i have a 10 meter radio mobile. i have a loud popping when the
mic is keyed in the external speaker. its very annoying. the
schematics shows the audio ic amp being switched off when transmiting.
when it should be biased off. poor design. its there a simple fix
to stop this pop noise when keying up? thanks

 

schematics need to be posted...........

 

http://www.cbtricks.com/radios/rci/ss_3900eghp_american_spirit/graphics/ss_3900eghp_sch.pdf

 

It sounds like there might be an issue with the switching within the radio. Make sure your antenna has a good ground. Make sure your radio has a good ground as well. Another possible solution is to put a low value .001uF to .1uF capacitor in series with the speaker positive. And/or wrap a few turns of the speaker positive wire around a ferrite bead. The bead should choke out most stray RF the speaker wire may be picking up.

 

i have a 10 meter radio mobile. i have a loud popping when the
mic is keyed in the external speaker. its very annoying. the
schematics shows the audio ic amp being switched off when transmiting.
when it should be biased off. poor design. its there a simple fix
to stop this pop noise when keying up? thanks

Can you hear the popping using the internal speaker?
If not,is the external speaker a passive one,or does it have a built in amplifier?
If it is only happening with the external speaker,perhaps it is an RF pickup problem.

You could probably use a relay to disable the speaker when the PTT operates.
I d suggest you ask on QRZ.com as well,but a word of caution--many Hams don't like the "Ranger" series of radios & may give you a hard time!
Most of them are ready to help,however,after they have had their say.

 

Can you hear the popping using the internal speaker? yes
If not,is the external speaker a passive one,or does it have a built in amplifier?
If it is only happening with the external speaker,perhaps it is an RF pickup problem.

You could probably use a relay to disable the speaker when the PTT operates.
I d suggest you ask on QRZ.com as well,but a word of caution--many Hams don't like the "Ranger" series of radios & may give you a hard time!
Most of them are ready to help,however,after they have had their say.

​

 

It sounds like there might be an issue with the switching within the radio. Make sure your antenna has a good ground. Make sure your radio has a good ground as well. Another possible solution is to put a low value .001uF to .1uF capacitor in series with the speaker positive. And/or wrap a few turns of the speaker positive wire around a ferrite bead. The bead should choke out most stray RF the speaker wire may be picking up.

True. the switching transistors switch the audio ic amp a 5 watt monolithic audio amp off when keying the mic. this is where the pop
comes from. it should have been biased off.

i tried a tried a 4.7 uf cap across the speaker terminals. i did not help.
my thought on a resistor in series with the + line. would lower the pop
at the same time when having to turn the volume up more because of
the resistance the pop is still gonna be there???

 

Can you hear the popping using the internal speaker? yes

OK,you've discovered one thing-----the external speaker is nothing to do with the problem.

The other posters are mainly thinking about RF getting back into your speaker amp in the instant that the Transmit function is keyed.

You can prove this isn't the problem by disabling the Transmit function---no RF,no feedback.

I haven't dived into the equivalent circuits from other Radios,but from memory,they switch the amplifier off in the same way,so maybe you have a real fault,not a design problem.

I haven't seen a lot of comments on the 'Net about this problem as would seem likely if they all did it.

Are you a Ham?----if not,transmitting,with this Radio is probably illegal in your country in any case!

 

If you need legal advice, this is probably a good place to look.

http://transition.fcc.gov/mb/audio/bickel/amfmrule.html

If you need electronic advice, you're already at one of the good sites.

 

If you need legal advice, this is probably a good place to look.

http://transition.fcc.gov/mb/audio/bickel/amfmrule.html

If you need electronic advice, you're already at one of the good sites.

There is always a Smart one in the crowd......

 

"10 meter mobile radios" are frequently used illegaly as cb radios, and modified with some weird mods. some are in the speaker circuit, to give strange chirps when the mic is first presssed, and some to provide "talk back" or listening to your own voice on transmit. look for any signs of modifications, spliced wires, or signs of soldering in the audio output stage.

 

There is always a Smart one in the crowd......

Are you referring to the Lawyer? or the guy that seemed to object to finding legal advice on so many RF threads?

 

Are you referring to the Lawyer? or the guy that seemed to object to finding legal advice on so many RF threads?

 

There is nothing illegal about the radio. All i need to know is there a way to stop the pop on transmit. I came to this site
to get information for a fix, is there anyone that might have a solution ? Thanks

 

What does the talk back switch do?

 

Is that like side tone?

 

Thanks, the talkback switch enables you to hear yourself in the speaker when on. I have 3 of these radios 2 of them have no talkback switch. The weird thing is when talkback is enabled the pop goes away. The problem is i dont want to hear talkback .
The pop is annoying. It is caused by the audio ic being switched of or muted . It should have been biased off. pin 3 of the ic
which is 5.8 watts ta 72222 is the muting pin would a cap to ground off pin 3 help ?

 

I'm going to assume that you just acquired unit and do not know it's history. I did a search on startpage.com for "popping sound when keying ranger radio". There are many examples of talk back circuit mods. Unfortunately, these radio's can be abused in many ways. Also, look for mic mods.

 

I think there is no fix...... thanks for the reply.

 

exceept for a few newer radios, the audip output ic is used for both recieve and transmit. you never said the model of the radio, if its an electronic switched radio or relay switched. if electronic switched, the recieve audio quits when the mic is unplugged, on the electronic switched radios, the spacing or timing of the contacts in the mic can cause the pop, usually because of trying to stay in recieve when switching to transmit and visa versa.