Purchased Assembled Unit - TX Audio Distorted

[Jyunte]

Hi,

I purchased a (tru)SDX from the legitimate supplier in China, as listed on DL2MAN’s website.

The unit receives fine, but transmit audio (using the built in microphone) is ridiculously distorted.

Here’s a link to an example. I recorded it on my phone which was sandwiched between the headphone speakers attached to my IC-7300 (so you can hear my non-SSB voice in the background). The (tru)SDX was attached to a dummy load about 3 feet from the IC-7300. I’ve also listened on my FT-891 and it is just as distorted:

https://1drv.ms/u/s!AmXkNhh8v_F5geQnQ1VkWKAVZKYPew

I’ve read that the buil in mic is surprisingly good… but this is terrible!

Any suggestions?

Julian

[dl6sez]

Hello OM,

you can not control ssb microphonequality on a nearby receiver really, must be at least 60dB down!
Dummyload strays rf.... and backwards coupling do all bad things!
Take your antenna and use a Websdr to control it.
It is possible that yout TX gain is wrong, 4 should be okay, see in menue.
And please read here in the forum before asking, because this was already answered 100times....
Yes there is a search function and yes it takes more time to search than simple write the question and find a guy to help you, but it would make the use of such a forum a million times better for everybody!

73 de Chris

[Luca66]

Hello, in fact as Chris has already answered, you can not control in this mode the ssb audio output. I assure you that if you listen via a websdr station, Your modulation will be acceptable.
73 Luca

[Jyunte]

Thanks to both of you who replied. I did search for a solution to this problem before I posted my question and did so again just now, and I have not found an answer... You are right, several people have posted the same question, and either they replaced components (mine was a fully assembled unit) or they were told to do what I did... put the TruSDX on a dummy load and use a small piece of wire (4 cm long, in my case) as the antenna for the receiving radio. Someone suggested the TruSDX was very sensitive to RFI. I did my testing running off a battery. Another person suggested powering the radio from USB to further reduce the power output - something I just tried and it seemed to help a little.

I have not changed any settings, with the exception that I turned -down- the mic gain from its default value of 4 to see if that helped, but it did not. It's currently back at "4". Like many others have stated, the reference frequency was off and had to be lowered slightly. When I am able to attach the TruSDX to an external antenna again, I will try monitoring on a Web SDR.

[DL2MAN]

You problem could also be this issue:
https://youtu.be/dHttnDdADqo

73 Manuel; DL2MAN

[Jyunte]

Manuel,

Thanks for the video. So I should reinstall the firmware and reset (push the VFO knob while turning on)... or just reset the (tr)uSDX?

My unit was a pre-assembled unit, so I'm not sure what equipment I need to reinstall the firmware!

Thanks,

Julian