Radio Discussion Community

Sorry to all you experts for this might be a little long winded,I am using a ROADCOM CB and a SIRIO MAGMOUNT I shortened the coax not knowing I shouldn't of done this !!!! I have had it lengthened again but I am not sure if its the right length now??? ALSO if put a circuit tester on the male and female parts of the coax plug it makes a circuit ????not sure if it should???? I don't understant how a cb aerial works regarding circuits etc CAN ANYBODY PLEASE HELP?????

Mmmm, and whilst we're at it, does anyone know the correct length for the cable attached to a Thunderpole (Astra Communications) Excalibur?

Hi Malone,

Check out: http://www.firestik.com and look at their tech help section, it should have all you wan to know there.

All the best....P

length of cable connected to antenna does not realy matter the only one that realy does get affected by it is the k40 anyother antenna can be swred by adjusting the antenn length ie wilson 1000 on a mag mount can be either 18" long or as it comes both will swr down to 1.2

b

the short you get is the design of the antenna if it connects by so239 plug then a short should be apparent if it connects by 3/8 thread as in dv27 type antenna then there should be no short

b

Co-ax lengths I've found are best kept to multiples of 9ft.. e: 9, 18, 27 etc, as this is approx the wavelength that 27megs likes best. Try and keep the co-ax in 1 length if possible to avoid loss of power output through leakage of RF, and use thicker low-loss co-ax if you have long lengths of say over 18 ft (Not really possible on a mobile set-up though, but you can get thinner low-loss stuff at some places which has shielding around it). Seal the co-ax/plug joint with good quality insulation tape if outside as water will get in through capillary action, also known as water ingression. This can cause a short circuit and the SWR will shoot up and possibly damage your rig. Hope this is useful to someone out there.