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Interference with 440 repeater

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Interference with 440 repeater

Is it possible for a pair of M2 Nanostations to interfere with a 440 MHZ repeater?

We installed a a pair on M2's and a PTZ camera on a tower in the middle of August and have had no issues with it until tonight. When the 440 link came up right before our weekly net it started making a lot of extra noise and tones, these would come and go a little bit. Even after the net they continued. I just returned home from the tower site and as soon as I unplugged the nodes the noise quit.

Here is a picture of the installation, One node is on the tower and the other is on the mast for the 440 antenna.

Thanks for any information
Rick KB0VZP 


If it is as close to that element as it appears in that picture I would say it's definately possible. Since it just started after working ok for a few months, I would power on each node individually and also replace/swap power injectors to narrow it down. Injectors have been known to go bad and produce weird effects. Do the same with the camera and also spin it and see if the sound changes.
N2MH's picture
Move the Nodes down a little bit

Keep in mind that both nodes have active electronics in a housing that is not shielded. Also, both nodes are in the near field of the antenna. Not only can broadband noise from the nodes get into the 440 antenna but the transmit RF from that antenna can get into the nodes and cause unknown problems. I'd move the nodes at least 5 feet down the tower and get some separation from the antenna. Ditto for the camera.


Still confused on why it has
Still confused on why it has worked fine for 2 months, This is a temporary location for this 440 antenna. There is another antenna at the top of this tower at 360 feet but has a bad connector/hardline and requires a certified tower climber to repair it. We are still looking for someone that can do this job in our price range.I rented a 55 foot boom lift to install the nodes and camera. If I go down to much lower I have problems connecting to the next node about 10 miles away. will look at getting the lift again and moving the nodes and converting these to a M3.
RF Armor
There are some kits from that can help with the back side of the nanostation but at that range I don't think it would do much. Is the Cat5/6 shielded and grounded? If you do upgrade and this is a single point-to-point link, go for a dish, PowerBeam or Rocket+Dish.
Yes these are primarily a
Yes these are primarily a single point to point feed and there are dishes at the other end of each link, We dont have a lot of options on this tower being able to put anything much bigger, How about a 3 Gig Rocket with a Omni antenna and then the M3 nano bridge at the other end. I have had a lot better through put on the 3 gig links than the M2's. I May be able to go down the tower a little but have guy wires above and lift limitations going up.

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