EAS - FSK levels versus tone levels

[Bruiserr]

Hello,
Can someone tell me what the FSK levels are in an EAS message, the 3 beginning
bursts and the end of message bursts. Referenced to the 1k tone in the EAS message.
Our EAS-1 Redlich Gorman decoder manual says to set the input level to a certain marker on its built in bar graph by monitoring the normal programming level of the station on that input channel. Our EAS decoder is having problems with our assigned WX station.
I did record one DMO message and noticed that the FSK data burst were -12db of what the tone level in the middle of them was. In other words the FSK data bursts were -12db of the normal programming level of that received station being monitored. I am having difficulty decoding and logging from this station. The LP1 AM station we monitor is set up the same as far as input levels but is decoded and logged with no problems. Haven't recorded any EAS messages from that source to make comparisons from though. Since our EAS-1 is a decode only unit I can't go about sending something out thru it for test purposes. Our AM broadcast receiver is a car AM only receiver with an outside antenna - that is the channel that has no problem with decoding EAS messages.
Our WX receiver is a marine handheld on a power supply with outside antenna and coax stub trimmed to reject our FM carrier at 96.1, full quieting on receive with no desense. Also have a back up receiver on another input channel tuned to the same wx station just in case it is a receiver problem.

So, is it normal for the data bursts to be 12db below the level of the tone that is sent and the audio message?
When I contacted the manufacturer to double check that I was setting the levels correctly (I was) I mentioned the difference in audio levels between the data bursts and the normal programming and was told that it sounded like something was out of whack with that.
-Dave Corrigan for KGRU-LP

 

[tpt]

Last week we easily received our test message from NWS.

Only problem: it was from an NWS station out of Lexington, we monitor NWS Charleston. Skip brought in the Kentucky signal, when I flipped on our weather receiver all I heard was hiss.

My point is that the Gorman Redlich will decode tones just about lost in the noise. If you are getting other tests OK I would suspect that the equipment at the NWS station has serious problems. If you can get other NWS stations on your receiver you might try tuning them in next Wednesday before noon (which seems to be when they run their weekly test.

If you can't decode anybody (including non-NWS sources) then you may have a problem with the decoder. Check the ripple on the power supply first. Don't know if Gorman Redlich MFg. is around this week (it's fair week, good week to take vacation) I'll look to see if there are any cars there this morning ;-)!

BTW: Sounds like you have a strong local signal on NWS, but if you are looking for a good weather receiver, try Hamtronics. They have a kit for around $150.

 

[CW]

> Hello,
> Can someone tell me what the FSK levels are in an EAS
> message, the 3 beginning
> bursts and the end of message bursts. Referenced to the 1k
> tone in the EAS message.
> Our EAS-1 Redlich Gorman decoder manual says to set the
> input level to a certain marker on its built in bar graph by
> monitoring the normal programming level of the station on
> that input channel. Our EAS decoder is having problems with
> our assigned WX station.
> I did record one DMO message and noticed that the FSK data
> burst were -12db of what the tone level in the middle of
> them was. In other words the FSK data bursts were -12db of
> the normal programming level of that received station being
> monitored. I am having difficulty decoding and logging from
> this station. The LP1 AM station we monitor is set up the
> same as far as input levels but is decoded and logged with
> no problems. Haven't recorded any EAS messages from that
> source to make comparisons from though. Since our EAS-1 is a
> decode only unit I can't go about sending something out thru
> it for test purposes. Our AM broadcast receiver is a car AM
> only receiver with an outside antenna - that is the channel
> that has no problem with decoding EAS messages.
> Our WX receiver is a marine handheld on a power supply with
> outside antenna and coax stub trimmed to reject our FM
> carrier at 96.1, full quieting on receive with no desense.
> Also have a back up receiver on another input channel tuned
> to the same wx station just in case it is a receiver
> problem.
>
> So, is it normal for the data bursts to be 12db below the
> level of the tone that is sent and the audio message?
> When I contacted the manufacturer to double check that I was
> setting the levels correctly (I was) I mentioned the
> difference in audio levels between the data bursts and the
> normal programming and was told that it sounded like
> something was out of whack with that.
> -Dave Corrigan for KGRU-LP

-12db down from operational level or MAX level is fine..most tone decoders have as much as a 30db dynamic range...or more! Acutally TOO LOUD is worse than soft...DTMF decoders (modern ones, not older torroid style found in old KTU cards) work the same way. For tone levels, usually signalling levels should be about -10 to -13 below MAX audio levels....Sounds like the WX station encoder is not set right or outputing the wrong headers?? If you hear your LP1 ok, then I really suspect the WX SVC encoder. ALso check or twist (level difference in the separate tones) and make sure there is no EQ happening to the audio from the rcvr to the decoder...(have you tried swapping inputs to the decoder box to check the decoder channel? Thats a thought I would do first!)