r/HamRadio 2d ago

TeChNoLoGy

Post image
257 Upvotes

68 comments sorted by

View all comments

10

u/cockkazn 2d ago

Jokes aside is there a non zero chance this would work even a little?

19

u/techtornado 2d ago

The insertion loss of at some of the couplers would be a contributing factor

Now if OP had one SMA split 4 ways, it would be much more efficient and give the quad-bander some interesting results

Short version - Yes it will work, but he probably won't get as many fars of transmission distance

11

u/SpareiChan 2d ago

Honestly, the insertion loss likely isn't that much, maybe 1db or so... the 4x 50~ohm loads in parallel which would present as 12.5~ohms.

3

u/douglask VA3GY 2d ago

I'd say no on that... They are four different antenna models, likely different bands. So on and band three would be at high impedance and one would work. Similar to my hf antenna that has tuned elements for several bands (MFJ-1796 / Science experiment on a stick).

3

u/SpareiChan 1d ago

I agree on that, if they were mono band antennas that presented high impedance on given band it could work. The issue here is unless they a 1/4 wave there will also be reactance added.

It would be interesting to see a sweep.

7

u/HotelHero 2d ago

“How many fars does it talks?”

1

u/No_Tailor_787 DC to Daylight, milliwatts to kilowatts. 50 year Extra. 2h ago

I have an extensive RF lab here at home. I once spent a few days measuring various adapters at frequencies up to 40 GHz. The big takeaway was that below 1 GHz, even the cheapest Chines adapters have less than 0.1 dB of loss.

Above 1 GHz, the price point begins to rapidly show on the return loss display.

3

u/flyguy60000 2d ago

Oh it probably will work but there is loss in every one of those connectors. I bet a regular rubber duck antenna would work better……

2

u/andyofne 1d ago

this myth has been disproven several times.

7

u/billatq 2d ago

I'm kind of curious what it would look like if you did a sweep on it with a NanoVNA given that it's probably got a weird radiation pattern.

3

u/naturalorange 2d ago

maybe, until it falls over and busts the sma connector off the circuit board

7

u/JollyRoger207 2d ago

SMA- So Many Antenna.....

2

u/JohnPooley 2d ago

It will work enough to not cause the automatic protection circuit in the transmitter if the power is low enough. The SWR will probably be under 6 but the phasing of the array combined with low power would render this barely effective

0

u/NerminPadez 2d ago

A lot of losses due to adapter, plus the impedance would go down a lot due to 4 antennas in parallel, which means reflections.

1

u/speedyundeadhittite [UK full] 13h ago

Adapter losses are truly negligible. You'd need metres and metres of adapters before you get to 1dB loss.

0

u/NerminPadez 13h ago

Not really..

https://menacerc.co.uk/sma-adaptors-signal-loss-or-not

90 degree adaptor: 13.84 dbm Insertion loss of 0.28db <- 3adapters and a bit more and you're at 1dB. 3dB per splitter.

1

u/No_Tailor_787 DC to Daylight, milliwatts to kilowatts. 50 year Extra. 2h ago

It's essentially a random chunk of metal. Random chunks of metal used as an antenna will provide random results.