2.4 GHz Data Throughput Issue

Thread Starter


Joined Sep 15, 2020
I am working on a project with an RSL10 2.4 GHz radio. I'm far from an RF or antenna expert, but I have worked with radios in the past (both 2.4 and 1 GHz). The RSL10 is definitely the worst of the bunch as far as support, documentation, and functionality goes, so I'm kind of groping around in the dark. I'm sending raw data from one radio to another on a not very popular channel. Everything was working OK except I was only receiving about 90-95% of the packets I transmitted, which is pretty low in my experience since the radios are sitting right next to each other on a bench. After much messing around, I discovered that if I sent a dummy packet, or even just one byte, very shortly before I send the packet, my successful packet transmission rate goes up over 99%. What I can't figure out is whether this is some strange issue with the RSL10 (which wouldn't be hard to believe), or is there some physical reason related to RF communication that would improve communication after sending a byte or two. Like maybe it drives nearby frequency hopping devices off that channel. Or something to do with the carrier frequency maybe.

Is there some physical, RF-related reason why sending a short amount of data immediately before transmitting a packet would make the packet more likely to be received?

Edit: Sorry, the title of the post should say "throughput" not "throughout." Unfortunately, it doesn't look like I can edit the title, or delete the post. Moderator, can you help me out?

Moderators note : changed title.
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Joined Apr 7, 2016
This could sound like synchronization issues - something that the modules is using a too short preamble sequence when activating transmission.

I would try to move the two modules physically a few meters away from each other, to see if the two receivers have it easier with less maximum signal in the connecting phase.


Joined Feb 24, 2006
There is another phenomena that might be at work here and it is called "receiver desensitization". In the presence of an RF carrier that is too strong, even if it is on a frequency outside the receivers passband, it can make the receiver go deaf. That is why moving them some distance apart might be a useful thing to do. I'm less certain about the short preamble burst because I'm not familiar with that protocol. The best you can hope for is that it brings the receiver VCO back closer to the transmitters VCO. I can't see a sync lock followed by a gap followed by a normal packet being a good thing for the digital part of the receiver. Maybe it is enough to set the receiver's AGC level. This is all rank speculation, but good luck finding a solution.


Thread Starter


Joined Sep 15, 2020
Thanks for the thoughtful answers everyone.

I tried making the preamble longer, but that didn't seem to fix the issue. I also tried turning down the transmit power, and that also didn't seem to change things. One of the other engineers I'm working with suggested we try connecting the antennas together (with the appropriate coupling hardware of course). Then we can know for sure if it is something to do with the RSL10, which I'm starting to think is the case, or something RF related. Unfortunately, neither of us have time to work on this right now, but if I discover anything more about the issue I'll post what I find here.