Netmetal5+RocketDish30 vs QRT5

RouterOS Wireless Networking
1

Good day everybody. I have a series of long links with QRT5 and I have decided to improve them with RocketDish antenna 30dB and Netmetal5.
When I installed the first RocketDish antenna on a link 36Km I was surprised by their low signal levels below the QRT5 installed on the same tower by little meter away. In the first image you could appreciate the data from both hooked to the same Access Point

Being a location difficult to reach with little useful work time (high mountain) I installed another Rocketdish 30 with Netmetal 5 in my roof pointing to a tower at 2km, doubling the link from another QRT5.

Again signal levels are disappointing.

Anyone have any idea of the problem?

36Km LINK:

2KM LINK

2

Hola,

First thing point I’d check: mANT30 is a very directive antenna (double of a Rocketdish), while the QRT beam opens more than 10 degrees both horizontally and vertically, the mANT beam is 2,5 degrees.

This means that QRTs are very “permissive” on aiming, while a mANT30 is much, much less forgiving on aiming precision (but picks up much much less undesirable signals thanks to its narrower beam); sounds to me you may have linked either a primary lobe with a secondary lobe, or maybe even between two secondary lobes between both antennas.

Judging by those figures, and assuming pigtails, etc are fine, seems to me your link needs work in aiming to properly tune it, look at each chain signal, there’s almost a 20dBm difference between them: either bad aiming, or fresnel problem.

Have you tried using the same channel you use on the QRT, on the netmetal?

3

This is what I meant:

Bad aimed link, between secondary lobes (exagerated):

(its equally unefficient a link between the main lobe on one side and a secondary on the other).

Perfect link, between main lobes:

which mANT30 antennas do you have? -PA (precision adjustment) or not PA version?

4

Not PA version, aiming was aproximate. I will try to find or make something to do a finer aiming.

Thank you very much for your tips.

5

A budget link calculator (there are several online free to use) can be very useful to get at least the azimut angles at each end as a reference, so that you can use a compass on site for approximate aiming (which is tricky also due to the metal objects like the tower structure, etc affects the compass precision).

At least will provide you a ballpark figure.

Please report back and let us know…

Suerte!

6

It Worked! It was a bad pointing issue. I got a mANT30-PA and now signal is as expected.

It is my first time with dish antenna and I didn’t imagine they needed a precision alignment.

Thank you very much everybody for your help.

TIP: never never never buy dish antennas without Precision Alignment.

7

Turn down the power. You will get much better performance.

8

Why not set the antenna gain properly? It seems everyone has mix interpretations of this.

I have been adjusting power for a long time and there are post here that say don’t touch the power setting, use antenna gain instead.

Thoughts?

Sent from my SM-G920I using Tapatalk

9

Exactly. Set regulatory domain and use proper antenna gain. Then check the results and make fine tuning if necessary.

10

Cannot agree more regarding mANT30’s. :smiley:

I second what jarda and Arcee advised, Optimum signal being around -50 (look at SNR!)

11

I use antenna without Precision Alignment and it was very easy to align. Also first time signal was very bad but because I had previous experience with all kind of antennas, in max 30 sec antenna was aligned by phone :smiley:
Precision Alignment is not required if you know what signal to expect and know what you are doing.