ONE ANTENNA - FOUR RECEIVERS RF ACTIVE DISTRIBUTION

Here we take a look at a cheap solution to sharing one antenna with up to 4 different receivers.
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[@Jonnyweareten]

It would be nice to see you comparing between using a regular splitter and using the active distribution.

[@excossack]

That would be interesting to see a comparison between active and none active splitter. I was thinking of building a splitter but one of these might do the job.

[@roblutz8931]

A two way splitter has about 3.5db loss or 50% signal loss on each port, you probably won’t see much loss until your looking at weak signals. With a 4 way splitter, it’s closer to 7 db loss or about 25% of the original signal on each port. Add in coax loss from the antenna and you could easily see 9-10db loss or 12% of the original signal. For close in stations you will be ok but it will not be pretty or usable for distant or weka signal stations.

[@n1vca]

Dear Matt, I instantly noticed that you are all clogged up ... get better soon. Thanks very much for the intro to this active splitter. I ordered this and the high impedance preamp little over a week ago and a few days later got the message that it is currently unavailable and if I want my money back, I declined the money back offer and they mentioned it was supposed to be back in stock on the 6th. But so far it hasn't been shipped yet ... may take a little longer I guess, it is definitely a bargain. It looks pretty good inside, with the transformer on the front end. What surprises me what kind of an low gain wideband IC they are using ... it looks like they may simply use the same impedance converter amp from your last video, which maybe is just a low noise voltage follower circuit, where they define the overall gain with the input transformer and then for better output isolation run the same IC(amp) on each channel. The isolation between the outputs with two reverse amps in line should be pretty good. Usually splitting a signal into 4 under ideal electrical conditions you loose at least 6dB (3dB on each split), which has to be compensated in the preamp (possible source for intermod), but here with the voltage to current follower on each output you don't need as much amplification in the first stage ... this thing might be pretty good/amazing for its price. I built a similar HF splitting amp myself, using a J310 based high dynamic push-pull preamp and a cheap 75 Ohm TV/Sat splitter behind it (gets bad below 1MHz) ... works great on 50 Ohm as well ... even today with this unit in line and a wideband loop as antenna in the attic receiving planes locations on HFDL (17.9 MHz) overhead Australia here in Munich, FT8 from all continents at the same time in the afternoon on 18 MHz ... no intermod ... but this device you introduced might also be good and ultra portable with the built in battery.

[@allancopland1768]

Interesting and useful. Such things used to be very expensive because they were never made in large numbers.

[@electronics.unmessed]

👍👍👍Thanks a lot for that comprehensive test!

[@TechMindsOfficial]

My pleasure!

[@shizzle666440]

This is ideal inconjuction with sdrtrunk great find.

[@allenshepard7992]

Four channels looked like overkill at first, but then its good to see when the lower bands open up and if there is a QSO to be made. Even listening to NOAA in the background would be good.

[@fotografm]

Interesting device ! I wonder what the linearity and noise figure is like ? Strong signal performance may also be an issue with such active devices. I currently use passive splitters comprising resistors which works from DC to some GHz.

[@BradSnyder1]

Very neat distribution box. Thanks for sharing it with us. 73

[@dennis8196]

Small UK vendor Cross Country Wireless has been selling these for years, extremely good spec, really well made and they can do custom builds for specific applications. Buy from them instead of from China. The warranty is better, the spec is better, and you will not be disappointed.

[@darrellhagan6124]

The CCW unit costs UK 191.00, USD $239.94+ shipping. No doubt good quality etc. but just too much money.....

[@explodinglemur]

I've got a 1-to-8 Stridsberg VHF/UHF multicoupler. Pricey but high quality. I'll have to grab one of these and compare it to the Stridsberg as well as an off-the-shelf unity gain TV distribution amplifier.

[@AceBlaggard]

That's would be a useful comparison, likewise I've got a CrossCountryWireless VHF/UHF multicoupler so I might get one myself to see how they compare. I wonder if anyone has done a technical review on these?

[@d.shortwave4280]

@@AceBlaggard please let us know... !

[@johnboutin8770]

I have one of these on order and would love to do this, but I have yet to find an understandable video on changing the serial numbers on the dongles. I hear you have to do this to use more than one at a time. Thanks so much for your wonderful videos.

[@nethoncho]

Thanks for sharing your videos

[@TechMindsOfficial]

Thank you very much 🙏

[@petewright2283]

Shame it’s not got more range. Is the battery soldered in? What’s the loss across the ports. I need a few of these for my SDR server.

[@PaulGrayUK]

What's the RF quality like when running from USB over just a battery?

[@Imaboss8ball]

Probably would be great for a listening post that scans various frequencies and record/decodes any transmissions.

[@JarkkoHautakorpi]

Could those narrow band RTL SDR be linked/combined to create one wide band receiver, into one waterfall view? HackRF has nice 20MHz bandwidth, but it's expensive.

[@SkibidiWaPaPaPaPa]

wow nice find, thanks

[@TechMindsOfficial]

Thanks for watching!

[@dhiflixmvteam4468]

Can you check the signal level of sdr v3 and v4 using this with same frequency

[@TheGreatGastronaut]

Depending upon the application, it’s probably of more importance that the active splitter increases the noise floor more significantly than the gain it provides, meaning weak signals will become buried in the mud that the splitter creates. Combine that effect with the -6dB ‘gain’ (minimum) that the split imposes and an additional affect of intermod products occurring within the band of interest due to strong out of band signals interacting with the splitter’s amplifier and the overall outcome is poor. One can obtain very high quality surplus splitters from fleabay for a low price. They are wideband, have flat in-band response and a real 6dB split. These devices will easily outperform an inexpensive so-called active splitter.

[@earlyadapter643]

These isolating distributors are typically used for clock distribution from a GPSDO output, but i never really understood how important the isolation aspect actually is. Anyway if its price range stays close to that of a non-isolating amplifier/splitter, for sure it wont hurt to use this instead.

[@hauptuhrdotnetblog6700]

The isolation is to stop the LOs from each receiver getting into the front ends of each other's.

[@EduardBaba]

Mind if I ask what type of antenna do you use for this? It appears rather very capable.

[@BillRicker]

But can they share/sync LO , so that all 8 I/Q are phase comparable?

[@RadioRestoration]

I have just received one of these. It works ok on battery, but if switched on and plugged in to a 5v source, the internal Lithium battery control chip causes noticeable RF interference on the output ports. Not really a problem unless 24/7 operation is needed as the unit can be charged between operating sessions and the supply disconnected when in use. If continuous operation is a must, then some hacking with a linear DC supply may be needed

[@ruidelgado5294]

Would it be a problem if you use it with a LNA/SDR (Nooelec Smartee/ LANA) combination? I'm afraid that the voltage from the LNA can damage the other 3 SDR, if even possible. Anyone please comment.

[@MarkPentler]

Good for trunk tracking

[@PowderMill]

FINALLY… USB-C ! I can’t wait until ALL manufacturers ditch Micro-USB. This looks great for use w/ multiple SDR receivers. I just wish it could go up to T-Band UHF (520Mhz) it would make a nice addition to a Broadcastify streaming radio service provider’s toolbox. Thank you.

[@ilantsameret3927]

It would be nice to have it with a built in preamp... i wonder, is there a gain loss each time you add a receiver?

[@johntyler4222]

Interesting demonstration of how not to connect an sma connector 😉

[@MultiPetercool]

I have an SDR V4 & SDR++ on an older MacBook with a 2.3GHz Dual-Core Intel i5. Is this enough horsepower for four SDRs??

[@_droid]

Just a small note. You shouldn't spin then device when connecting SMA connectors. Only the cap should be turned as it's designed. Otherwise you risk damaging the center conductors as they are not meant to be spun around against each other.

[@teotwaki]

I couldn't find any tech info online. What is the overall gain or loss from input to output? How about isolation between ports? Reverse isolation from output to input? Power consumption?

[@TechMindsOfficial]

The only specs that I could find documented are on the product listing, which is linked in the video.

[@tvcomm1]

Thanks for the review. I usually find your reviews useful, but why not do a proper objective test of signal strength and noise between the antenna and receivers firstly direct (ie NOT via the device) followed by comparative tests via the device? Lay out the results in a table so that we can make a definitive decision on whether it's worth buying? Thank you.

[@TechMindsOfficial]

Simply because for that I would need a calibrated signal source that was the same for each test. Using SSB has too many variables, signal strength, propagation etc. The insertion loss of this product was not really a topic for this video. Cheers

[@tvcomm1]

Having now bought this device, I conclude that it performs terribly on the HF bands. I actually bought two and the 2nd one is the same, which excludes a fault in one device. The VHF bands seem ok from 60 upto ~250 MHz and I use one to split my discone to several receivers. On HF I was using a passive splitter to feed an RX888 and and Airspy HF+ and the response on both devices was fairly flat. When I inserted the DA in its place, the response is all over the place and there are several bands that are rendered unusable due to blocks of noise several MHz wide - and I am using a low pass filter (passes below 40 MHz).

[@TheElectronicDilettante]

Is there any way of hacking it to change direction? Essentially to work like an ant. switch , like HackRF’s OperaCake( multiple antennae to one Rx). That would be cool. Thanks for the video!

[@OctavMandru]

It's not possible, being an active device. It amplifies broadband and then splits it into 4 so no combining possible

[@erlendse]

There is a lot you would need to change. Way easier to get a different device, even build your own. Looks like there are 5 amplifiers in it, and they are all directional. So wire around power pins and rotate components, figure out how to make the combiner work due to unexpected problems e.t.c.

[@CheapSushi]

It's expensive but the Kerberos SDR does this and I believe it's the cheapest one that makes sure the timings are the same.

[@JohnBaxendale]

That's very handy, there's only so much space on the roof! One question would be can you remove the battery and just power it direct from USB-C?

[@TechMindsOfficial]

I guess you could, I dont see any reason not too. In fact it was one of my questions to myself as I know some people like to remote mount SDRs in the loft, or in cabinets etc.

[@JohnBaxendale]

@@TechMindsOfficial Yup, exactly my use case, all the SDR stuff is in a loft that’s fairly well insulated from electrical interference!

[@DonzLockz]

Awesome, its a poor mans Flex slice receiver.👍🤠

[@djcobylevy]

What is the LNA used here? 501N

[@TechMindsOfficial]

Ummmm.. There is no dedicated LNA used in this video, it's just the distribution box. :-)

[@rickkowalewski664]

@@TechMindsOfficial There are 5 amps. 501Mt are the IC's in mine.

[@n1kkri]

can you buy the V4 SDR RTL anywhere?

[@michaelmarcus9005]

Available from both Amazon, and the Manufacturer SDR-RTL V4 blog.

[@n1kkri]

@@michaelmarcus9005 I'll take a look. Last couple time I looked they were always out of stock.

[@shamrock1961]

I live in the states. The best they can for shipping it to me is Jan 2024. $40 usd gets me to December 27th. The device costs $25 USD to purchase before shipping 😮

[@michaelmarcus9005]

Purchased one from AliExpress 2 weeks ago for $16 plus free shipping. It's due to arrive today. The price did increase a couple dollars since I ordered, but still a deal. KG7M Portland, Oregon

[@frankfoduw-ci8rr]

SWL contest 2023 is started, you are welcome

[@bluegizmo1983]

If your just doing receive only, why can't you just use a few sma splitters?? Then you should get full bandwidth instead of being limited to 300mhz...

[@mstrickk1]

Don't twist devices onto antenna cables. The threaded section of the cable spins for a reason. If you spin the male pin inside a connector, the connecting tabs inside the connector scrape the male pin. Even doing this just once can create a bad connection by increasing resistance, or outright make it fail once fully tight.

[@TechMindsOfficial]

That's a good thought! Although never had an issue is 30 years of radio.

[@mstrickk1]

@@TechMindsOfficial Radio components for the most part are better quality than what I've worked with for the last decade, but there are still some connections you have to be careful with. I have a few 239 90 degree connectors that are bad. Mostly coated ones. In the communications industry(cable, internet, phone) all the wires and a lot of splitters grounds etc. are copper coated pot metal.

[@W8RIT1]

I'll take a stab at one, but I really want one for usage for 800 MHz trunking for listening to different simulcast systems.

[@anonymous_friend]

Who uses 800mhz trunking? New to this topic, seems fascinating.

[@zerobow9413]

Nice but SDR`s having no real front ends I like to use low noise LNA`s and filters per SDR

[@TechMindsOfficial]

you can still use LNA and filters, between the box and the sdr.

[@rohnkd4hct260]

If it just covered up to at least 400 MHz.

[@nandrews8412]

No need to use active distribution as loss is negligible on a passive 4 way splitter. And a plus no battery to go bad and no distortion insertion from the power supply.

[@explodinglemur]

At least 6dB down...

[@XBKLYN]

4-ways have 6dB loss and limited bandwidth

[@Oreomeister]

If they find a way to open these up to maybe 1kMhz, I'd gladly pay considerably more.

[@KuehncIncorporated]

1 EFHW = 4 WSPR

[@handlesRtrash354]

this is rad and all, but WHERE ARE THE GOSH DARN DRIVERS FOR THE THING (i am losing my mind)

[@Martock1017]

No drivers necessary as it is only an amplifier and could be used with 4 standalone receivers which don't require a computer to function.

[@vicrod74]

Why not make one device that can do all four?? 🙄

[@AdrianBoyko]

Better font, terrible kerning

[@TechMindsOfficial]

If you're referring to the thumbnail, it was done on purpose..

[@AdrianBoyko]

@@TechMindsOfficial I’m actually referring to the lettering on the unit itself. They didn’t use that terrible font they so often do on products from that part of the world.

[@RadioRich100]

SDRs are junk

[@stampededestroyerxx2845]

so u are the reason why the v4 is sold out 😠

[@MdmKamen]

😂😂

[@GamingAmbienceLive]

4 girls 1 cup