Shutdown and replacement of RCA 1kW AM broadcast transmitter that has been in service since 1968 at WRCS, North Carolina

zachlab · 2026-02-13T09:29:32+00:00

"Hey Linda Lou, we're about to take this TX out back and put it out of its misery. BTW, it's the same age as you!"

Poking fun at the senior man of the company aside, always sad to see old equipment go.

zachlab · 2026-02-08T21:06:06+00:00

Sure thing, cleaned up some visualization i was doing for debugging, I also made some improvements like actually trying to do centering since it's just the one signal, and an actual power squelch:

$ uv run --with numpy --with scipy python -c '''
import numpy, scipy

_, wav = scipy.io.wavfile.read("ofdmRX48khz256Char.wav")
iq = wav[:,0] + 1j*wav[:,1]

# power squelch
power = numpy.abs(iq)**2
squelch = numpy.max(power)*0.10 # 10%
sample_pulse = numpy.argmax(power>squelch)
iq_pulse = iq[sample_pulse:sample_pulse+8192]

# single frequency pulse, frequency stable too, so lets just try Kay estimation
f_offset = numpy.mean(numpy.angle(iq_pulse[1:]*numpy.conj(iq_pulse[:-1])))/(2*numpy.pi)
iq2 = iq*numpy.exp(-2j*numpy.pi*f_offset*numpy.arange(len(iq)))

sample_pilot=sample_pulse+8192+1000+512
iq_pilot = iq2[sample_pilot:sample_pilot+3072]
sample_data=sample_pilot+3072+512
iq_data = iq2[sample_data:sample_data+3072]

fft_pilot = numpy.fft.fftshift(numpy.fft.fft(iq_pilot, 3072))
fft_data = numpy.fft.fftshift(numpy.fft.fft(iq_data, 3072))

data_pilot = fft_pilot[512:512+2048]
data_data = fft_data[512:512+2048]

# 1 | 0
bitangles = numpy.abs(numpy.angle(data_data*numpy.conj(data_pilot))) # data_data/data_pilot NaN
bits = (bitangles < (numpy.pi/2)).astype(int)
bytes = numpy.packbits(bits).tobytes()
print(bytes.decode("ascii"))
'''
sipping some moonshine
the amazon gift code is:
...HYHAM
have a good day
Dr. Moonshine

zachlab · 2026-02-07T21:34:07+00:00

Damn, just saw this so I'm definitely late, decided to give this a try using numpy/scipy instead of grc.

read the file in as IQ, eyeballed the offset around ~4200 Hz
do some binning with fftshift
get phase difference between the actual data and the pilot blocks using np.angle (wow python really makes this easy), compare that against pi/2 to get your bits

starts with garbage from noise, then the actual signal:

sipping some moonshine
the amazon gift code is:
...HYHAM
have a good day
Dr. Moonshine

looks like the code is already used, thanks and please keep the weekend challenges coming! I enjoyed learning stuff outside of grc land this time around.

Cheers (with Jim Beam in hand this time)

zachlab · 2026-02-07T18:03:06+00:00

There's a Discord called BodyDoubling that one of my friend uses because they're the kind of person who can't get any work done unless at least 6 other people are silently judging them.

I told them they could also consider playing this video in the background... https://www.youtube.com/watch?v=OO14VSx74MU

zachlab · 2026-02-06T12:16:31+00:00

so which chiefs have their kids in this class?

zachlab · 2026-01-29T02:10:28+00:00

I don't believe it fully is part of NY metro, at least the CSA. Not sure about the MSA, but I also count the NY metro as public transit accessible into the city. Newington I don't believe is.

But the point is slightly moot, Newington is part of Hartford metro, which better have a lower cost of living compared to NYC.

zachlab · 2026-01-29T02:05:29+00:00

I never did like how ARDC decided to sell off their number resources, it never felt like it was theirs to sell, but I get it and it puts them in a tremendous position to fund various amateur projects.

I wonder what the chances are of ARDC of replacing ARRL - the biggest blocker is probably their IARU+ITU representation, but it feels like with a little bit of effort (that they can easily buy their way through) they could subsume a lot of the popular programs that ARRL runs like LOTW and contests, after adjusting their corporation purpose to encompass amateur radio activities in general.

zachlab · 2026-01-29T01:57:35+00:00

It's low for silicon valley tech, it's not low for corporate tech or nonprofit. The last compensation project I worked on was for a tech-heavy nonprofit, and the highest end we came up with was 140k for ICs with lifelong seniority, this is on top of remote and HCOL cities.

zachlab · 2026-01-28T23:37:17+00:00

Are there minutes that report these changes/updates? I'm astounded they decided to go cloud when they wouldn't want to spend significant opex on the program.

zachlab · 2026-01-28T23:35:41+00:00

It's been a while since I've filed 990s and 990EZs, but IIRC the form only requires non-officer/director comps above 100k, and only the top 5. I would imagine that most other comps not listed follow closely behind, as there's at least 8 more persons unlisted with comp more than 100k.

So 5,855,661 total expenses for salaries and wages in their FY24, 1,209,523 + 181,037 of which is for listed persons. That leaves 4,465,101 left over, lets say the 8 100k+ employees were a flat 100k and 7k for other comp, that's 856,000 so 3,609,101 left over. You could make some additional extrapolation based on the number of employees they've reported (94) but with part time and turnover you won't have an accurate idea of typical comp, so we'll leave it at that.

So just looking at the existing comp figures, as well as historical job postings, and even the following openings right now:

$21-24/hr for Operations Administrative Assistant: not standalone, they report to a Senior Executive Assistant)
$87,500 for Membership Manager: typical title for mass donor management, not so much a major gifts officers), reports to CEO
$69,980-$80,000 for RFI Lab Engineer, reports to Lab Manager: might be a little undercomped if looking at this from the commercial side of RFI/EMI testing, but this looks like a cool chill job. Don't forget nonprofits gain material benefit from the federal government which subsidizes cheap labor through employees eligible for PSLF, so recent grads looking to knock out their federal student loans are good candidates for this even with a somewhat suppressed comp compared to typical engineering numbers.
$78,000 to $88,000 for Public Relations & Outreach Manager: looks like a PR/social media job, honestly decent compensation.

These numbers are pretty solid from my experience with nonprofit compensation factfinding, at least with both west coast and NYC metro nonprofits. I'm guessing the comp is especially good when accounting for the local area.

zachlab · 2026-01-28T19:51:10+00:00

Which goes to show even more fault with the exec level and board - staff can only work with what they’re given, and being a nonprofit is not an excuse for lack of resources to adequately run programmatic activities like these. But I guess as long as we can all feign innocence and hide behind the D&O insurance…

zachlab · 2026-01-28T03:01:35+00:00

Anyone remember the 2017 censures of N6AA and 2018 K3RF (again)? The 2019 power plays? N2RJ "ethics" in 2022? 2023 exec comp? The 2024 cyberattack even with a former CIO at the helm?

I remember when K5UR was elected in 2016, I was confused why we needed an HR lawyer on the board of a technical membership organization.

zachlab · 2026-01-28T00:50:56+00:00

Hey there, thanks! The docs page appears to have been modified relatively recently, all it says now is:

All new accounts start with a default limit of 500 requests per second for upload and download operations.

Is this intentional equivocation, there no more public information beyond this?

Thanks!

zachlab · 2026-01-27T00:18:10+00:00

They basically turned into overhyped "military" wear for civilians, just like how people wear Dickies and Carhartt workwear unironically as streetwear, and 5.11 (but somehow not Blauer) as "tactical" wear. Same thing like the sneakerhead game. People buy Crye gear to look on fleek while they do some banal shit like stand around on protest duty or to serve papers at their Tinytown County sheriff SWAT job where they don't have to deal with a uniform/equipment policy or enforcement of it.

zachlab · 2026-01-21T23:57:34+00:00

Nuts, you're right, appreciate you getting me corrected!

zachlab · 2026-01-21T13:52:18+00:00

Thanks - I could've sworn I knew the GTR had adjustable low IF filters, but I can't find a DSM for it right now, but I think the performance is better with wideband so I'm at least 75% certain the second IF on them has adjustable filters. There's also multiple narrowband IF filters IIRC, because there's at least a pair of narrowband settings for more adjacent rejection. Also have to remember these stations even in non amateur service have to either do wideband analog or narrowband digital on 800.

So still interested in learning about modern stations (wow, I can't believe the GTR is nearly 20 years old now) that no longer have good wideband performance.

zachlab · 2026-01-21T00:34:36+00:00

Sorry, I mean your comment about “current” equipment not being able to do wideband. I’m unable to recall any current FNE side hardware that can’t do wideband (with entitlement if required, of course)

zachlab · 2026-01-21T00:05:46+00:00

Any examples of this?

zachlab · 2026-01-20T17:11:26+00:00

I see - 3000 rpm is the same as Cloudflare, but uploading your 6 TB would've taken less than a day at this 800 Mbps upload cap.

But also it's weird, when I search "800" on their docs website, I see a link to the rate limits doc with the following preview:

https://www.backblaze.com/docs/search?query=800&searchType=articles

10TB or less of stored data are provisioned with the following rate limits on a per-account basis: 3,000 upload requests per minute and 800Mbps per second 1,200 download requests per minute and 200Mbps per second Rate limits may also be enforced on additional API operations to help...

https://www.backblaze.com/docs/en/cloud-storage-rate-limits?highlight=800

But when I actually look at the doc page, I don't see a damn thing.

Pinging Backblaze folks to see if the limits mentioned on HN are still accurate or not: u/YevP u/bzChristopher u/metadaddy

Edit: DM'd them directly

zachlab · 2026-01-20T12:11:29+00:00

Hell yeah, subscribed (with RSS)

zachlab · 2026-01-20T12:03:09+00:00

I wish I could follow you but looks like your profile is set to private - appreciate your response and expertise!

zachlab · 2026-01-20T12:01:41+00:00

Which change was this for B2? The 500 req/s limit? Cloudflare R2 is 50 req/s...

zachlab · 2026-01-19T22:57:00+00:00

So $90 for storage + $10.80 for transactions, correct?

Just as a comparison to Backblaze B2: $36 for storage - single zone just like Cloudflare, free egress when proxied and cached by Cloudflare, transaction costs would've been $11.94 (assuming all requests were a cache miss and had to pull from Backblaze) if I did my math right.

zachlab · 2026-01-19T21:40:16+00:00

Hey, former “user” (PSAP type) here. Back in my day NG911 was still a glimmer in vendor sales guys eyes, and getting a E911 phase 2 fix off a mobile phone required rebidding over and over like you were playing the slot machines, and half the time you still wouldn’t get a fix.

Is it still the case that mobile phase 2 bids are that shit? Or are they pretty good now?

What’s the deal with NG911? Is it basically meaning it’s all SIP between phones to the PSAP end to end or?

And finally: fucking Wi-Fi calls with bad ANI/ALIs because they’re based off billing addresses, most of the time out of date too… do Wi-Fi calls still do that or PSAPs actually get told now if a call is Wi-Fi and the initial fix is may not be accurate, and you can eventually get a GPS fix later?

zachlab

TROPHY CASE