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Messages - Discriminator

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PDW Support / Re: Hmmm FSK to USB interface
« on: 05 Feb 2020, 20:13:35 »
Excellent. As mentioned in my email: If you zoom in to the manual, you will see that both switches are in the off position. To avoid confusion, as a double check the text ‘off-off’ has been added.

In the original POCSAG standard, the function bit is used to determine whether a message is numerical (POCSAG-1) or alphanumerical (POCSAG-4). However, many operators don't adhere to the standard. In that case, PDW makes a best guess. In 'Options - Options', you can select to display messages both numerical and alphanumerical.

Possibly by leaving out the 10k resistor, the interface or the scanner got overloaded, resulting in the wrong decoding in PDW.

The UBC355CLT looks like your UBC355XLT.



Discriminator Outputs / Re: No line in on HP Pavilion laptop
« on: 16 Sep 2019, 16:11:41 »
Ah, OK. The interfaces are for paging. For AIS, you need a soundcard. A cheap USB soundcard will do.


Thank you Steve!

Sorry to see a declining use of paging systems in Australia. I still see added value over GSM/UMTS/LTE/5G, e.g. reliability and deep indoor coverage.

Data Slicers and Interfaces / FSK to USB Interface Enclosure
« on: 13 Sep 2019, 15:26:01 »

Based on user requests, it has been a long cherished wish to realize a matching enclosure for the USB interface. With the recent purchase of a Prusa I3 MK3 3D printer, finally these requests can be accommodated.

The enclosure comes in 3 colors: black, red and silver. Quality PLA filament is used on a powder coated steel bed, which gives the enclosure a nice looking textured surface. The lid is mounted on the case by a snap-fit connection.

Prices and 'Buy Now' buttons for instant ordering can be found on the Order page.

Discriminator Outputs / Re: USB interface connection issue
« on: 27 Apr 2019, 15:50:05 »
After email contact, it appeared that the AR8600 detector output on pin 2 only is only enabled in NFM, while Geoff was using WFM for the pager signals. Mode changed and all working great.

Discriminator Outputs / Re: Swissphone DE920
« on: 28 Feb 2019, 10:08:59 »
Yes, probably. The DE920 has a TA31145 receiver IC.

Unfiltered audio is available on pin 9. You should disable baterry saving by pulling pin 13 ('BS') high.


PDW Support / Re: Help with Error in PDW
« on: 28 Feb 2019, 10:02:05 »
If anybody else has the same type of problem, then check that your pc has permissions to allow PDW to access your microphone.
This was the problem with mine, soon as I changed the permissions from no to yes, PDW started working perfectly.

Interesting problem. Thank you for sharing the solution!


Discriminator Outputs / 'Is a resistor necessary?'
« on: 14 Feb 2019, 18:48:56 »
Today in my email, a question about the need to use a resistor in a discriminator output. My reply:

Is safe sex necessary?  ;) - 'Discriminator Outputs', Question 6 -

'What's the function of the resistor?

Connecting or disconnecting an interface to the discriminator output might cause a short-circuit. The limiting resistor prevents the discriminator IC from being loaded or damaged. Further to that, it prevents your PC's microphone or line input from being overloaded.'

Is it possible that I may have damaged one of them by picking it up while it was running since it did not have a plastic case around it.

I don't think it's your fault. One interface had a defective voltage inverter IC. The other interface had a 10 uF capacitor in the inverter circuit that has developed a  high ESR. These things can happen over time.


I'm happy to announce that the 4 level interface is available again. Although the demand has decreased considerably over time, I have received several requests for the interface, mainly from the US.

Main hurdle to continue the interface was the circuit board. I have found a supplier that can produce quality boards in low volumes at an economically feasible price.


All interfaces can be repaired at a reasonable price. It's always (much) cheaper than a new interface. I will send you an email with my address.

Unfortunately, I don't have matching plastic enclosures for my interfaces. You may wish to consider to put the interface in a cheap plastic soap box and drill the necessary holes.



Thanks Steve  :)

But just curious what that triangle is for.

If the decoding quality drops below a certain value, the triangle will show.

The discriminator tap sounds like a better option

Yes. Check the domain name of this forum/site.

but not sure how to do it

Why not?

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