Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Best wishes for a successful diagnosis and repair. Let us know how it pans out.

Thanks,

Robin Midgett K4IDC

On Wed, Jan 17, 2024 at 10:20 AM Robert Lonn WA6PHN <roblonn@cox.net> wrote:

Robin, My SS HP signal generator does have an external modulation input, and I can generate an audio file, no problem with that. That might be a valid source for my test signal.. Never occurred to me,,,,

 

Probably related to me being a Football Junky.. Happy with those teams that have lost so far,, only one more to go down, Chiefs..

 

Just want new blood in the super bowl... J

 

OK on the IC-705 set up, I have dummy loads and an Audio patch cable to feed Audio from any source into the radio, made up that cable last month, so this gives me a few options to create a SSB modulated signal..

Ideas are always appreciated, TNX,, 

 

BTW, I should have been More Specific when I stated a continues signal,, Just typing to fast.. L

 

Robert  WA6PHN

 

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Robin Midgett
Sent: Wednesday, January 17, 2024 7:57 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

 

Play a .mp3 file (audio of your choice) from your computer into your IC-705 via a soundcard interface as if you were going to transmit the audio. Put the 705 on the lowest power setting & connect it to a dummy load. If you don't have or can't make a .mp3 file, email me directly. I'm good on QRZ.

You said in your original post you wanted a continuous source of test signal...is there a reason the 705 won't transmit continuously? 

Alternately, if you have a RF signal generator with an external modulation input, then connect the line out of your computer sound card to it & play YouTube audio (podcast or whatever) into the sig gen.

 

Thanks,

Robin Midgett K4IDC

 

 

On Wed, Jan 17, 2024 at 9:40 AM Robert Lonn WA6PHN <roblonn@cox.net> wrote:

Thanks for the recommendation, but none of this would work. The issue is when receiving SSB, the audio has distortion, AM reception is fine, Collins 51S-1 receiver. I am thinking something in the AGC circuit, so it can not be a steady tone, but rather something that is being modulated.

I was looking at my new RIGOL DG992 Arbitrary Waveform Generator, 100 MHz, 2 Channel, 250 MS/s, 16bit Resolution, 16 Mpts

?? It has a lot of capabilities like 2 tone injection, and some types of sweep functions?? A Christmas gift from my wife! J

 

I have done most of the restoration on it back in July, but had to set it aside till now to dive back in.

I had asked for some ideas on the Collins web site, but that lead to more dead ends.. I now have more test equipment and will look for some bad capacitors or??

The radio has one transistor in the SSB section common to both LSB and USB, so that will be my first adventure.. The Gain of the stage seems fine, but who knows… Just another adventure to dive into..

Again, I do appreciate all those that made recommendations..

Robert WA6PHN

 

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Clint, VE3CMQ
Sent: Tuesday, January 16, 2024 9:38 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

 

I'd just inject a 1KHz tone into the mic jack or aux audio input and crank the RF output of transmitter to minimum.  No fancy test gear is needed.  Transmit on USB or LSB,or AM.  Use the MOX function for transmit control.

 

Clint, VE3CMQ

 

From: Amateur-repairs@groups.io <Amateur-repairs@groups.io> On Behalf Of Robert Lonn WA6PHN via groups.io
Sent: Tuesday, 16 January 2024 10:37
To: Amateur-repairs@groups.io
Subject: [Amateur-repairs] Creating a LSB and USB Test Signal!!

 

I have been working on a receiver that has a USB and LSB problem. I am using my Icom IC-705 radio as a test source. I want to replace this with something that will generate a USB or LSB Test Signal continuously so I can inject it into the receiver and then check stages of the radio etc. etc.
I have most test equipment available but was wondering if anyone has done this and what type of test equipment setup they have used.. 
Thanks in advance for your help...
Robert WA6PHN

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