Cheap 2 way SMA splitter boards

[Clubba]

https://www.amazon.co.uk/gp/product/B07LFYJP66

[Anmer]

Be interested to see how well that performs?

[Clubba]

Well at less than a fiver for 2 I'll let you know 
They are UK stock BTW

[Clubba]

Boards arrived today (48 hrs with amazon Prime).
They are ok and function just as well as the Y cables, there is no electrical resistance in the circuit and no noticeable loss in signal. There is enough room to connect 2 SDRs with a double male connector on each unit.
10/10 from me 
Going to get a few more now before they sell out.

[Anmer]

I always found Y-splitters caused a loss of signal.  Have you tested with a more expensive splitter?  Such as a Mini Circuit or RF Systems SP1?

[rikgale]

Each time you split the signal you loose -3db of signal + the insertion loss of the item you are using to split. The more expensive items have very low insertion losses... cheaper items will probably have a higher insertion loss. Only split if really need to.

If you really want to split the other thing you can look at would be a multicoupler, which is capable of splitting the signal without the loss of splitting, so all you then have to handle is the insertion loss. I use one for my VHF antenna and have 5 outs. These are not cheap, but neither is a good quality splitter of the likes that Anmer suggested.

[Anmer]

These are not cheap, but neither is a good quality splitter of the likes that Anmer suggested.

I got my "pre-loved" Mini Circuit splitters off ebay, shipped from the USA.  Couldn't notice any loss of coverage or range.  But it's important to check thje frequency of the splitter as they vary a lot.

[Clubba]

The bandwidth on these cheapo splitters is rated at 100-2700mhz but I'd take that with a pinch of salt. It's quite possible they were designed as 2.4ghz splitters but they do work without any noticeable loss on VHF airband and they are 1/3rd the cost of a Y cable on Amazon.
The SMD on the board is a 100ohm resistor.

To be honest guys I see no noticeable difference in signal reception between a direct coax connection and a low cost splitter for RX (I have done 1090 coverage tests). Alas I no longer have means of testing the RF incoming to be precise about any loss or gain and I doubt I'd see much fluctuation on the antiquated scope I own, nor do I have a probe small enough for sub-mini components.

As there is no RF power going out the theoretical -3db loss really is negligible and I really don't see the need for a more expensive splitter. No matter how much you pay for a splitter the theoretical loss is the same 2x=-3db 4x=-10db depending on design ofc, if you can reduce that loss by 0.5/1db for a lot more money you need to ask is it really worth it and I don't think it is in a non-competitive receive only set up.

I'm using a single Airnav antenna which needs to be split for use on VHF and 1090 as does any multiband colinear for simultaneous multiband use. The loss is to be expected and countered by raising the antenna height in my experience. The VHF signals do vary according to conditions as can be expected and I'm getting 300km+ coverage on 1090, current best 1090 is South at 343km @39000ft and have even rx 1 confirmed flight North on 1090 at 1600km+ @40000ft (most likely ducting or reflection)ZZ665 13 July 8.02am local time. I do well for my location.
I'm using an RSP1a for VHF no LNA, and  FA pro+ stick for 1090 no additional LNA.
Height 153m ASL + 7m for current mast height.
I've used a Y splitter from day 1 of using virtual radar.
I think the filters in Both SDRs are adequate enough to keep any IF interference at bay as I'm not seeing any interference on either.

However if I were transmitting in the microwave bands that -3db would be a very different matter and due to the low tx powers I've used I wouldn't entertain splitting or using a coax relay switch and would choose separate antennas every time and have done so in the past.

I do intend to build and test dedicated band antennas at some stage, health & WX permitting.

[Clubba]

I've been keeping my eye on the distances most of the night and I'm still pulling in adsb sigs from 335km, I'm happy with that result.

I forgot to add to my earlier comment that I wouldn't use a cheap splitter like this if I wanted to monitor 2 signals on the same band because the losses could be infinite without an inductor to balance the circuit, line isolation would be more of a factor too and I certainly would not recommend using an LNA  with such a basic splitter.

For me these cheap splitters are good for a few experiments I want to try on 1090 but that's a very different topic in the making.

[Clubba]

Final tests complete and they bolster your claims guys.

With one of these splitters in-line the loss of ADS-B aircraft on screen at my location is between 10-15 compared to a direct antenna connection.
The aircraft that I lose after each swap are at lower altitudes (less than 10,000ft).

[Clubba]

I have tested these splitters using a VNA and if I've done it correctly the insertion loss is 3.71db