Recieve Alignment Cobra 25 ltd classic

[JMessenger]

I just recently started to take an interest in cb radio repair ( i know, WHY!) well it is something that i have been interested in my whole life, and i needed a new hobby (NOT!)

But on the question: I have a Tenma 72-585 signal generator that has the built in 1 Khz tone. and when i check it from the front jacks i get 968 Mhz which is in itself ok. but when i set the frequency to 27.185 (19) and use the internal generator I measure 1937 Khz at the radio speaker which is double what it should be. Now i know it is probably something obvious here, but shouldn't i be reading 968 Khz at the speaker instead??

What am i missing guys?

 

[WA0CBW]

I think you are confused on the frequencies. I doubt you are getting 968 Mhz at the front Jack's. It is more likely 986 Hz. Just slightly lower than 1000 Hz (1Khz). Don't know what you are using to measure the tone frequency at the speaker (or why) but you may be over driving the frequency measuring device causing it to give the wrong reading of 1937 Hz or 1.937 Khz.. You should have the same frequency at the speaker as what you modulated the generator with. Don't get mixed up on your use of Hz, Khz, and Mhz.
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[JMessenger]

Your correct i am getting 968 Hz at the post, sorry about the fat fingers there, i was just measuring the audio tone via microphone coming out of the speaker assuming that i would be getting a 1 Khz tone out when putting a 1 Khz tone in.

am i wrong?

Not crucial, but I would like to understand the doubling of frequency. I suspect there is a logical explanation

Thanks for the reply

 

[WA0CBW]

Exactly what are you using to measure the audio frequency at the speaker?
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[cmdrwill]

Exactly what are you using to measure the audio frequency at the speaker?
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And, if there is distortion in the audio due to bad audio amp or mis alignment of the receiver, then the freq counter may 'count' the harmonic.