A couple of thoughts, in no particular order of relevance:
- You may be running into multipathing beyond what the Shari can handle. I haven't looked too much into the SA818 filtering algorithms, but I've run into this in the past on ISM devices (in and around 433MHz).
- Antenna resonance is more an issue on RX vs. TX. How was RX resonance when you attached the VNA? Was it a nanoVNA or pro gear?
- Is there a distance where it picks up the signal again? At these frequencies, you shouldn't be experiencing destructive interference that broad, but I've seen weirder stuff from RF.?
None of these are Shari-specific, and may well have nothing to do with the issue at hand. Just the first thoughts in my brain.?
Do you have access to an rtl-sdr or similar? That would be an easy, low cost way for your brother to investigate the issue.?
You can use the antenna from the Shari and software like gqrx or sdr# to look at what the incoming signal looks like. If it isn't nice and sharp like?, the problem
exists with his signal. If the signal does look similar, the problem likely exists within the SA818.?
Hope that helps!
Kevin
AD7KM
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On Jul 27, 2022, at 17:58, KB9WOO via groups.io <kb9woo@...> wrote:
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So, I built my brother a shari and it's linked to mine pretty much 24/7.? We usually chat while he walks the dog, etc.? Our experience with the range he has is kind of confusing and I'm looking for ideas from you all of what we should be looking at. Here's
our experience:
Once he gets a certain distance from his house, in any direction, his Shari starts dropping out. The weird thing is his signal is very strong into the Shari and he has no issue receiving my signal from his Shari. Our last test was in a new direction, and when
referencing a map, it's only about 500' from his house.? It seems to be about 500' in any direction this starts happening.?
Some things we have tried:
He will switch HT from 1w out to 5w out - no change
Tried different PL tones
Tried no PL tone at all
Moved shari location to avoid possible interference
Moved shari to 2nd floor
What we have not tried is changing shari frequency.
We're in Wisconsin and the Wisconsin band plan recommends going below 430mhz (don't have it in front of me) for links/hotspots. His Shari is around 425mhz. We have put the Shari antenna on a VNA and noted that it is not optimal for 425mhz, but again, the issue
is with the Shari rx, not tx. He can hear the Shari perfectly from further than he can tx into it with 5w.
We've talked about testing a frequency above 430mhz, but does anyone have any other ideas to offer?? I've read a lot of posts about range, and I'm not expecting miles here, just more than 500'.
