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Ok so the Microair radio is fitted and sorted, the AVmap is on its armrest mount and working with satellites & airfields galore and no gliches...The only hinderence I now have to contend with is the constant hiss of interference from the Avmap to the radio..The antenna leads are separated by 3 feet of cockpit. Of course the Avmap is fairly near the radio, but then, so is everything else. Any ideas how to damp out the radio transmissions from the AVmap? It runs, at present, on internal batteries. I can't realistically get the radio and avmap much further apart...............I would love to know where I am going without the snake impersonations in my ear.....Geoffrey.



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Hi Geoff,


I tried as an interim measure one of those bags that computer motherboards come in, the gray/black ones and wrapped it around the radio, it helped about 50% better, I then got another bag, cut it into strips so i could wind around the antenna cables to find the crook one(reduction in hisssss) but I then checked the shielding on my antenna cables and one was a bit crook so I eventually got a set of better shielded ones and made like a very basic Faraday cage from metal flywire and earthed to the common earth point around the radio which fixed the issue until I could get the radio checked out - the hisss was generated by the radio external connection to the antenna being faulty.





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OK that sounds like something I can work with. I do have a break in the antenna cable (with a correct connection) But I'll try there first. I wonder where the interference is being picked up? in the radio unit or through the antenna....I might give Microair a ring (as well as the Avmap importer) see what they recommend, We can't be alone with this problem? Thanks for the input..Geoff



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  • 3 weeks later...

ok everybody


I found that the Avmap antenna cable must not go near the mike cable.... minimum 2 foot clearance ...that where the interference was coming from. So, all's well that ends well............Geoffrey



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Guest Perry



We have found the Microair Transceiver to have a rather poor input filter and would recommend the following:


1. RF Beads on the entire harness on the back of the microair. These have a good effect on the system.


2. Attempt to install a Powerbox filter on the supply end to suppress engine induced noise. We have developed a line choke specific to the microair. We found a considerable improvement on the Microair and Xcom following such an install. Ian has stock.


3. If you can afford a Microair (They are over 4 times the price of a good quality Vertex Transceiver that is submersible), then invest in a good quality antenna. Ian also has a selection with him presently. The antenna must be properly balanced and extended with a good quality RG58 co-ax with as few connectors as possible.


4. We found that the intercom installations in the panel mounted transceivers manufactured in Australia are very simple and are good noise generators in themself. To this end we have just developed an intercom that fits onto the Microair that provides active noise cancellation. Now our trikes with Microairs can effectively fly open without visors and all sorts of wind protection for the mic as the system works better with more ambient noise. So far in testing we are getting crisp 5/5 comms over 200NM at 1,000ft and no interference from GPS, mobiles and other cockpit gadgets. With the new intercom we turn down the transmit power to 1.2W (from over 5W) and kill the transceiver side-tone altogether. It works like a charm.







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