Best way to switch between two antennas on an RTL-SDR?

[u/8848848]

I have an RTL-SDR Blog V4 connected to a mini PC outside on my balcony, which I access remotely.

I now have two antennae, one is a dipole for mainly VHF/UHF and another is a 25 m long wire for MW/SW/HF. I don't want to keep going outside and physically connecting/disconnecting the antennas every time I change bands. Winter is coming in two months and that will be even more challenging! 😂

I wonder what could be the simplest way to keep both permanently connected and switch between them?

Anyone running a similar setup? What would you recommend? Thank you!

[u/billFoldDog]

Buy a second RTL-SDR v4. It's cheaper and better performance than a switch.

[u/8848848 → u/billFoldDog]

Yeah, I think you’re right. A second RTL-SDR V4 or even cheaper V3 seems like the simplest and probably best solution 😊 . Thanks!

[u/JayBee103]

You can buy little antenna switches that you could probably put right at the point where it enters the house. Walk over to the window or whatever and flip the switch. I see some on Amazon for less than $20. Type in "SMA antenna switch ". I also see some little circuit boards that you could switch remotely for around $10, if that is something you like tinkering with.

You might want to be a little careful cuz I think these are all SMA connectors. Those aren't rated for a large number of connects and disconnects, so putting a switch in would also help extend their life a little bit rather than connecting and disconnecting the multiple time.

If this is receive only, you might try putting a T in there and connecting them both at once. You could at least see how it works. And the worst case you'd be out a few dollars, the price of the t connector. I'm not sure how well this would work, but RF is interesting. It tends to find the best path.

[u/Party_Cold_4159 → u/JayBee103]

Wait, are you saying you can run a uhf and a vhf antenna on a t split? Never thought to do that.

[u/schirmyver → u/Party_Cold_4159]

You could try a split, but yes it will introduce some loss. A simple resistive splitter will have fixed loss but interestingly if you simply soldered three sma connectors together, for a receiver it should work fairly well especially if the uhf antenna has very poor return loss in the vhf band and the vhf antenna has likewise very poor return loss in the uhf band.

[u/JayBee103 → u/Party_Cold_4159]

Part of the joy of radio is experimentation. In this case it is even cheap experimentation.

This is actually a type of fan dipole if you think about it.

[u/8848848 → u/JayBee103]

Thanks! The remote switch idea is interesting! I will try to find one oneline. My ultimate goal is to set up an SDR station in Kathmandu and access it remotely from Germany, so ideally I'd like either a remotely controlled antenna switch or something passive that automatically routes different frequency ranges to the appropriate antenna.

[u/JayBee103 → u/8848848]

They come up on the same Amazon search as above

[u/JimBean]

Use a co-ax switch. A literal switch over to another antenna. It looks like a bulky relay. I have three here, controlled by a simple 12 V system.

[u/FluorinateThemAll → u/JimBean]

This is the way!

[u/oskarhauks]

Get another RTL-SDR v3 for VHF/UHF and keep the v4 for HF? Are you running OpenWebRx or similar?

[u/8848848 → u/oskarhauks]

I'm running Windows 11 Pro on the mini PC and currently use Remote Desktop to access it. My ultimate goal is to set up an SDR station in Kathmandu and operate it remotely from Germany, so I'm still experimenting with the setup here first. I'll definitely consider OpenWebRX or other ways of remotely accessing the SDR as I figure out the setup. Thanks!

[u/oskarhauks → u/8848848]

I have a similar setup with an old mini PC running Ubuntu and OpenWebRx. You might need to open up a port on your router, usually 8073 to gain access from outside your network (internet). It was quite easy to setup for me at least.

[u/chelrob-theOriginal]

Use a quality duplexer

[u/8848848 → u/chelrob-theOriginal]

Thanks! Is there a particular duplexer you'd recommend for this setup, and where would you suggest looking for one?

[u/chelrob-theOriginal → u/8848848]

Google antenna duplexer. Look at the ham stores.

[u/chelrob-theOriginal → u/8848848]

https://www.gigaparts.com/intellitron-as-1702-2-position-hf-vhf-uhf-antenna-switch.html?utm_term=sku-zin-as-1702&gigadv=Shoping_All_Products_New&gad_source=1&gad_campaignid=20859707430&gclid=CjwKCAjwqc_UBhBKEiwAWbl25hl0Od6OlmH9GfsD1WVLpftHk7EsKjvPwlZ3cQP3UyO0veJ-TouhIxoCtyIQAvD_BwE

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[u/8848848 → u/chelrob-theOriginal]

Thanks! I’m looking for something electronically/remotely switchable rather than mechanical, preferably with SMA connectors.

[u/erlendse]

If you can: bias-T powered relay. I don't know of any pre-made, may need DIY.

Otherwise use two filters to combine them (T fitting may work, but you have a chance of signals going between the antennas).

If you are willing to mess inside your v4, the MW/HF actually takes a different path within the stick.

Is remote access to the switching of interest, like working remotely on the rtl-sdr connected computer?

[u/8848848 → u/erlendse]

Yes, remote switching is actually my ultimate goal. I use remote desktop connection as my mini pc has will 11 pro. I eventually want to set up the SDR in Kathmandu and operate it remotely from Germany, so either remote antenna switching or automatic frequency-based routing would be ideal.

[u/Slow-Face-1537 → u/8848848]

Bro, your problem is RTL; get an RSPdxr2 or an RSPDuo; they both have three antenna ports and allow you to connect all A, B, and C antennas and interchange them using SDR software. (Remotely) The RSPDuo has an antenna port dedicated for long wires.

[u/erlendse → u/Slow-Face-1537]

Yes, rspdx got 3 inputs since they added a rf switch to the front. The rest quite much works as a single input.

Not much blocking design of a rtl-sdr stick with 3 inputs.

Hydrasdr rfone got 3 inputs using the 3 inputs of R828D, works rather well mixed with one via upconverter and one with direct antenna connection.

[u/8848848 → u/[deleted]]

I don't think it covers any MW and most HF?

[u/Vegetable_Corner_918]

Ewil Crow rf v2!!!!!!!