Magnum S45HP 70w carrier on SSB

[louie123]

Mine will work fine when cold (when it hasn't been turned on for a few days) but a few minutes after on and keying, or switching modes (from lsb to usb, etc) the carrier shows up.

And thanks, 440, I'll see if I can figure it out.

I just bought one and get carriers on usb and lsb would like to know what it is caused by.

 

[9C1Driver]

I would first double check by turned the mic gain down to zero and make sure you don't have a power mic in line. Sometimes when in SSB mode room noise can appear on a watt meter to look like a small carrier level.

 

[louie123]

I would first double check by turned the mic gain down to zero and make sure you don't have a power mic in line. Sometimes when in SSB mode room noise can appear on a watt meter to look like a small carrier level.

it is a full 60 watt carrier, no noise in room.

 

[GnG8d]

it is a full 60 watt carrier, no noise in room.

Power mic? With the mic gain off? It's possible to run gain on a power mic hot enough to do that in a dead quiet room.

 

[222DBFL]

I have a couple of magnum radios and I know that if the VSWR readings are bad it will cause this issue as well, have seen it myself. Check all coax connections and make sure that radio has a 1.3:1 or less VSWR reading. This may or may not be the cause, but will cause the issue you are seeing from my own experience with the magnum 257hp's. Rfx75 doesn't like to play with high swr readings.

 

[Retro CB Guy]

Hi has anyone got or know of someone who has or was able to get the new Grant 2 modded with clarifier opened up, modulation limiter dealt with or just got all around good clean LOUD audio done, and can share
that info with links or how to so I can share the documentations with my veteran tech in my area ? My Grant 2 already has the channel mod done so I get all bands!

Thanks for you time and help kindly, Jim

 

[Robb]

Couple of things:

Uniden hasn't been releasing the schematic to many of their radios over the last few years, since some take advantage of it and hack the radios. The only ones who have it are the authorized repair stations, which are few and do not share that info with the public.

As far as modulation limiter removal on a export type radio, why bother? I mean, if you want that kind of AM modulation that completely and automatically destroys SSB mode; then why bother buying an export radio and waste your money in the first place? Save your money and get a AM-only radio and then have at it. Export radio could never, ever match that kind of AM modulation restricted by its basic design - no matter how it is modded.

If your radio tech cannot look at a circuit and figure out where things are, then he cannot be much of a tech - sorry to say. To unlock a clarifier circuit, the basic rule to to remove the diode that blocks out voltage from the TX line and then supply it with +8v. Pretty universal. True; having a schematic would make it easier to do.

Sorry for the rant; but I am still holding out believing that in this day of mass information/communication, these issues would have been understood more clearly and not need to be explained. But thank you anyway for bringing it up just the same . . .

 

[sp5it]

1. Key radio w/o mic
2. Use dummy load.
3. Check VR of balanced modulator.
4. What is SWR on dummy load when carrier appear?
Mike

 

[Captain Kilowatt]

Power mic? With the mic gain off? It's possible to run gain on a power mic hot enough to do that in a dead quiet room.

If a power mic causes a radio to show full power out when cranked up in a dead quiet room then the microphone must be causing an oscillation somewhere in the audio chain, likely from far too much gain. Sometimes those oscillations are too high in frequency to hear.

 

[JCH]

I just bought one and get carriers on usb and lsb would like to know what it is caused by.

I've never had mine fixed. Probably won't, radio is a pos in my opinion.

 

[Robb]

FYI - this radio is based upon the same chassis as the Galaxy 3600xx. So it is no different in that respect. The failure of these radio is due primarily from over-driving them, which is unnecessary. They peak these radios from the factory, so no further mods are ever needed. Most shops can handle that fix since that part of the chassis is no different than a Galaxy. Still have both of my S-45's!

 

[magnuman]

FYI - this radio is based upon the same chassis as the Galaxy 3600xx. So it is no different in that respect. The failure of these radio is due primarily from over-driving them, which is unnecessary. They peak these radios from the factory, so no further mods are ever needed. Most shops can handle that fix since that part of the chassis is no different than a Galaxy. Still have both of my S-45's!

Which Galaxy radios ever used these "S-45" boards?

 

[Robb]

Which Galaxy radios ever used these "S-45" boards?

They didn't; you misunderstood -or I wrote it wrong. Either way, the S-45 basic design is close to the ept3600-14 chassis. Look at those schematics and you will see many similarities. The big difference is - of course - is that the S-45 uses a microprocessor to control the freq synthesis instead of using a pll and loop osc circuit. But the modulation stage and other stages are practically the same thing . . .

 

[magnuman]

They didn't; you misunderstood -or I wrote it wrong. Either way, the S-45 basic design is close to the ept3600-14 chassis. Look at those schematics and you will see many similarities. The big difference is - of course - is that the S-45 uses a microprocessor to control the freq synthesis instead of using a pll and loop osc circuit. But the modulation stage and other stages are practically the same thing . . .

Now I am understanding...