Hello, I’m new to this and very excited to be transmitting. My current setup involves close to 40 feet of LMR 400 connecting my roof antenna to my raspberry pi in the basement. Curious to know if there would be any advantage in converting my setup to instead wire into a weatherproof box that has inside all the hardware/software included and resting on the roof just a few feet from the antenna. I would have to run power and ethernet to the roof but hopping this would boost my reception and transmission. I’m not seeing anyone with a similar setup so I’m thinking perhaps I’m out to lunch. Thoughts on pros and cons from the veterans out there?
Hi, just out of curiosity, how high up is your antenna? I’ve noticed in my stats you are in my local area and i can’t see, to get quite close to your numbers and have wondered about you setup.
In theory yes, but the online calc.says 40 ft of LMR400 will cost you 2dB of attenuation.
Given the connectors account for a part of that (and you have them regardless of length), there isn’t much to be saved there.
With a roof mounted antenna and quality coax, you are off to a good start.
What type of dongle do you use? Maybe there is an improvement to be had there.
Personally, I don’t think you’ll gain much. Any db loss from the LMR cable will be minimal. The possible issues with rain and heat on the electronics would be enough to make me keep them indoors. Not to mention access to the pi if something were to go wrong. I don’t want to keep climbing on my roof! HA!
Anyway, I did see a youtube video of someone who did something similar. If you haven’t seen it I can try to find the link.
i also use LMR400. i have a filtered LNA in a small weather proof box right at the roof mounted antenna but keep the PI and power supply for the bias tee indoors. i have done this for about 3 to 4 years now with no LNA issues. (RTL-SDR.com filtered LNA)
Thanks. I’m using the Flightaware provided Pro Stick Plus (blue dongle) with the 1090MHz Antenna also sold by flightaware.
I figured I would need some fans to keep it cool in the summer. I do wonder in winter how the hardware and software would do in the cold.
I estimate my antenna to be approximately 360 feet ASL. This is based on the antenna being on my roof at approximately 30 feet from the ground and assessed area AGL from: Map Elevation Calculator. I have fairly clear skies from this vantage point.
Any experience with splitters? If I want to run more devices from my LMR 400 connected to the antenna atuned to 1090MHZ, do I lose a lot by using a splitter? Or perhaps I should instead get another antenna and coax and copy the same system? LMR 400 is not cheap…
Ah, i’ve estimated mine around 335 ASL total in the Bayside area. I’ve assumed the hills in the county towards Mountain View are blocking some of my farther range as i’m getting decent results all the way to Scranton. Kind of lacking to the north west. Looking at ways to bring it up another couple feet.
I see you are using a Flightfeeder. What coax do they provide you? And is it the blue or orange box?
15 meter, 50 ohm, the one listed on their website from what I could tell. It is the orange one. They did ship a filter with it but i’ve found there isn’t enough noise around me from what i can tell to justify it.
Yeah, they run pretty hot in summer without some sort of cooling. Keeping the box out of the direct sun is the single best thing you can do.
Cold isn’t a problem so long as you can keep it dry.
Adding a splitter will immediately half your signal strength (-3dB min).
Depending on the splitter, it may allow a lot of noise generated in each receiver to get into the other further reducing performance.
Okay. What about adding an LNA? Would that boost my signal or my LMR as it is does the trick?
Your prostick plus already has an amp, so be careful adding too much extra gain.
That said, an LNA will more than offset the loss from a splitter etc.
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