@ftg@mastodon.radio
@ftg@mastodon.radio avatar

ftg

@ftg@mastodon.radio

Radio/Electronics/Telecom Geek.
He/him.
youtube.com/oh2ftg
prkele.prk.tky.fi/~ftg/
twitter.com/2ftg1

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ftg, to hamradio
@ftg@mastodon.radio avatar

That does not look right at all.
23dB attenuation in between the transverter and spectrum analyzer.
The attenuators are specced to 6GHz and 11GHz, so no problem there either.

TX gain maxed out and hitting the transverter with +20dBm on 144MHz and this is what I get.

#hamradio #9cm #3400MHz #microwaves

ftg,
@ftg@mastodon.radio avatar

@recursive
Yeah the UI is great.
And I agree on the trashed CRT.
The CRT being trashed was the reason why the whole analyzer was also trashed.
And then rescued from there by a friend and delivered to the radio club.
A working HP 8564E 40GHz capable (looked at things on 38GHz and 39GHz with it, it works!) got disposed like common eWaste.
Always worth a look into those bins.
Not even the first free garbage spectrum analyzer I have encountered, but definitely the best and most working one.

azonenberg, to random
@azonenberg@ioc.exchange avatar

New toy just showed up in the mail... It's my beta ThunderScope!

Will start playing with it after work but here's some quick unboxing pics.

Black Pelican case labeled "ThunderScope" with "made in Canada" "OSHW", and "EEVengers" logos on it
Black instrument case in foam cutout with four BNCs on one side and two on the other, labeled "ThunderScope Beta 2"

ftg,
@ftg@mastodon.radio avatar

@azonenberg @wa7iut
That sounds exiting.
Might work as the heart of a nice SDR as well.

DJDarren, to random
@DJDarren@mendeddrum.org avatar

It’s just been pointed out to me that the reason Apple runs a trade-in programme for older devices is so they can reduce the size of the used market, and has fuck all to do with recycling.

That’s blown my tiny mind.

ftg,
@ftg@mastodon.radio avatar

@PatternChaser @DJDarren
That is what is done after they have been shredded into conveniently sized pieces, yes.

azonenberg, to random
@azonenberg@ioc.exchange avatar

New thread on my big ongoing embedded project since the other one was getting too big.

To recap, this is a pilot project for a bunch of my future open hardware T&M and networking projects, validating a common platform that a lot of the future stuff is going to run on.

The primary problem it's trying to address is that I have a lot of instrumentation with trigger in/out ports, sometimes at different voltage levels, and I don't always have the same instrument sourcing the trigger every time.

So rather than moving around cables all the time and adding splitters, attenuators, amplifiers, etc. to the trigger signals I decided to make a dedicated device using an old XC7K70T-2FBG484 I had lying around.

Of course, as with any project, there was feature creep.

I'm standardizing on +48V DC for powering all of my future projects as it's high enough to move a lot of power but low enough to be mostly safe to work around live. So I needed to design and validate an intermediate bus converter to bring the 48 down to something like 12 for the rest of the system to use.

The FPGA has four 10G transceiver pairs on it. I used one for 10GbE (not that I need the bandwidth, but I was low on RJ45 ports on this bench and had some free SFP drops) and the rest are hooked up to front panel SMA ports (awaiting cables to go from PCB to panel) to generate PRBSes for instrument deskew.

Since I'm pinning out the transceivers and am planning to build a BERT eventually, I added BERT functionality to the firmware as well (still need to finish a few things but it's mostly usable now).

And since I have transceivers and access to all of the scope triggers, it would be dumb not to build a CDR trigger mode as well. That's in progress.

ftg,
@ftg@mastodon.radio avatar

@azonenberg
This thing is shaping up to look absolutely stunning when done.

ftg, to hamradio
@ftg@mastodon.radio avatar

Completely reverse engineered datapacket for Quansheng UV-K5 radio.

Not just schematics, but a complete kicad project, so that one can properly document modifications and make derivates.

https://github.com/mentalDetector/Quansheng_UV-K5_PCB_R51-V1.4_PCB_Reversing_Rev._0.9

ftg, to random
@ftg@mastodon.radio avatar

At least, the rack is accessible and more in order.

To be done:

  • Power
  • Antennas
  • Internet for linking the 70cm analog repeater.

The Sepura in the box is an SRG3900 radio programmed to our 70cm TMO base station, which is connected to the network.
The idea is to offer better indoor coverage with the TMO-DMO gateway.

The Nokia RD58 based analog 70cm repeater is planed to return to service as an experimental internet linked club repeater on R.Net2.

DM_Ronin, to embedded
@DM_Ronin@mstdn.social avatar

some hardware chips memes

#Embedded #Hardware

ftg,
@ftg@mastodon.radio avatar

@gsuberland @manawyrm @DM_Ronin
That seems to often be the suggested paste mask by manufacturers as well.
3x23 or the lesser 2x2 grid instead of on large plate.

karotte, to random
@karotte@chaos.social avatar

It's more or less widely known that especially high-capacitance ceramic capacitors have significantly less capacitance at their rated voltage than at 0V. While this effect is detrimental for bypass applications, has anyone ever turned that effect into something useful?

I was thinking of using this effect to make a variable capacitor for a VCO or maybe getting some use out of the non-exponential RC charge characteristic.

ftg,
@ftg@mastodon.radio avatar

@gsuberland @karotte
I have been thinking about using that capacitance to abuse old GaAsfets as varactors on 10GHz.

ftg,
@ftg@mastodon.radio avatar

@gsuberland @karotte
Unfortunately I think it is likely too temperature dependent to do that.
But it could be interesting to see.

A 1:47AM thought, could the body diode be used to measure the die temperature?

Then you'd have the built in temperature sensor for temperature compensation as well.

But back to DTC's. So far all of them that I have seen used a pile of switched capacitors.
Or were just ST8P switches with "bring your own capacitors".

gsuberland, to random
@gsuberland@chaos.social avatar

revision schedule 2h behind, gonna need some better living through chemistry to get through this last block

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Not one, but two hours. Urgh.
I was waiting for the democompo block to start.

ftg, to random
@ftg@mastodon.radio avatar

What uses would there be for 7638MHz and 7554MHz DRO oscillators?
Not phase locked, so not super stable, don't multiply immediately to any interesting bands either, so not that usable as a marker either.
And these have a negative supply voltage.

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Neato.
7.7GHz band microwave link crap ain't too common here.
And I only ever got these oscillators as independent modules.

ftg, to random
@ftg@mastodon.radio avatar

The current POCSAG revival with all the projects and #DAPNET is very nice.

astrid, to random
@astrid@fedi.astrid.tech avatar

L + standing wave ratio + f + C + V + P + Z

ftg,
@ftg@mastodon.radio avatar

@astrid
Putting the L in RL.

azonenberg, to random
@azonenberg@ioc.exchange avatar

Is there such a thing as a cost optimized "discharge-only" RF terminator?

Basically, something that you use for discharging ESD from cables and is built to tight mechanical tolerances on the mating interface so as to not risk damage to expensive connectors, but need not be optimized for good return loss out to mm-wave frequencies etc.

@g4dbn @ftg @dlharmon

ftg,
@ftg@mastodon.radio avatar

@azonenberg @g4dbn @dlharmon
I think so?
But my personal choice for that would likely be the cheapest terminations from a decent vendor like Huber+Suhner, Rosenberger or Radial.
The connectors are less likely to break the cable when they are from a connector vendor.
And the termination can be a cheap 3GHz one, as the RL is not really of interest.

If I'd need decent amounts of these, I'd just email those companies.
Radial will make anything for you, for a price.

ftg,
@ftg@mastodon.radio avatar

@azonenberg @dlharmon
SMPM is new and exotic enough to be decently pricy to begin with.

ftg, to random
@ftg@mastodon.radio avatar

Old cellphones were more fun.

I have converted a bunch of these to 70cm .

Btw, Nokia used to sell these things with their Actionet branded MTP1327 network.
IIRC Altai2 is one user of it's derivates, with Nokia RD72 terminals. I guess the units meant for the Chinese market could be used on the old Altai frequencies as well.

astrid, to random
@astrid@fedi.astrid.tech avatar

THESIS: computers are a liberatory force, a means for individuals to create art, improve their lives, and communicate

ANTITHESIS: computers are the tool of the authoritarian, and create alienation and systematic oppression

SYNTHESIS: you use da good computer to blow up da bad computer >:3

ftg,
@ftg@mastodon.radio avatar

@astrid
So like dis?

ftg,
@ftg@mastodon.radio avatar

@naia @astrid
Real "news" article?
Yes.

Real capability somebody had?
Lol no.

ftg,
@ftg@mastodon.radio avatar

@astrid @naia
Easier with you in it ofc.
IIRC there were some papers where they managed to wirelessly hammer the ABS break cylinders to cause problems.

hacks4pancakes, to random

IDK y’all but my ten year old Honda batteries seem to be rocking it right now in Chicago. Seems like a them problem.

ftg,
@ftg@mastodon.radio avatar

@gsuberland @hacks4pancakes
Tbh AdBlue on the diesel engine side is Eurpean (pushed by Germany as opposed Denoxium)
freezes around -20 degrees.
So the containers, pumps, sensors and valves get trashed by them freezing over and over again in the winter.
So 2 year old cars will get fun 3000-5000eur repair bills :D

ftg, to hamradio
@ftg@mastodon.radio avatar

Got myself some "new" testgear.
A classic Palomar #noisebridge

#testequipment #surplus #hamradio

ftg,
@ftg@mastodon.radio avatar

Here is it's schematic.
Pretty ingenious having that 70pF cap in series with the DUT to make the impedance measurement to work for inductive DUT's as well.

The noise source seems quite traditional amplified Zener noise source.

Here is a link to a decent quality manual for the RX100 unit:
https://www.planker.dk/PDF/Palomar%20Noise%20Bridge.pdf

gsuberland, to random
@gsuberland@chaos.social avatar

lusting after the Hakko FX-972 but by the time I add the handles and tips it's like £1300 >_<

ftg,
@ftg@mastodon.radio avatar

@azonenberg @gsuberland
How does it compare to JBC stations?

So far JBC has been the "everything seems lesser after"-station for folks I know.
I don't have one mostly due to being cheap.

ftg,
@ftg@mastodon.radio avatar

@hennichodernich @azonenberg @gsuberland
That is certainly an environment something where Metcal or Thermaltronics will win.
And also the reason why one can actually lock out the JBC temperature setting so that that cannot be done.

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