Galaxy 99V Bad sounding SSB

[Low_Boy]

It is hard for me to even find a thread anymore because all titles run up and down, Not lengthwise. Everything checks out good on this radio. I borrowed the upper shield off of another radio. The shield that covers the PLL on the solder side of the board and I am told the radio sounds better but still has a slight underwater sound. So the problem must be RF. I do not normally like to give up on these radios but I am running out of places to look.
Thanks,

 

[Onelasttime]

Did you check your crystal filter and voltage regulators? If anything is wrong with either of these nothing will make that more aware than SSB operation. Anytime I have SSB issues those are the two things I check before anything else.

 

[Low_Boy]

Did you check your crystal filter and voltage regulators? If anything is wrong with either of these nothing will make that more aware than SSB operation. Anytime I have SSB issues those are the two things I check before anything else.

 

[Low_Boy]

All Regulators check good. I have not checked the crystal filters and I am not sure how I would do that?

 

[Chevboy0167]

It would take some equipment or $1.50 off of the bay...

 

[nomadradio]

One way is to simply listen to the pitch of the receiver noise on SSB with the antenna unplugged. That way you only hear the receiver's internal noise.

Switching from USB to LSB should not make the "pitch" of the hiss change drastically. A Galaxy radio will never sound exactly the same on both sidebands. The quality of the SSB filter is not that high even on a good day.

But if there is a radical difference, make sure the carrier-crystal trimmers are set correctly. 10.6975 for LSB and 10.6925 for USB. If they have been tweaked off frequency, that will disturb the quality of the sideband transmit audio.

And if the pitch difference is really noticeable switching between sidebands, this suggests the SSB filter's passband is screwy enough to have an impact on the quality of the transmit audio.

73

 

[Low_Boy]

Thanks nomad I will try that tonight.

 

[Low_Boy]

Well Nomad I tried what you told me. Crystal filters are good
Thanks

 

[nomadradio]

What I would do next is to tune in the radio's VCO, the output from the PLL that sets your channel frequency.

If you set the Galaxy to channel 20, the VCO frequency should be 16.510 MHz. Tune in this signal. Should be able to "sniff" it near the PLL chip, or near the front-facing end of the transmitter mixer chip. Either USB or LSB will work fine on the external "sniffer" receiver. Tune it a steady tone. Turn the Galaxy's clarifier and you'll hear the pitch rise and fall in step with it. If you don't hear that, you're not listening to the correct internal signal from the radio.

Key the mike in a SSB mode and modulate the Galaxy. See if you can hear any "warble" in the pitch of the carrier's tone in the receiver.

This is one of the most-common roots of garbled SSB transmit audio,

But not the only one, by far. No point trying to fix a 'warble' problem if it's not there to start with.

If the tone in your sniffer receiver stays steady when the Galaxy is modulated in SSB transmit, your problem lies elsewhere in the radio.

I can think of four specific different kinds of distortion that we see in sideband transmitters. Warble is only one of them.

73

 

[357]

I just did a 99v for a buddy and usb sounded like shit when I set it to the book. lsb was fine.
I had to set usb to 10.6945 instead of 10.6925 and 16.2705 instead of 16.2725
other wise to audio was shifted to the high side of the sideband and sounded like garbage. I had to shift it over to the center more.
Its almost like the service manual is wrong. had the same thing with a 959

 

[Low_Boy]

It seems like something must change on one of the components because many of the old radios I align don't sound right at factory specs. but after zero beeting they are perfect. Some value must change on some component with age. Sounds crazy but?

 

[dave457]

Most galaxy radios sound like shit on ssb, there easy to spot

 

[357]

the other thing is after I tuned to offsets to the way I mentioned. usb says 27.383 (on the radios counter) but its actually on frequency and has good audio bandwidth.
all the other modes say 27.385 but as I said, if I tune it properly on usb its way off to the right on the scope and in unintelligible.
so the if filter sucks ass

 

[nomadradio]

I had to set usb to 10.6945 instead of 10.6925 and 16.2705 instead of 16.2725

This just means that the SSB crystal filter has drifted away from the frequencies in the alignment procedure. That filter is full of crystals, and they will drift with age like any other crystals. Back in the bad old days, Swan sideband ham transceivers would have you set the carrier crystal to match the "window" or passband of the crystal filter. Apparently they didn't control the specs of their crystal filter all that accurately, either. Their advice was to set the carrier frequency adjustments to match the filter's behavior, not just to an arbitrary number like the Galaxy/RCI/Connex alignment tells you.

Just one drawback. The radio's frequency display will be wrong. The internal arithmetic that allows it to show you the radio's receive frequency has the carrier frequencies hard-coded to match the numbers in the alignment procedure. If I had to choose between making the display accurate, or making the radio sound acceptable, I would go for the audio quality.

Congrats for making it sound right.

73

 

[357]

I sealed them with hot wax. you fart and they move, super lame