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Biged
| | Posted on Sunday, July 07, 2002 - 7:25 pm: | 
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Here is a question that I have been pondering on posting. It probably is just an obvious one but everybody complains about the freq drift on galaxy radios. Being an owner of several of them myself, I know the counter is a little off when it is very cold or when it has been sitting in the heat all day while I am at work. But is the freq really off? Could it be just the counter that is drifting or is the radio itself off a little? Now keep in mind I never talk sideband so maybe this is the area I would noticeit but as far as AM, I cant tell the difference in performance...Eddie |
Tech181
| | Posted on Monday, July 08, 2002 - 12:07 am: |
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Biged,
Yes, there is some amount of unstableness (is that even a word?) on SSB with the Galaxy radios. Once they "warm up" they seem to settle out decently though.
The detent in the clarifier knob will click in at around the 10 or 11 o'clock position. This is due to a design flaw in the radio itself. The clarifier pot is slightly turned to the left when it's mounted in the chassis because it will not clear a screw that's used to mount something else nearby behind the front bezel. If you take the radio apart you can easily see which screw it is I am talking about. I forget off-hand which one though.
You can remove the offending screw and loosen the clarifier pot and re-align it to the 12 o'clock position if you like without affecting the operation of the radio. Then the detent will line up with the center line above the clarifier knob.
Steve
Tech181
Tech181@copperelectronics.com |
jyd
| | Posted on Monday, July 08, 2002 - 12:44 pm: |
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307,done my vr-9000.and he done a wondrful job.he realighned my hole radio. |
Biged
| | Posted on Monday, July 08, 2002 - 9:20 pm: |
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181,
That is very good to know but what I meant was, can the freq counter be off but the radio accually be on, no matter where the clarifier knob is at. Say, channel 27.185, when I get in my truck at the end of the day and the radio has been sitting in there getting toasted, it will read something like 27.184 but after the air conditioner has been on for a few minutes, it will then sneek up to 27.185 or even 27.186 but when it is cold it will read 27.186 from the get go and then drift down to where it is supposed to be once it warms up. All the while, is the radio REALLY out of freq or is it just the counter that drifts? The reason I ask this is because I have never noticed any difference in the TX or RX. Or maybe its just too little of a difference to notice. |
ss8541
| | Posted on Monday, July 08, 2002 - 11:36 pm: |
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bigbob, both are off. the counter is not stable and neither is the vco circuit that the counter gets its reading from.
the counters oscillator seems to be more stable than the downmix oscillator for the vco. even in a controlled enviroment(indoors) the vco freq changes noticeably when monitoring with my very stable hp5328a freq counter.
the reason that it is more noticeable in ssb than am is that am uses a voltage detector for rx audio and ssb uses a product detector for rx audio. product detectors are effected by freq changes much more than voltage detectors.
all you really have to know is that the rx audio is demodulated different ways for am and ssb, with ssb being more sensitive to freq changes. and if your radio is drifting in freq, it will show on their rxing end as well as your rxing end. as stated earlier, this is for ssb. and that is no matter how stable their(the station rxing you) radio is. |
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