Radio Discussion Community

Lets keep it simple

UK FM 27.6012-27.9125mhz FM Only 27/81 MPT1320 MPT1328
and new Multi-Norm cb that can change bands legally.


EU Band FM,AM,SSB modes must be CE marked and ‘R&TTE Directive marked on any new equipment ,this can also be used on UK band cb frequencies when band switched on radio ...

Hi Mike
how is the power wired up?
direct to batteries and cables routed away from alternator?
is the screen\braid of coax properly grounded and is it quality shielded coax?

I assume the problem is when engine on,right?

reagrds

Rob

Hello
the Jopix SS3900 needs a lot of work to get them right and sound good.
I spent over 12 months fixing every single niggle with that radio and end up with something really good alla SS-3900-EU-V10
Stable now -Yes
FM spot on-fixed the poor noisy fm detector,fixed the detector range so now have ...

Hi Matt
best get it too a repair CB technician with correct test gear if guessing,trying to diagnose faults like this on forums can be very difficult
until on a radio bench to look at properly.

Handheld can often have issues with there antenna BNC socket or bad\dry solder joints on antenna ...

Have you checked the RF power into a 50 ohm dummy load plug in via a wattage meter in your CB radio with amplifier disconnected completely,check if 4w then?
What is your VSWR like,without amplifier in line?

Check you have a good 13.8Volts DC at connector end of CB,low volts can cause radio to ...

Hi
I would not bother butchering your classic cb and being technically illegal,engineering cost would not justify it.
multi-norm sets are so cheap nowadays and meet all the current legal specifications and bonus you'll have legal Am and SSB modes as bonus depending on what you buy!
Best advise from ...

Google is best friend and prob the easiest way to find something even if go schematic that helps,if your engineer minded ull figure it out.
often the user manuals have schematics in them.

try cb tricks.com
(other company) cb shop they may have manuals
also try emailing http://www.servicemanuals.co ...

The switch mod is not required on Premium version
I doubt anyone will reply to this as its a bit naughty condoning illegal mods on forum
google or take back to dealer and ask best advise.

Hello
officially there is no service manual available,dealers only im afraid.
however try cb tricks.com
simonthewizard.com
youtube can glean some information too.

Im assuming your a radio engineer or have radio engineer skills and proper test equipment to go inside radio?

Im in same boat being a ...

Hi Kevin

what antenna are you using?
What mount type ?

Have you checked antenna mount metal to body work on vehicle,make sure DISCONNECT the PL-259 Plug from radio when carry out this test!!!,check ohm continuity?
Ensure you not just getting a ground via the DC negative lead only,check that outer ...

The short you are seeing is for matching the antenna correctly and static reduction,yes its DC shorted,but not at RF sees it.

Chance are is the mount,cable or plug are are at fault.
Easy way to prove that put a PL type 50 ohm dummy load into SO-239 mount on antenna base,key up radio with VSWR meter ...

Hello
well that's not a good start is it? :(

Things to check if you got some basic test gear?
DVM on ohm continuity check patch cable has got connections and does not have a short.

Are you get a reading in reflect?
briefly remove antenna cable and press ptt switch on mic,do u get any reading?
IF ...

The sirio 5000 has a much larger bandwidth than the 145ML
If your running extra power I would advise you don't use mag mounts,as the grounding is not as good compared to a drilled in antenna and a proper DC grounded antenna connection to cars body is best.
Years in the commercial pmr business taught ...

President Grant 2 Premium
President Lincoln 2+Export version
CRT also do a few ssb models but personally id stick with President as better quality builds.

If going portable handheld I can recommend the President Randy 2,really built like professional VHF equipments and works really well and built ...

You may find with using a halfwave the lower angle of radiation may not work as good mounted low to ground compared to a quarter wave dipole which has a much high angle to get over building,hilly terrain when mounted in low position.
The higher the better with Half wave antennas.

My choice would be ...