CHEAP HF RF POWER AMPLIFIER - OGS-50W

Here we take a look at the OGS-50W HF Amplifier. A very cheap HF amplifier suitable for QRP radios.
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[@Lastaii]

Interesting, what were the harmonics like? For instance, without a low pass filter, I'd expect a transmission on 7.104 to be heard on 14.208 (and other multiples) as well...

[@JacobNewmen]

Chinese garbage

[@richardchambless12]

A big bag of spare IRF530s needs to be included with this amp. I’ve had tons of trouble with a similar design sold on ebay. These non-rf mosfets can fail easily if overdriven or mis-biased.

[@colinmcdonald7591]

You weren't seeing anywhere near the rated output likely due to the fact you were running the amplifier at 12V instead of the rated 13.8V. 2 volts can make the difference. Also I wonder how much RF input the amplifier can handle before you see the final transistors plateau or over saturate. Did you check for output on 10M? No LPF so it should go higher without trouble. Also audio got very distorted in the SDR tests, though that could have something to do with under voltage to the amp. It certainly wasn't overloading the sdr as that is a completely different kind of sound. Neat stuff. Run it at 13.8VDC and it would make for a nice extra 3 or 4DB on a qrp radios output signal.

[@StayFrostyr]

I put one of these on the spectrum analyzer. Third order harmonics were only 11db below the fundamental. These are not legal to use without an appropriate LPF between the amp and the antenna.

[@alexanderleon2465]

Thank you for the video review. I have one and just used it yesterday. I used it with my xiegu g1m puts out 5watts and called out on 20m and got a response saying I was overdriving it and ruining the band. I dropped to 1watt input and was told it was still way overdriven and now I wasnt understandable. I imagine for CW it'd be great but so far with SSB I've had issues. Any advice is appreciated

[@billryland6199]

There is no low pass filtering. This is not really operating as a linear amp. These should not be used on any ham band.

[@alexanderleon2465]

@@billryland6199 after using it and spending time with an individual trying to get it to "not blow up the band" I understand what you are saying

[@syfr]

Splattermatic cheap unfiltered amp

[@Jonnyweareten]

great video as always. how many watts would you need to input in order to get the full 50watts output?

[@Randrew]

From the measurements shown here, I suspect you'd only get the full 50W at 80 meters with 5W input drive. I don't think you'd get to 50W on the other bands with 5W in and I'd be cautious of trying more than 5W input. Chances are the PA's input (matching) resistors won't cope with more. Heck, they may not even cope with 5W input continuous on digital modes like WSPR. That's just me guessing since I don't have one to check out.

[@migalito1955]

I bought an OGS-50W before I saw the videos that dislike it. I figured they abused the amp, thus their issues. To be safe I used a 40 meter resonate antenna. I also used my bitx-40, but since at 13.8 volts with adequate amps it puts out around 7 watts I decided to try running the bitx-40 at 9 volts with at most 2 amps. This brought my rigs power down to 0.8 watts on my crappy meter, but the combination of an input of 0.8 watts and the OGS-50worked great. I'd say my meter suggested 28 watts. The only issue is the recieve to transmit relay has a delay of about 200 miliseconds. I spoof this by tapping the mic before starting my audio. On digital modes this could be an issue but I really bought it for giving more kick to my Qrp kit SSB rigs.

[@siffler1234]

just an update, these work quite well, no affect to audio and good reports so far.

[@perhansen8170]

Great video! 73 from Norway

[@mikev333]

Will it work with QRP Labs QDX for FT8?

[@Davidm-M0TPT]

What a great bit of kit, nice one matey

[@bob_mosavo]

Thanks 😁

[@combatwombat71]

Can you insert the words 'and nasty' between 'cheap' and 'HF' in your video title? HI. Interesting review though. 73.

[@sk718serg]

Жесть... 🤪

[@K4AX]

You need to look at the harmonics, second and third order especially, that's what bandpass filtering is for.

[@Yosemite_Sam]

No LPF on output. Unusable in this configuration. People will still buy it and use it. Cheap low powered rubbish that doesn't seem to make even 50w. Needs 13.8v too.

[@R2AUK]

Thanks for the review. However you can't measure the power output without using an LPF. Your power meter will count all the harmonics as well.

[@wf2v]

No LPF? Stay away from this one!

[@Randrew]

Depends on your purposes. As Matt said at 0:45 "this is what you could call an experimenter's item". Buying stuff, powering it up and getting straight on the air is a great part of the hobby/service... but that's not all there is.

[@syfr]

This is irresponsible for amateur service without output filtering.

[@OE5JFE]

The important question is: Where is the Low-pass filter? I did not spot any on the PCB. They were even to lazy to connect the high SWR warning LED. Pretty sure if you look at the spectrum analyser you will find high level harmonics. So please don't put this on the bands before checking. Even the cheap MX-P50M amp has switchable LPF. 73 from OE5JFE

[@johnr2391]

yeah yeah we know. No lpf... obviously for a cheap china amp. Same story since the 70's ....... we know, we know.....

[@nbookie]

Did you even watch the video?

[@DBruno]

Just curious if there is a way to add external low pass filters to an amp like this? I realize it's not a good, high quality amp but was just curious in general.

[@Flagrazi]

It's hidden

[@stevenhershman2660]

If you look at the product and compare it to the advertised CB amps ( you will see these when you look up the Amp in the video) they are very similar : no swr protection, no bandpass filters, similar price.

[@Randrew]

You buy the cheap, weird stuff so we don't have to! (though we might anyway)

[@remiechange5482]

LOw cost design . Exist due to new MOSFET with low RDSON used in switched power supply : Low cost transistor with thermal unstability with Vgs difficult to adjust. I burn many in this kind of kit. First stage is not wide band. Power output is not flat. very bad harmonics. No low pass filter. Low cost , but too expensive for results. I suggest not loose time with this and prefer more expensive, lower power outut kit, flat response. QRP labs are more serious. I will purchase one.

[@kikodv1ksantos936]

any chance you can test on digi modes? Ft8? JS8? PSK31? RTTY? Thanks! DV1K 73

[@brucewolfeki6bsl840]

Using on IC-705 with dummy load and same 3 watts produced over 40 watts. Why did your testing not output over 30w?

[@sreekumarg]

Dear Any such cheap amp having 250 watts output ? Can you do a review ?

[@davecurry8305]

No filters. Beware!

[@AliReza-zx8km]

Nice... ... ... ...

[@dmsungam]

Any thoughts on which Android tv box to root/use for ham radio purposes? X96 Air/x98 another? Could be a good video. Great channel!

[@TechMindsOfficial]

Ive been thinking about this myself. As soon as I find something I'll make a video. Cheers

[@stevecarlisle3323]

So many of these products generate many questions. Its not much good if they go un answered.

[@ohaya1]

Great demonstration! I love these practical tests, thank you!

[@rodneyhodge652]

What transistors/mosfet dose it have ?

[@L8errore8robot]

Have you tested It with a 5w input?

[@dl4xt]

I have already this AMP. works very fine. in CW the Automatic RX/TX works not perfect, but usable!! it works fine with the uSDX+ V2 and its in the same case btw. 73, Jan DL4XT

[@PhilinWaterloo]

Can you tell us the power output with the usdx-v2 and the supply voltage on the amp?

[@dl4xt]

It's 10db gain. 3-> 30w 5-> 50w The USDX has different output power on the bands. You can watch mat's video from the USDX and add 10db

[@siffler1234]

you've done it again matt, i have one of these on route, so pleased when you do a review of this area of the hobby mate keep it up 👍👍👍👍

[@j204ever5]

Scrap!!!

[@tomsworkshop5856]

Judging by your power output, you've already sent one of your finals to heaven. Mine gets 50 or more watts on all bands, with 2.5 watts in. :) I say this, because it is very sensitive on 80 meters, and I can't input more than 1 watt in before it goes over 70 out.

[@allenshepard7992]

Thank you for the video. The sticker shock of HAM equipment is daunting. It looks like a $700 to 1,800 hobby to start with thousands more depending on the band. With people talking of 700W to 1,500 watt output, meaning much more input, seeing a simple 50W new unit is nice. Makes it look affordable.

[@W4TRI]

Lost me at that cheap power cable/connector. Not even finishing the video on this one. Send that junk back!

[@K4AX]

It's a variant of a dean's connector. They are pretty popular with RC stuff with high amperage. Kind of the RC equivalent of the Anderson power pole for ham radio.

[@ruffdog272]

@@K4AX it's an xt-60 connector

[@Randrew]

Do you have ANY gear that doesn't have a crusty, trusty brand name on it?

[@gliderrider]

Would have liked to seen a cw test.