Unknown Data Signals

[radiochris123]

I have a customer that is getting interference from what sounds like random data bursts on VHF. Is there a program that can help tell what it is, or where its coming from. I'm more interested to see if it has a some kind of location Identifying Information.

Also, can I see the raw data with say hyper terminal using a data splitter. If so, how do I know baud rate, ect

Ive tried this site to compare signals:
Digital Modes Samples

Thank you

 

[ka3jjz]

Moved from the HF forum as this is a VHF question...

 

[ka3jjz]

When I think of 'random data bursts' on a VHF frequency, the first thing I think about are pagers. Paging services are notorious for not running a clean tight ship with their signal quality. Taxi services are another frequent offender. Identifying the mode isn't going to positively identify the user, necessarily. You need some way of getting a solid ID

Let's start with the KISS approach - I would park a scanner with an audio recorder package such as RecAll (there are many others) on that frequency. It's possible that during one of those data bursts you will hear a morse code (CW) ID - that's a sure indicator of the identity of the offending station. You can then copy the ID and go to the FCC website to research the callsign.

Keeping a record of the audio - along with the CW - gives you solid evidence to use when you contact the offending service.

A very simple approach, and one that depends on hearing the CW ID (if one is used), but it's a place to start. We did this on a number of occasions with 2 meter repeaters in the Baltimore area....

best regards..Mike

 

[radiochris123]

Thanks Mike.

I like the Kiss approach for everything. That's a great place to start. Ill keep u posted on what I find. in the mean time I have a data splitter on order.

 

[kb2vxa]

"It's possible that during one of those data bursts you will hear a morse code (CW) ID - that's a sure indicator of the identity of the offending station."

A possibility but be aware of the fly in the ointment. CWID (MCW) may be in common use on analog voice channels but is not the only legal station ID. As long as the transmitter IDs in required intervals in the same mode it normally transmits all legal requirements are kept. BTW, if CWID is used it will not be transmitted during a data transmission, the two modes are incompatible.

 

[radiochris123]

Well the data slicer came in. Pretty nice for home made. were waiting on the customer to give us an answer weather to proceed or not.

is there a good program or list of programs I can use with my data slicer?

 

[ka3jjz]

Use your favorite search engine and find PDW...best regards..Mike

 

[radiochris123]

Thanks mike, just downloaded it.

btw, this is the link:
Paging Decoders PDW / PocFlex

Now that is just for pagers, is there other programs that do maybe scada?