Antennuating a cellular antenna

General Electronics
1

Ahoy anyone who knows more about antennas than I!

I am looking at testing some cellular modules and want to attenuate the signals in a controlled way. I have found some signal attenuators that appear to cover the frequency range necessary - does anyone know why they wouldn’t work to stick inline between the antenna and the module?

2

If you need a really precise attenuation, as always the equipment is bigger and more expensive. Using a cheap inline attenuator will work. Using multiple will attenuate the signal more, but is frowned-upon if you are really worried to maintain impedance (probably not a big issue for you). One other trick is to put the device in a metal filing cabinet and modulate how open the drawer is.

3

Can confirm the metal enclosure with precision operated radiation appeture works very well!

1 Like
4

thanks!

what i was looking at was this set: https://www.elfa.se/en/attenuator-set-50-ohm-rohde-schwarz-hz24/p/17636301?ext_cid=shgooaqsesv-Shopping-PerformanceMax-CSS&&cq_src=google_ads&cq_cmp=18208288444&cq_con=&cq_term=&cq_med=pla&cq_plac=&cq_net=x&cq_pos=&cq_plt=gp&gclsrc=aw.ds&gclid=Cj0KCQiA1NebBhDDARIsAANiDD1dMsO4XP0L4PhLJr7uQNlUxpdozdBsZlSVcNTrPSWp-MJc9sMN9yYaAp0NEALw_wcB&gclsrc=aw.ds

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accuracy is not a massive deal - i am really looking at qualitative response rather than quantitative (if i need the latter I do have access to a cellular test lab). This is for basic testing only - there will be a million other factors that will come into play to attenuate the signal and I will be really relying on the modems RSSI/RSSQ figures anyway and then attenuating and making relative measurements on various use cases.

so it sounds like this will probably do what I want it to do :slight_smile: thanks!

5

In this case these are probably massive overkill. Cheap Chinese attenuator are probably plenty good enough as long as they claim adequate frequency response. And yes, as long as the package shielding is adequate. Don’t expect a 40 dB attenuator to be accurate if your package leakage is 10 dB

Rich

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6

Yes, just get some cheap ones, save money. I work on antennas and networking stacks — but not usually transceivers. Mostly this is due to what I consider to be a mature market for commoditized transceivers available to buy, which the manufacturer tests instead of me. Anyway, for what I do, cheap attenuators virtually always are sufficient for testing the network in different attenuation levels. For antenna work I don’t use attenuation at all.

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