinApe guess just following the traces should work 🤔I don't believe the filters there are too complicated. another idea could be adding an external LPF there, but well this is far from ideal 🤷♂
Thanks for this test. Glad to see it has the output filtering. Going to put one after my Flex 1500 to get 25 Watts to drive my Elecraft KPA500 to full power. Tried a different Chicom unit without filtering and it drove my KPA500 nuts.
Can you just do 20 but use the Hermes to generate the signal? (I am still gonna use mine) also, when you adjust the power down, to say 20w out, does it meet spec? Thanks Ape
I wonder if there are a set of LPF Low Pass Filters in this unit. If not, perhaps you could just add one for the 20m band ? I suppose 17 meters should be checked.
Excellent ! The screen captures would have been awesome. I have had the same trouble getting them to save on a lot of this newer test equipment. Thanks for sharing !
Good topic Ape. I am curious. I like using mine too. I think that power increase can be upgraded to causation, the evidence is far more direct than the statistical approaches that indicate a correlation. I am curious now about 12, 15, and 17M emissions. I will avoid using it on 20, this might mean the end of my idea of pairing it to a Hermes Lite.
Well, that's a shame as I was going to buy one...but good to know. Wonder if they're all like it, or if it's the usual lucky dip type scenario. What filtering do they run, out of interest?
80 / 40M should be tested with a span of 50Mhz so you can see the harmonics better if there are any, a 500Mhz span doesn't give enough resolution at the low end. 20 and up a 100Mhz span is sufficient. On 20m look if you can reduce the drive and see what happens, you might just have a sweet spot in the input and overdrive the transistors slightly.
I did vary the power and frequency a bit on 20m and the harmonic persisted. I’m thinking there’s a problem with that particular filter. I’ll be releasing another video focusing on that.
Surely to be meaningful the test should show spectrum analyser results for both the input and the output. Also, the test needs to show the input power level. I did own one of these amplifiers and it was well within specifications ... PROVIDED it wasn't overdriven. These amplifiers are rated at 45 Watts maximum output but at that level they are really starting to become non-linear. Keep them under 40 Watts and they're fine.
@@TheSmokinApe Mine was fine up to around 35 Watts. By 40 Watts it was starting to saturate and at 45 Watts it was saturating badly and was completely non-linear. I suspect there’s some variation. There’s not a lot of quality control with these products so it can be a bit of a lottery.
3rd harmonic should increase 3dB for every 1dB increase in fundamental. So turning down the exciter should reduce the 3rd harmonic the same way. So perhaps a judicious reduction in power on that problematic band would be wise.
Two comments.. the RF relay topology of those amps is crap .. they use the same relay for both in and out to the LPF selected. This sis guaranteed to cause problems but it's a cheap solution. You get blow-by within the relay. Second. It may be possible to jessy up the performance on 20 mtrs you need to find out what you have there in terms of L s and Cs measured not what's written on the body and not via an AL calc. Then run it through a Bessel filter program an find out where the break point is - some of the filters of that type when sold as stand alone (Ebay) are utter crap. they have never been checked for component tolerances. or were a bad design to start with . Rework it so the break point is sitting either ON 14.3 Mhz or say +20% if you want less power dilution. THen build it with those components . You may with intelligent component selection be able to retain all coils on that band as wound and just pull around the filter by the filter capacitors of which there are likely three. Appn Note 267 from Motorola Is you friend but you won't know what Q has been the basis of the filter design. Everything in that appn note for a Network type B devolves from the selected Q. Nxp now appear to own the intellectual property of that AN. any capacitors replaced have to have precisely the same technology as the existing ones. No Mylar green caps for example are acceptable. TEF
Nice test method Ape! You probably have seen this already, but, you got me interested in learning more Sir! www.ccarc.org.au/wp-content/uploads/2020/11/MX_X50_Amp_blog_by_Peter_VK2EHQ.pdf 73 - KF6IF
Love that you are adding Spectrum Analyzer content. It's legit!!
Thanks Tony, glad you like it!
Interested in what the output pf the 705 was at that frequency as well. Great show of a test
I think a round two is in order...
Not everyone has spectrum analyzer and knowledge to make such tests. Thank you for effort. 73
The TinySA is cheap and with a little self training every ham these days has the opportunity to have an analyzer that will do all the average ham needs. It will do harmonic measurements for you. With the NanoVNA,and the TinySA the excuse of not having the right test equipment in the shack is not valid anymore. There are ample of free on line tutorials, both are darn easy to learn. Just make sure you buy an original and not a clone, go to the respective websites and look who sells authorized original units, the clones have a wide range of problems with the biggest being accuracy and some of them can not be updated to the newest software/ features.
Glad to do it Pasje, thanks for watching 👍
Totally agree German John, they are total game changers.
@@TheSmokinApe I have a nanovna. I need to find a attenuator so I can do this test on a PA. Where did you get your attenuator and what brand is it? I cant find anything on line but qrp attenuators.
I'm enjoying watching as you learn more and more about ham radio.
There's no reason not to use the amp. I assume ANY amplifier I get has spurs, and that an external low-pass filter will likely be required. Fortunately for us as hams they are cheap and easy to build, and we are licensed to build and use those filters. You have a good spectrum analyzer and power attenuator sitting right in front of you. Go for it.
Hey John. I have this thing field stripped right now, the plan is to attempt a fix internally and if that doesn't work we'll go the external route. Thanks for the comment 👍
@@TheSmokinApe, I'd guess if you put a NanoVNA on that low-pass filter you'll find one of the toroid's windings needs adjusting.
Spurious emissions is normal from this amplifier if the input is overdriven. Keep the input to 3.5W or so, and harmonics should be well below 50dBc. But on the other hand, the production line for these amplifiers may give some variance. It's not a 6-sigma factory I guess.
Thanks! That's the kind of videos i like. No rumors or 'opinions'. Proper facts! 👍
Thanks LabCat 👍
Great video, I really like your spectrum analyzer.
Thanks TEH 👍
Nice to see someone being honest about a product they like! It sucks that it is bad on 20!
Yeah, I’m pretty disappointed about 20. Thanks for watching BA 👍
@@TheSmokinApe You should be able to open it up and adjust the low pass filter for 20m. That would be an interesting video. Cheers
You are a mind reader, I am trying to find the schematic but not having much luck.
@@TheSmokinApe guess just following the traces should work 🤔I don't believe the filters there are too complicated. another idea could be adding an external LPF there, but well this is far from ideal 🤷♂
Thanks for this test. Glad to see it has the output filtering. Going to put one after my Flex 1500 to get 25 Watts to drive my Elecraft KPA500 to full power. Tried a different Chicom unit without filtering and it drove my KPA500 nuts.
Good luck with it Craig, thanks for watching 👍
Can you just do 20 but use the Hermes to generate the signal? (I am still gonna use mine) also, when you adjust the power down, to say 20w out, does it meet spec? Thanks Ape
It did at 30, I think I need to do a part deux 🤔
I wonder if there are a set of LPF Low Pass Filters in this unit. If not, perhaps you could just add one for the 20m band ? I suppose 17 meters should be checked.
I plan on doing more testing with it. It does have internal filtering, I suspect it needs to be tuned / adjusted.
Excellent ! The screen captures would have been awesome. I have had the same trouble getting them to save on a lot of this newer test equipment. Thanks for sharing !
Hey SC, I was pretty bent out of shape over the caps. Thanks for watching 👍
Thanks Ape, Kinda bummed about 20 but, solid info.
You and me both! Thanks for watching TJS.
Thanks for all the testing you do!!
Thanks Littrell, I enjoy it 👍
Good topic Ape. I am curious. I like using mine too. I think that power increase can be upgraded to causation, the evidence is far more direct than the statistical approaches that indicate a correlation. I am curious now about 12, 15, and 17M emissions. I will avoid using it on 20, this might mean the end of my idea of pairing it to a Hermes Lite.
Thanks LC. I’m planning to try some more testing, I’ll include those bands. Thanks 👍
At least it was just a turd on 20m and not a Smokin Turd. Nice video bro. Still a nice addition to the 705.
Thanks for checking it out Norrin...
It looked like there was a background spur on the same freq as the -39 on 20m. Spurs are not directly additive in dB, but will combine.
I have some more testing planned. Thanks for checking this one out Lee 👍
Off Topic: When you said, Big Azz Attenuator I fell out laughing and Yes it's definitely a Big Azz Attenuator. lol
Good info as always Ape. 73
It was a big ass attenuator! Thank for watching Adam 👍
Hello. Did you do a harmonics test for the OAX100 and the XPA125b amps? Thank you.
Sorry man, I have not
ok thanks. 73@@TheSmokinApe
Well, that's a shame as I was going to buy one...but good to know. Wonder if they're all like it, or if it's the usual lucky dip type scenario. What filtering do they run, out of interest?
It’s full of Low Pass filters, I’ll do a video on that part. I’m hoping I can find a schematic so I get possibly correct the filter.
Nice video. Is the SWR/power meter causing low level harmonics since there are detectors in it?
I suppose, but I doubt it...
Could you do something similar with a MicroPA-50 Amplifier? Thanks. Great channel.
I will see if I can get one 👍
Thanks. I've been hoping to see how the quality is on this.
I like everything about it, other than the results on 20m 😐
80 / 40M should be tested with a span of 50Mhz so you can see the harmonics better if there are any, a 500Mhz span doesn't give enough resolution at the low end. 20 and up a 100Mhz span is sufficient. On 20m look if you can reduce the drive and see what happens, you might just have a sweet spot in the input and overdrive the transistors slightly.
I did vary the power and frequency a bit on 20m and the harmonic persisted. I’m thinking there’s a problem with that particular filter. I’ll be releasing another video focusing on that.
Did you get a bad one?
Maybe it’s a good one?
@@TheSmokinApe 🤔😳
Was the 705 dirty on 20 meters? :)
Nope
This was the modded version?
Yes
Surely to be meaningful the test should show spectrum analyser results for both the input and the output. Also, the test needs to show the input power level. I did own one of these amplifiers and it was well within specifications ... PROVIDED it wasn't overdriven. These amplifiers are rated at 45 Watts maximum output but at that level they are really starting to become non-linear. Keep them under 40 Watts and they're fine.
I tested down to 30w, and it was still out of spec.
@@TheSmokinApe Mine was fine up to around 35 Watts. By 40 Watts it was starting to saturate and at 45 Watts it was saturating badly and was completely non-linear.
I suspect there’s some variation. There’s not a lot of quality control with these products so it can be a bit of a lottery.
That, I can agree with. Thanks for checking it out Andy.
Nice video
Thanks for checking it out 👍
Where does one buy a “ Big Ass” attenuator? 😊
I got it off ebay, do you want the link?
@@TheSmokinApe All good Ape, I was just admiring your wit.
@@HOAHamRadio lol
@@TheSmokinApe yes please
Run it through a tuner and you should get under 43dB no problem. 73 de WB4YDL
That’s a pretty good idea 🤔
3rd harmonic should increase 3dB for every 1dB increase in fundamental. So turning down the exciter should reduce the 3rd harmonic the same way. So perhaps a judicious reduction in power on that problematic band would be wise.
Thanks w5cdt, What we saw in the video on the 20m was the fundamental and next harmonic in the 10m band.
Pretty simple fix.
Cut a stub for 20 meter offending spur.
Problem solved, without redesigning the amplifier.
Thanks for the info Shane 👍
That is shame about 20m on that amp. I'm sure if any cause is isolated that you'll let us know.
I do plan on some more testing, it was pretty disappointing to see that on 20m.
Gas station amplifier?? ;)
Right.
Two comments.. the RF relay topology of those amps is crap .. they use the same relay for both in and out to the LPF selected. This sis guaranteed to cause problems but it's a cheap solution. You get blow-by within the relay.
Second.
It may be possible to jessy up the performance on 20 mtrs you need to find out what you have there in terms of L s and Cs measured not what's written on the body and not via an AL calc. Then run it through a Bessel filter program an find out where the break point is - some of the filters of that type when sold as stand alone (Ebay) are utter crap. they have never been checked for component tolerances. or were a bad design to start with . Rework it so the break point is sitting either ON 14.3 Mhz or say +20% if you want less power dilution.
THen build it with those components . You may with intelligent component selection be able to retain all coils on that band as wound and just pull around the filter by the filter capacitors of which there are likely three. Appn Note 267 from Motorola Is you friend but you won't know what Q has been the basis of the filter design. Everything in that appn note for a Network type B devolves from the selected Q. Nxp now appear to own the intellectual property of that AN.
any capacitors replaced have to have precisely the same technology as the existing ones. No Mylar green caps for example are acceptable.
TEF
Thanks for the detailed info TEF
Nice test method Ape! You probably have seen this already, but, you got me interested in learning more Sir! www.ccarc.org.au/wp-content/uploads/2020/11/MX_X50_Amp_blog_by_Peter_VK2EHQ.pdf 73 - KF6IF
Thanks for the info Phil, I actually saw it last night when I was trying to find the schematic for this thing.