Rolling noise on 2m

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Re: Rolling noise on 2m

Postby cprobertson1 » Mon Mar 19, 2018 3:17 pm

m0lsx wrote:And I bet the earphone cable is around 1 meter long? So a nice half wave.


Ha-ha! Spot on! :thumbup: - see, now that is one of the gotchas! they should make clear in the manual... ;) Even if it was obvious in retrospect (my hindsight is 20/20).

I take it I can fix that by getting a shorter pair of earphones, or by putting an appropriate ferrite on the earphone line?


I had a walk around on Saturday but ended up getting distracted by projects back at the house, so I wasn't as thorough as I could have been!

I suspect one of the more common noise sources I hear within maybe 100kHz of 144.250 can be explained by my scanner picking up the edge of a Ham USB transmission - just enough to open the squelch. Sometimes you can even faintly make out the fuzzy-sounding voice - though other times you can just hear the clicking-noise.

The noise really does remind me of a digital signal - I just can't explain why it is in the places I'm seeing it! (Unless, of course, it's a harmonic I'm picking up!)

I also heard what I suspect may be a local driving school giving directions on 144.425MHz last night - right in the middle of the Ham 2M propagation-beacon allocation. I hope that was just a harmonic, but I was unable to pick up where it originated if that were the case!

I'm not convinced I'll be able to track down the source of the interference - it's just a pity it moves around so much, making lockout difficult (or worse, impossible if it falls on a common ham frequency, like 145.500 which is where it was hanging around this morning)


Either way, it's a nice day again today - I'll go for a walk down by the river I think! Might as well enjoy it while it's here.

I'll update you again in a week if I find anything new.
cprobertson1
 
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Re: Rolling noise on 2m

Postby cprobertson1 » Fri Mar 23, 2018 9:46 am

Managed to get some of it on my Yaesu's Waterfall Display the other night.

At first I thought it was just local noise (this was observed from the house with a roof-mounted colinear) - but it sounds very similar to the noise I was hearing on the scanner, and it was drifting at roughly the same rate.

It's like that the full way up and down the 2m Band - from 140MHz up to ~160MHz (where it gets pretty quiet again)

With the scanner, it's picking up pretty much all of that regardless of the squelch.

Also interesting to note is that it ended very abruptly, it just went quiet with no warning - no fading.

Of course, given the location of where I saw this... it's also possible I was just picking up the neighbour's TV and the resemblance to what I've heard on the scanner is just a coincidence :P

I think I'll just have to live with it! I've now circled Irvine on foot and not really got any meaningful data from it (where I was and wasn't able to pick it up seemed pretty random)

As a side note, and a bit of a funny - one of the more prominent noise sources was on 144.250±100kHz... Yeah, whoops! Turns out it was a ham SSB transmission and I was picking up the edges of it... :embarrased: Trap for young players!
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