CRT 7900V 2023 , why why why

[109 Jim]

yes very good radio

[WhatsWrongMyCB27]

Anyone has any problems with tx audio? Feels like it overloading audio every mode, ssb been worst in may case. It was working fine few days then its been cracking the audio, like fm there is some hissing coming with it (like ur mic wire has some bad contact) , and it really gets worst if switch mic gain lower. Its very annoying. Fm works best, even the sound is not clean. In ssb its start get more crazier and the audio loose the grip. We been trying the stock mike and also sadelta echo master and some other power mike and also Icom sm-8, what actually work pretty good in fm but gets cracked and messed up ssb. We also try to use different power supply but there is no difference. Adjusting power dont have effect on the audio but when turning mic gain lower its get bad. Almost in possible get good tx sound .Frequency also start moving up when having longer chat!!

So what could be the problem? Processor? Hope this isn't too confusing a post!!
TNX for answers!!

[Samalex]

Could be rf getting in to the radio, Try into a dummy load see if it goes away also try adjusting power down if you can and check the voltage of the power supply and ensure you have enough amps to run the radio

[delboyonline]

I agree its a very good radio and the digital noise reduction works very well however for me the s meter is anoying , i got a loan of my brothers kenwood 570 and a couple of cb types and all show what my radios are showing s0 or very slightly above however the 7900v is a 5 , a few others have said the same and i had the same with the original 7900 , it must just be those radios. i will just put the rf down and try not to think about it lol

Kenwood's are known for being 60db over 9 or nothing especially on FM

[rpcomms]

Just been reading these posts,lot of talk but havnt actually heard anyone using proper RF test equipment to do proper testing?
Without proper calibrated test kit ,your pxssing in the wind.

One Radio VS another radio is NOT a valid test because the totally sensitivity could be different and the S9 ref point could also be a different value!
Plus the linearity also could be different ie 6dB per S point,so thats 3 variable differences.

Also noted these new QX china sets are notoriously over sensitive typical -130dBm or more!,behave more like VHF High band stuff.

So Your S readings would measure more more than likely becuase the ref point if you look in that chart,and other recent cb service manuals is -67dBm=S9,which is now more a common ref point for all new cb radios from china.

Where a lot of HF gear ham or commercial typical -73dBm=S9 BUT the overal sets sensitivity is a lot less on max rf gain.

Older sets YES were very similar S9 ref ,but rx gain was a lot less on the older fm uk sets too!

Best suggestion I saw was turn ur RF gain down in the post-Am\SSB till you see literally Zero noise on the S meter,even if you loose 15dB gain ,your china CB set going to be around -116dBm/0.35uV +/-few dB's which is ample on a base station antenna,I wouldnt even worry about it,S meters are inacturate linear wise generally.
I had same issues when the President mcKingly came out,put it on antenna thought oooh dont like that on S meter,then put of test gear saw total senistivity was whooo -130dBm ,then penny dropped.
Turn RF gain down in Am\SSB mode fixed,fm does not matter as its capture affect max gain.
So the chances are the S meters are correct and not understanding the whys or theres a duff factory run of sets on the bench,a friday special as us Engineers call them!

Cant comment of the dealer saying cant be done,I would say YES can be done IF you have all the correct info from the factory,and you have proper calibrated test equipment on your site,most dealers do,but have they got the right info? that can be a issue.

If you really want to make sure could use a sig gen on CW -1khz down then calibrate S9 @-67dBm on these new sets,older sets you have to check,as it could be -73dBm=S9

From what I heard the sets are pretty good including stability on those new PCBs ,but have NOT conducted tests on bench due to a house renovation project im involed in currently,so no radio test & plays.
CRT France currently does not have a tech engineer there,but have advertised for one,this may of changed as was old news heard.

All the best guys,happy twiddling!
Hope the info helps.

73's Rob P
RP Comms.

[109 Jim]

i better get all my Ham rigs checked out then , all show a s0 noise floor on 11/10m and the 7900v shows a s5 , as i have said before the 7900v is a very good radio its just anoying to me

[Edd200sx]

i better get all my Ham rigs checked out then , all show a s0 noise floor on 11/10m and the 7900v shows a s5 , as i have said before the 7900v is a very good radio its just anoying to me

RP comms just explained it clearly?

[109 Jim]

i better get all my Ham rigs checked out then , all show a s0 noise floor on 11/10m and the 7900v shows a s5 , as i have said before the 7900v is a very good radio its just anoying to me

RP comms just explained it clearly?

i know