Hey everyone.
I have a 52' aluminum tower that I'll be putting up for 160-10 meters.
It's going to be base-insulated and it is mechanically suited to mount the Mesh hardware at the top. So I'm planning this out.
Does the group have experience in mounting WISP devices or our devices on base-insulated AM broadcast towers? I'm wondering about high RF voltage and the impact on the WISP device, depending of course on the HF frequency and where the voltage and current maximums are located - so to make it easy assume high RF voltage.
What considerations? What about the CAT 5 POE cable as well? Should I used special cable?
Thanks in advance.
73,
Patrick KM5L
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Mounting Ubiquity on a base-insulated HF tower
Thu, 08/18/2016 - 10:46
#1
km5l
Mounting Ubiquity on a base-insulated HF tower
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These devices are such low cost it should be a given in every tower install:
https://www.ubnt.com/accessories/ethernet-surge-protector/
I'm using the Ubiquiti ToughCable Carrier grade, have not had issues. Also, RF shielding is best if budget allows.
Joe AE6XE
Ubiquiti threads may help as commerical deployments are relateable(just much much higher power)
https://community.ubnt.com/t5/Business-Talk/AM-Radio-Towers/td-p/222947
https://community.ubnt.com/t5/airMAX-General-Discussion/Radio-station-to...
From what I generally hear the hardware itself handles high RF environments (at least FM band AM I haven't researched), the big issue is the Ethernet line (You don't use the low shield Ethernet cables you go for the heavy shielded cable) (I use the Ubuiquit Carrier grade, pain to work with but ya know I'm not going argue with that double shield in high RF environments)
Thanks,
Patrick
Is the idea to feed the tower at HF and use it as a top-loaded vertical?
In that case, you cannot just run the Ethernet cable across the base insulators. One approach would be to wind the Ethernet cable on a form so that it looked like, say, 500 ohms reactance, at the lowest frequency at which you will feet the tower. If you run the cable *inside* the tower, will help to keep RF current off of it. You want to avoid getting a high RF voltage tower-to-cable at either end of the cat 5 cable, so the best thing to do is to bond the cat 5 shield to the top *and* bottom of the tower (edit: above the insualtors) - then use the choke where the insulator is. If you are running high power, you might want to consider making the data connection by way of fiber optic. Or send only DC up there and use another radio for the link.
GL
I was thinking about mounting 3 to 4 Nanostation 2 at the top. By the way the question of top loading, I don't have a goal of top loading for HF, there's a corona ring at the top but not large - and the Nanostations won't present much top loading.
(Edit - is my thinking sound on the 3-4 nanos on the top? 50 feet high, just building out here and so I don't really know what I'll need - so I just assumed gain in every direction would be a good thing).
Anyway just thinking on this.. perhaps your idea of running DC only, and focus on choking out the RF is the wisest. I don't think I need ethernet at all. I could simply use a small node in the shack to communicate with the 3 to 4 NSs on the tower?
73,
Patrick KM5L
Am I thinking through correctly? back in '16 I ended up doing something else, don't like it, so back to this idea.
73,
Patrick KM5L