Best Cable

[echo depot]

So, I'm going to run outdoors, is it worth going with Proxicast SMA Premium 400 Series Low-Loss Coax Cable (50 Ohm)? Also as far as coax is it worth getting RG-8X? or will the 400 series low loss suffice?

[vague canyon]

How long do you need it to be, loss is a factor of distance. So a cable that will suffice at 15’ may not work at all at 50’.

[wild mauve]

RG-8X is not a good choice for anything above HF really - very high loss at 1090MHz.

Proxicast claim that this CFD400 stuff exceeds LMR400 specs, which would be far better than RG-8X. The down-side is that it's difficult to work with (chunky and stiff). As CommGuy hints, it may be overkill for a short run too.

Personally I'm a fan of good quality satellite-rated RG6 (or better spec with RG6 dimensions). It's low loss, readily available, and easier to work with. Properly installing (and weatherproofing) the connectors is key.

[haughty pollen]

Note that as you are receiving only the impedance mismatch with RG6 is so small it can be safely ignored.

[echo depot]

At least 50 foot run

TY for all the input also.

I have Coax tape already for the connections, or should I shrink tube what I can?

[haughty pollen]

How many connections are you talking about? Also for a 50' run you're really going to want to have an LN adjacent to the antenna.

[vague canyon]

You going to pretty much need LMR400 at a minimum for the loss not to be great, any way to make the run shorter?

[echo depot]

If I move to wifi on the feeder

any better option then 400?

[echo depot]

What would I need for an LNA?

connection at antenna and homerun to feeder

[haughty pollen]

Something like the Uputronics. https://v3.airspy.us/product/upu-fp1090s/
I'm sure others will have suggestions as well

[haughty pollen]

So only the one connection then - where the cable connects to the antenna? With the cable then running all the way to the SDR? Remember every cable termination induces loss so the fewer the better.

[echo depot]

Ty for the link and yes just headed to the roof and theres already a 15ft tv mast up there I can go on top of, just have to follow the original cable hence the extra distance.

with the LNA im going to lose the ability to use the same antenna for 978 right?

[vague canyon]

Yes but they are not cheep, LMR at that length isn’t cheap.

[vague canyon]

No as long as it’s not a filtered one.

[haughty pollen]

Ahhh - you are US based so need the 978. Something like https://www.amazon.com/dp/B07G14Q6XX should do the job.

[echo depot]

So, because I am clueless and new to this how does one poer Bias T, or does it use voltage from the cable? And the LNA goes right after the antenna, correct?

[haughty pollen]

It uses voltage from the coax cable. Some SDRs (RTL-SDR Blog V3 and V4, some from Nooelec, and probably others I am not aware of) have the ability to provide this power to the coax. Otherwise you can use something like the below to provide the power. And yes the LNA is best located at the antenna to boost the signal prior to any cable losses.

https://www.aliexpress.com/item/1005006202645890.html

[echo depot]

Ty I'm gonna have some work ahead to figure this all out lol.

[gaunt ruin]

Definitely think hard before doing 50ft or more of cable for ghz. Can you put a raspberry pi near your attic etc. the other thing with unfiltered cheap lnas is they can be prone to overdriving without filtering. Just things to keep in mind. I’m working through this also but some things I’ve learned/been told.

[echo depot]

TY, possible to put the pi a little closer, but the antenna is going up on the roof, might be able to go 25 or 30 feet, but on wifi not LAN

[gaunt ruin]

30ft if its lmr 400 isn’t bad like 1.5 db of loss from coax just don’t go 50-100ft for adsb if possible

[haughty pollen]

Seriously, if you can get an LNA close to the antenna then the cable run and absolute losses matter far less.

[gaunt ruin]

This 100%, just consider if you want to do 978 you need another coax run and two lnas and two filters or one light blue filter or two combo filter and lnas. Also potentially another antenna. While you can put just one lna up there without a filter it will amplify the noise if my understanding is correct and can have issues with overdriving. If you only want to do 1090 though easy just one combo filter and lna from like uptronics at the antenna or a cavity filter then lna. But to summarize my rant filter plus lna at antenna = awesome like Mike said 😎