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Call Sign : 26-CT-989 Posts : 22 Times Thanked : 0 Join date : 2020-01-13 QTH or Location : Clacton on sea essex Equipment Used : CRT ss9900 with solarcon aerial Age : 56
Subject: Scratchy audio??? Fri Mar 06, 2020 11:24 pm
Hi all,I have a yaesu ft900at and what a great radio it is.unfortunately this evening everyone is saying my audio sounds scratchy but can’t think of anything I’ve done apart from leave my extra coax coiled up (usually spread it out) and had my power supply nearer to the radio .....could any or both of these cause this?? Also 3 operators also said I sounded off frequency on fm,yet my read out was saying I was spot onSorry if this is a silly question but pulling my hair out here .thanks for any advice .antenna is still up and decent coax and still an set of 1.2 ish
26TC62 Senior contributor
Call Sign : 26TC62, 26CT2817 Posts : 141 Times Thanked : 29 Join date : 2019-06-27 QTH or Location : Portsmouth Equipment Used : Yaesu 891, 10m pole, wire 5/8, T2LT
Subject: Re: Scratchy audio??? Sat Mar 07, 2020 8:41 am
The coax and antenna setup aren't likely to be a factor here unless it is RF feedback getting into the radio, which is possible. I don't know the 900 but on SSB, have you checked the ALC setting is within the suggested range? The most common cause of distortion on SSB is overdriving. That won't be why people have said your FM sounds off frequency, but you can check that yourself if you can get a signal into a WebSDR even if you don't have a frequency counter or another receiver to hand.
Victor CT Directors
Call Sign : 26-CT-3228 / M7VIC Posts : 6269 Times Thanked : 389 Join date : 2019-11-10 QTH or Location : Bedford Equipment Used : Various
Subject: Re: Scratchy audio??? Sat Mar 07, 2020 9:39 am
The WebSDR suggestion is brilliant (Never even occurred to me and great idea if one is in range.)
Unless you can hear it for yourself or from an actual trusted source you'll be lost. 'Scratchy' is hardly a very descriptive word for audio quality unless you're playing an old beat up vinyl record The operators that said your FM was off, was this on UK CB frequencies? If so there is always the old '125' argument and usually the oldest of human shortcomings, namely 'elitism'. I mean, why would your more modern 'Ham' rig with decent VFO and frequency display be any better than their old beat up 1980's CB? I hear the old "You're off frequency" line a heck of a lot. Used to be constrained to CB but you hear a lot of it on the Ham bands nowadays, (people sticking to the 0 & 5 channelised mentality).
Don't fret about it until you can truly confirm it for yourself, that "seed of doubt" that's been placed is a terrible thing to do to someone unless they are genuinely trying to help.
An old 'trick' I've used in the past when I received a report of poor audio was to ask them to wait whilst I change microphones. Then I'd pause transmission, key back up and ask them how the 'different' mic was, (whilst never actually changing the mic)....you'd be amazed how many said it was now better!! With that said, try not to be too quick to judge or call people out over it. It happens
Hopefully your rig is fine and you've just experienced poor reporting. How many 'Hams' give 5/9 reports all of the time yet ask you to repeat your last over?
Again, don't fret unless you can truly confirm it for yourself.
Andybron New Member
Call Sign : 26-CT-989 Posts : 22 Times Thanked : 0 Join date : 2020-01-13 QTH or Location : Clacton on sea essex Equipment Used : CRT ss9900 with solarcon aerial Age : 56
Subject: Re: Scratchy audio??? Sat Mar 07, 2020 9:52 am
Thanks for the replies folks and yes was on the cb frequencies,is absolutely perfect on ssb just the cb frequency however I contacted the previous owner and he did state he never used it on those frequencies.i will see if I can borrow a frequency counter and see what’s happening n if no luck will send it off for a good service
Victor CT Directors
Call Sign : 26-CT-3228 / M7VIC Posts : 6269 Times Thanked : 389 Join date : 2019-11-10 QTH or Location : Bedford Equipment Used : Various
Subject: Re: Scratchy audio??? Sat Mar 07, 2020 2:30 pm
No worries Andy. You can pretty much guarantee that there is nothing wrong with your rig now that you've confirmed to me this was on UK CB frequencies. Heard the same line time and time again Do whatever you need to do to reassure yourself but don't kick yourself after forking out for a service that yields the same bad reporting results. On a decent rig FM modulation should be clean as a telephone line, (300hz - 3khz audio filtering), which it usually is on a decent amateur radio rig, the same is not always true on an old CB radio. (I've seen badly designed filters let alone the golden screwdriver experts that clip the components around the filter to make it sound "more bassy"!) Maybe that's what they meant by "scratchy"? Possibly more treble than they're used to
Borrowing a frequency counter may seem like a good idea but only if it is truly calibrated or accurate will it help. (How many out there have a GPS disciplined clock source for their frequency counter?)
It's as the old saying goes..... Give a man a clock and he will always know the time. Give him two clocks and he will never know the time.
All the best to you, Victor
Andybron New Member
Call Sign : 26-CT-989 Posts : 22 Times Thanked : 0 Join date : 2020-01-13 QTH or Location : Clacton on sea essex Equipment Used : CRT ss9900 with solarcon aerial Age : 56
Subject: Re: Scratchy audio??? Sat Mar 07, 2020 11:53 pm
Thanks again all I tried the alc switch and it was transmitting way way over the scale!!! So processor on and mic gain turned right back to half seems about right.however am still to try it on air as it’s late and it’s dead around here but fingers crossed is I fine now
Northern Crusader Major contributor
Call Sign : M0GVZ / 26CT1760 Posts : 536 Times Thanked : 35 Join date : 2019-11-13 QTH or Location : IO94SA Equipment Used : Icom 7300, TS480, President McKinley, Albrecht AE6110, CRT Mike Age : 54
Subject: Re: Scratchy audio??? Sun Mar 08, 2020 2:11 pm
The ALC meter shouldn't be showing more than half on voice peaks and ideally showing very little at all. Remember the ALC meter is indicating how much the ALC circuit is having to limit inputted audio so as to try to not overdrive the radio so the more it reads the more it's having to do.
In an ideal world everyone would have a proper peak hold power meter and a FM deviation/AM Modulation meter. For SSB they'd wind the mic gain down to zero and increase the mic gain whilst speaking until the meter showed the max power reading of the radio and leave the mic gain sat there. It would mean very little, if anything, was shown on the ALC meter and you'd have good clean non splattering signals. For FM you'd use the deviation meter, repeat the above, stopping increasing the mic gain when the deviation reached 2.5kHz. For AM you'd use the modulation meter to increase the mic gain until it was just nudging 100%.