Can These Cheap Ali Express Band Pass Filters Be Any Good??

We're Testing HF Band Pass Filters From Ali Express On The NanoVNA. They're Very Inexpensive But How Good Can They Be?
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[@jameski5oeb668]

I have the Butterworth BPFs made for winter field day this year. The ones from QST a few decades back don’t work QRO, they are designed to be place between the transceiver and the amplifier. Go read the for page instructions and you’ll understand what I had to learn the hard way over the weekend. They quickly saturate with heat at 100 watts SSB. Then the SWR curve won’t come down, similar to 100w FT8 into a 49:1 Toe Roid on an EFHW… so run power Mike just put the BPF between the radio and the AMP, then run 10w or so to the amp. Your mileage may vary! Good luck Mike!

[@krisraps]

I "Love" How You Say They Are "Cheap" For Me They Are Most Expensive Filters, I Don`t own One Because i Cant Afford One.

[@arnoldgrubbs2005]

Thanks for showing these, I had not thought to look on Ali. I wonder if you could do another vid and measure how many dB of rejection for the adjacent bands the filter has? Also the harmonic related bands, such as what you would see on your Rx on 7.1 MHz if someone was on 3.550 MHz? Again, thanks!

[@Screamingtut]

Mike, so tell me something, with say using the 20-meter bandpass, it will reject all frequencies but 20 meters? I'm I correct in saying that!!!. PS I love it when you say you don't know everything, put I try. I used to know all this stuff 30 yrs ago. but hitting 70 sometimes the mine goes wandering sometimes.

[@hamradiotube]

that is correct

[@dotemup_was_taken]

cool to see tom segura is a ham

[@PendejoRyan]

I get that a lot. Either Tom Segura or the cop from Stranger things. I don't know whether either or a compliment or an insult 😂

[@fyrearm]

Thanks for this video, been looking for other options for band-passes. Few of us like doing POTA together and this will help. I have a few ICE bandpass filters from RandL, they run about $74 and work. I might pick one of these up and see how they compare.

[@JonathanKayne]

I feel like bandpass filters are the type of thing that should be homebrewed. They are pretty simple to construct and make a great easy project for anyone. Plus there are tons of tools for designing filters on the Internet!

[@don_n5skt]

The pentaplexors and the old BPF that DX Engineering had were from Low Band Systems out of Europe. They do still exist and are selling on their website. I do have some of the ones from DXE but would love to pick up some others. Will check these out. Thanks.

[@va3hie]

Sounds good but I would like to know what the rejection is in db. If it's only 6 or 7 db of rejection, is that enough for what you want to do? More rejection is better. Not criticizing your work just wanting to know.

[@mikemcdonald5147]

guys look like twins with the bald heads and beards LOL thought you were gonna say im here with my brother. :)

[@franksouter3939]

Thanks for the recommendation. Just got mine delivered today. One question? Where is best to have it inline? Before swr meter or after it?

[@hamradiotube]

Not sure. I don't use an SWR meter. You'll have to experiment. I don't think it really maters though. I just put it close to my radio with a little 2' jumper and then out to the antenna.

[@franksouter3939]

@@hamradiotube thanks. i'll just have a play and see what works best. Cheers dude

[@technishn]

Look economically priced. I assume insertion losses were fractions of a dB. One could use a infrared thermometer to check temperature. The cases look like they are anodised. Hopefully the grounding is good.

[@KM4ACK]

Good info. Thanks Mike!

[@hamradiotube]

You bet!

[@eljam8138]

I think this is what i need for my HackRF SDR !

[@ReefMimic]

My manual for my clone hackrf recommends an external amplifier along with external bandpass filter and not to use the built in amp. Nooelec makes a 5 band bandpass filter I might try out

[@ReefMimic]

You also may want to consider a sma dc stop block to prevent external dc power from Lna going back into your hackrf/reciecer.

[@robertmeyer4744]

them some nice filters. 200 watt. should do 100 watt FT8 no problem . if you push too much power the ferrite heats up and SWR climes up just like ferrite does on antenna's. each person needs to have a filter for the band they want to use. 6 meters with 80,160 meters is far away may not bother each outher so much but depends on the radio rejection out of band. 73's

[@chriscoel]

Grabbed a 17M one, since there are billions of plans/instructions for the non-warc bands. These are easily half the price of even some of the cheaper ones. If they can isolate my diopole from the other guys BSP or Dipole.. I'll take it.

[@speedymartin2]

Thanks! Would be good to know how you use all filters at the same time on a multiband antenna using one transceiver. Is a lot of work to swap them out regularly. 73’ PD1MV

[@hamradiotube]

I literally just covered that on Monday's video. You need a Pentaplexer or Triplexer after the band pass filters.

[@pale_2111]

Do they make a multiband pass filter instead of buying filters for each band? Having to buy a bunch of filter and changing them at home or out in the field would suck. I like to band hop at home and having something like a multiband pass filter would help out a lot.

[@hamradiotube]

That would completely defeat the purpose of a band pass filter.

[@blugoose86]

Hey Mike, will you and your friend do a vid on the setting up the Nano to test these filters? I'm on a hard fixed income and can't afford to buy a set of these filters, even though they look amazing simple to build. I have a low pass filter that covers 10-80, has relays and diodes and controlled by Arduino. I'm not sure if I tested them right and want to make sure before I add the high pass portion. Thanks, and as usual, great video and solid information. de James KA9TII

[@carypeaden4147]

Very useful. Thanks.

[@wildbill1]

Awesome for that price going to have to order some

[@tonyreneeLaszlo]

What was the attenuation in dB? Not sure if you have the S11 log mag setup on the nano VNA. 73, W4BMX

[@PendejoRyan]

The blue line was the logmag

[@feeatlastfeeatlast5283]

Your measurements concentrated on the match (SWR). The purpose is to reject frequencies outside the passband, so how much DO they reject other bands? The data is right there on the nano but hard to see on the video.

[@PendejoRyan]

You are correct. We mentioned the blue LOGMAG signal on a couple of occasions during the video. I was actually looking at both the SWR and the LOGMAG to determine when the signal would be attenuated. Maybe if Mike has me on in the future and we do a more in depth look, we can explain it it more detail. It was a spur of the moment thing and I am not a KZbinr , so you'll have to forgive me. I tried to make the explanation as simple as I possibly could so someone unfamiliar with band pass filters could get a basic understanding on what is occurring.

[@nol_yaw]

I'm new so what does 7mhz filter mean? does it mean it just blocks 7mhz or is it 7mhz tooo something else?

[@hamradiotube]

Band pass filters block everything but the band they are made for. So a 7MHz bandpass filter would allow the 7MHz band to pass to your radio and filter out the rest. These are useful when operating with multiple people on different bands at the same place, like Field Day or a multi operator POTA activation, etc. Each station would have a band pass filter for the band they were on so they aren't interfered with by close stations on different bands.

[@yaobing-qw4rj]

Customized duplexers, filters, LC filters, power dividers, dual channel filters, design Negotiate prices based on indicators

[@Philip-KA4KOE]

Good stuff.

[@lhorschler]

Unapologetically Chinese lol, I love it

[@EvgeniX.]

yeah that was spot on!

[@EvgeniX.]

I doubt nanoVNA measures even any reliable, considering those filters rated to 200w (which I also doubt) they can behave Very differently under real load vs the few milliwatts at the test bench ❌

[@robc3863]

$40 is expensive for a passive bandpass filter, the parts cost unde $8

[@larrynathanson9892]

TWINS!

[@rayslinky]

haha, i was just wondering if one off aliexpress would be ok...

[@yuabonuga]

What about 1.5-30mhz one?

[@JonathanKayne]

That's what a low pass filter would be used for. If you wanted a 1.5-30MHz BPF you are basically wasting your money since it wouldn't do anything for you. These filters are useful for rejection of signals that would likely overload the front end of your transceiver. If you are operating on 20 meters and your friend is operating 40 meters a few dozen feet away then these are great.

[@pedrocatalan9814]

Twins?..

[@PendejoRyan]

If it was Twins, he's Danny DeVito and I'm Arnold Schwarzenegger.

[@hamradiotube]

See, he got the good stuff, I got the bad.

[@PendejoRyan]

​@@hamradiotubewait, are you saying I'm the shit leftover?

[@laszlokovacs8827]

Definitely not twins, but I'd bet they use the same barber.

[@startobytes]

40 and 50 bucks is not cheap tho

[@PaulReedy]

It is compared to the ones you'll find from most suppliers. Figure out what bands you'll be operating the most and start buying one here & there till you have a full set for the price of one name brand one.

[@LifeAtTerminalVelocity]

Why must you cost me money Mike??? Why?

[@bradkellison5359]

End fed antennas are only out of Phase if you butt the feed points and slope the end of the wire away from the feed point. like the letter V with feed points at the bottom.

[@hamradiotube]

I didn't say anything about phasing but they sure were interfering with each other.

[@blakepresent]

Thank you, Mike, another great video. Blake KB5RZM