MikroTik

Team,

I need some advice.

I have an AM tower that has an STL antenna already on it in the 700mhz range. I want to remove that, and install a Mikrotik 5ghz system. There is already a thick cable going up the tower. The tower itself is shunt fed, and the thick cable is shielded and grounded every 10 feet.

My question here is, what dish/hardware will work best for this? Electrically the grounded shunt feed effectively grounds the tower and the STL works perfectly on this without interference.
I am needing a radio that can install in place of the STL. It has to connect to the cable from the TX shack (which is essentially a faraday cage) that then goes up the tower to the antenna at the top.

I need a radio that takes an antenna and can do so with 200-250 feet of shielded coax.
The link distance is about 6.5km line of sight with no 5ghz interference.

What options are available in Mikrotik?

need a radio that takes an antenna and can do so with 200-250 feet of shielded coax.

The idea is utopian. What is the attenuation of your cable at 5GHz?
Theoretically you could try GrooveA 52 ac/Metal 52 ac with the mANT30 antenna. But I think the cable attenuation will negate the results.
But you will get much better results with the LHG XL 5 ac and twisted pair cable.

The problem with twisted pair is the shunt fed AM still radiates 5kw.
I'll have to pull out a meter and test. But basically the radio has to be separate from the antenna.

This used to have a STL at 749mhz accepting an audio feed. So i'm certain the cabling is sound. But you're right I'm not sure on the attenuation.

the shunt fed AM still radiates 5kw

Then use Mikrotik devices with a metal case QRT 5 ac or NetMetal ac² + mANT30 + Sleeve30.
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the thick cable is shielded and grounded every 10 feet.

What prevents you from doing the same with twisted pair?

Radios and/or antennas on AM broadcast tower can be entertaining!

I'm going to guess that your feedline for the STL is likely 7/8 inch hardline. Feedline loss at 5 GHz would kill your signal. For that frequency, you really need waveguide, but even with that, it would be pretty bad with that long of a run. Getting the radio onto the tower would be the solution, but has it's own set of challenges. Is your 5GHz intended as a point to point link or a sector to cover an area?

One thought would be to put two radios on the tower. One for your intended use and the second pointing down to your transmitter building. That way you only need power on the tower and that may be far easier to deal with. Although not intended for the purpose, you could likely use the the existing hardline as a power line (NOT for 120 / 240 volts AC). Send the highest DC voltage up the feedline that the radios will take and even with some voltage drop, there will be enough voltage left up on the tower to power the radios.

If getting power up there isn't a problem, why not just use fibre and SFP?