Selection of proper cable kits and mount types has become more important as we have moved up the frequency band. Very high losses and noise in a cable kit will greatly affect the performance of all systems. This is more of a problem above the UHF band.
A standard RG58 cable exhibits a loss of 20dB per 100 feet at 900 MHz. This means that the loss in a standard 17’ cable is 3.4dB. At higher frequencies the losses are even greater.
Another source of loss is in the mount itself. The NMO type mount was developed for mobile radio installation when most services operated in the 30-50 MHz range. Loss was not much of a factor at those frequencies. Today many of our systems operate will into the GHz range where loss is a big deal.
Advances have been made such as using all brass mounts to avoid corrosion but this has its drawbacks because brass is soft. If not handled carefully, a brass mount can bend or even break during installation. Its softness also affects its ability to pierce other metals during installation causing a less than perfect ground connection.
A final consideration with regard to NMO type mounts in general is the tendency for cross threading when installing an antenna because of the flats in the standard mount.
In an attempt to counteract many of these problems we patented an all brass mount with no flats, and a stainless steel piercing saddle to provide a good electrical and mechanical connection.
We developed a new technique for shielding the feed point of this mount to provide a better constant impedance low loss assembly. We combined this with our double shield high performance MicroLoss 900 cable to provide an economical solution. MicroLoss 900 cable exhibits about one-half the loss of RG58A/U but maintains the same O.D. as standard RG58.
We will continue to support all our standard mounts, including the high distributive capacity (big button) versions, but want to make sure careful consideration is taken when new and tougher applications require better solutions.