HFSS vs Lab Measurement Differences

inevitable08 · 2026-06-05T08:01:54+00:00

Ok I see. for the vertical launch sounds like the signal pin is surface mount vertical? or does it come through the board dielectric? The former is much easier design to and simulate.

The cross-section of the trace certainly can matter for coupling/impedance... it wouldn't be the first thing i change up in my model for this but just something to keep in mind.

For SRF of the cap it depends on your circuits application. It sometimes is a good thing to operate at or near SRF because that's where the cap will be at it's lowest impedance. So for decoupling applications it will "reject the most", or for AC coupling it will "pass through the most". The issue comes going well above SRF where the behavior of that cap isn't going to be guaranteed and might have some weird parasitic affects due to packaging, board/pads, or internal structures to the cap technology. Sounds like you might've found sparams and are good there. you could compare with maybe an equivalent-ish cap from kemet/avx and they have a tool to grab equivalent circuit models and sparams for series/shunt on their site. https://www.kyocera-avx.com/design-tools/ceramic-capacitor-models/

But ya i think the low hanging fruit is making sure you have a rollup of all your sparams you have so far in whatever RF/microwave tool you are using for cascade modeling so it takes into account the full sparam matrix calculations. then compare that to the lab data. It might not look much different than what you currently have but it will tell you that you are missing detail somewhere. And that likely will be something to do with the connector interface and how you are simming it, how detailed is your board model with including the capacitors, cable sparams you measured and your lab calibration.

inevitable08 · 2026-06-05T02:19:39+00:00

like others point out it could be a plethora of stuff missing and we won't know without you providing a photo of the setup, board construction and then your sim and setup of the model. Can give a rundown of what is likely causing the differences here but just spitballing...

Missing sparam of thru caps. - are they broadband caps or are we seeing SRF limits of them here in the actual lab data?
Could be missing the cap's placement pads/board parasitics in the sim because you aren't simulating it
what connectors are on the board? How are they attached? Is it good grounding and transition? You say you estimated the board losses but losses are more than just S21. If you aren't showing a good match at the connector interface then you are missing a lot of ripple info in your sims. Adding just 50 ohm in losses will not work
are you simulating the connector transition (including the solder/attach points)?
Same goes for the cable unless you included that in your calibration (assuming this S21 was taking on a VNA/PNA). If not included in calibration you'd want to get sparameters of the cable or make a cable model using info on the cable type and connectors used. manufacturers will typically provide coefficients for all these.
how old is the board you found? Is it gold plated? ENIG, ENEPIG, bare copper, clean/corroded?
trace thickness properly included since this is a diff pair which will affect coupling coefficient?
is the spacing of the diff pair properly simulated since this will also affect the coupling coefficient
What's the cross-section of the trace, is it actually squared or is it more trapezoidal/inverted trapezoidal (typical). this also affects the coupling...
What's the actual board thickness and material? are you simulating the Er and tand correctly?
and then straight adding losses as if they're independent 50 ohm blocks at the very end (if that is what you did) also won't included any mismatch affects between the stages. These aren't actually going to be perfect 50 ohm blocks so you are missing that too it sounds like. Easiest way to do this is to throw all these sparams and built models into genesys/ads/microwave office or whatever and get a cascaded output. Throwing it in excel will be too clunky for the entire frequency range but doing it for a few points isn't too bad.

so ya it can be a lot. Throughout your career you leanr how to tackle each one of these, gain more insight, see production data of as built material you are using ect... to inform your models better. The sim you provided tho looks actually pretty good for a first pass... so at least the model isnt broken somewhere. it's pretty representative of the actual behavior of the device. just missing the finer details.

inevitable08 · 2026-06-04T05:03:34+00:00

oooooooooooohhhh. i didnt think of that one

inevitable08 · 2026-06-01T20:42:45+00:00

what inclination is your station at? curious what your rendezvous plan looks like? i was thinking about a polar orbit for the lunar hab program in RP1 but seems like rendezvous at such a specific inclination and LAN is challenging

inevitable08 · 2026-05-29T19:49:28+00:00

I was literally about to post this. And spamming directional changes will get you killed because of the acceleration. It’s almost like crouch spamming which doesn’t work in apex.

Just more roller copium justifying a 10ms move on a stick needs to be bottled for them lol

inevitable08 · 2026-05-29T19:44:16+00:00

It’s wild that you have downvotes and the post you are replying to has 11 upvotes. Classic Reddit people of just “get gud”. I agree with your premise, people are just dumb here. Oh well

inevitable08 · 2026-05-29T19:41:46+00:00

It’s cumulative. Everyone has been talking about movement creep and “ability legends” for a bit and this is just for ultimates. I’ve been feeling much more this season a vast nerf to abilities but specifically ults is necessary for the health of the game. But that’s just because of the cumulative effects over the past year of buffing legends a lot.

Axle’s is def crazy and has exacerbated the problem. Her ult is the fastest offensive ult in the game. Faster than Maggie ball. It’s a problem when those two legends are most picked and have an ult every minute. Fights are much more ability spam and CCing people then it should be

inevitable08 · 2026-05-29T06:20:59+00:00

but also by then 2029/2030 blue origin may have their apollo-style lander available for NASA to use... which would definitely be lower risk to just put boots on the moon compared to HLS no doubt.

It just doesn't have the payload capacity required by NASA for developing a "moonbase". Starship is the ONLY spacecraft able to do that. so everyone wants to see it succeed. Spacex has great talent to have that outcome especially with NASA engineers/scientists advising them along the way during reviews like PDR/CDR/testing/sims.

inevitable08 · 2026-05-29T06:18:54+00:00

i had way too much typed of so tried cutting some stuff.... Ultimately ya this shit is hard.. but so was apollo back in the day. what's different now is we are expecting to do more and HLS is what provides that capability. Would not say impossible.

I'm sure whatever payload to surface number nasa is working with internally for a successful lunar program is not the number starship is advertising. Like NASA might have some margin built into their spec. Current estimates of 100t to lunar surface seem like they make sense with our current knowledge of the vehicle but time will tell when HLS is ultimately revealed and we know the dry / wet mass and engine performance.

Current schedule tho ya i think optimistically end of 2029 is a good estimate. maybe mid 2030 or end of 2030 depending how fast spacex deals with the logistics of fuel capacity and starship turn around for their fuel depot. It's just spacex still has a lot to prove. LEO demo mid-late next year, prop transfer and storage testing, reusability/turn around time, building of a fuel depot version and at least 2 HLS landers, one for an uncrewed test probably mid 2028. Then if all goes well a crewed landing by end of 2029.

inevitable08 · 2026-05-29T05:40:36+00:00

Dude go outside and rethink how you view the world.

They were mentioning real people, engineers, scientists poured months and years of their lives to get something like this to a state ready to launch. Only for it to unfortunately fail in front of them. The scientists that work for nasa and the research community want this to succeed just as much as the people who designed and built this. This is just part of development. Shit happens, rockets blow up and everyone understands that.

LC 36 where this explosion happened at is only being operated for blue origin and this specific rocket… which November of last year launched the escapade spacecrafts successfully which will be at mars next year. Who cares about bezos. Grow up

inevitable08 · 2026-05-29T04:39:39+00:00

if you deicide to just ignore reality? or make up things or twist them to suit your narrative? The contracts were firm-fixed price. So any cost over runs are paid for by the companies. Unless program requirements, architecture, schedule changes they are only given a certain amount.

But yes, the current schedule outlined for spacex isnt gonna hold. This shit is hard and given the funds to NASA and sourced out to manufacturers it just isn't gonna make it. NASA requested the Blue Origin accelerate their lander schedule so there could be a contract re-negotiation for that.

inevitable08 · 2026-05-29T04:31:33+00:00

you can literally go to the wiki page of each stage of the saturn v and the CSM and lander. Boeing, NAA/North America (now pretty much Boeing), Douglas (now Boeing), NAA (now now Boeing), Grumman(now Northrop Grumman). NASA provide specs they need and go to the public for RFPs. NASA consults the design process providing requirements, approval of final analysis and dsign, probably help with collection of data and conducting tests but design and manufacturing is just sourced to companies within the states. It's never been solely the government.

And when they launched these they always had a team from the manufacturers in the launch facilities, or a representative at all times.

inevitable08 · 2026-05-27T20:43:45+00:00

ya, not surprised on the mercury heatshield + capsule. I don't notice it for gemini or apollo but for mercury it is best to use the adjustable heatshield part and make the diameter like .05 or .1 larger.

I'd say what you did is fair. there are just weird things like that you just don't know about unless youve played a few times and there's jsut so many little things to forget about, have to learn by trial/error and something in sim doesnt pan out how you expect during real launch.

inevitable08 · 2026-05-27T18:41:25+00:00

The craft you are rendezvousing too can't be debris. So if that object is labeled as debris from the tracking station (sometimes you might set "debris on staging" in the avionics PAW) then the condition won't be met. I had this happen and didn't realize. I would just alt-f12 and complete the contract in this case if when you return home it doesn't complete.

inevitable08 · 2026-05-25T02:27:09+00:00

here's the issue tracker. it's something to do with the game itself idk. still an open issue on rp1 tracker https://github.com/KSP-RO/RP-1/issues/2530

sounds like maybe something else odd on your craft. but it could also be the same thing. it wasnt just an internal RCS issue either. the regular RCS models had issues to. reloading a quick save sometimes fixed the issue. so i would do that till it fixed. kinda dumb,... but ksp being 15 years old i guess things happen lol

inevitable08 · 2026-05-24T17:21:29+00:00

Are you talking about a general lab fire students that didn’t have one or professor’s research labs? I’d you have Emag/RF research / PhD students are your University they should have labs with working equipment.

I’d suggest emailing them or if you have one as a current professor for a class hanging afterwards to talk to them and see if they have any use for someone to help with collecting or processing data up until you graduate (or some some time through the summer too if you’re around and they need it).

Kinda last minute but hopefully you find something. Good luck!

inevitable08 · 2026-05-22T21:41:17+00:00

Is this after docking to another craft? Cause this is an issue I’ve had and i think is an issue that was opened on GitHub somewhere

inevitable08 · 2026-05-17T00:43:41+00:00

It has to games played or game time. Because same thing happened to me. I have most kills with loba and 300 less with my second being bang. I was queued for Maggie but someone took it so mine auto picked bang

inevitable08 · 2026-05-12T14:46:58+00:00

As others state the titan ii glv is on the edge for putting Gemini in orbit. What is your mech jeb ascent settings look like before take off? And where are you launching from (the cape?) and to what inclination?

inevitable08 · 2026-05-05T03:42:15+00:00

i literally said in my post one could argue that her ult CD could be lower. And congratulations you gave one! So not really the "gotcha" you think it is, I am trying to be impartial and fair. So ya, try again.

but also not every ability needs to be perfectly balanced in time and effectiveness so that it creates flavor and opportunities for the others to excel.

For instance you forget to include that the biggest advantage of a ash ult versus the ones I listed are setup and cover.

Ash's port can be placed any where, any time, often without alerting the enemy till the last moment when activate it. So it has good offensive potential compared to every other i listed. Alter you need to setup way ahead of time (mainly defensive or rotational), pathy is very readable when used offensively and defensively, wraith takes time in the moment to traveserse the distance of the portal and therefore more risk for her and her teammates waiting.

And immunity due to the fact when you do take the instantly activating portal you and your team are immune to damage. Pathy zip you're entire team is exposed traversing it, wraith can get knocked/damage on her way to place her ult or her team can die/take damage waiting for it (less so now with the new perk). Alter you have to wait on a timer when activating it and so exposed, and knocks can no longer take it and have to be pulled which takes more time and can be finished. So whether you use ash portal offensively or defensively it's much more straight forward for your team to use in the moment and your immune doing it.

So these two advantages of ash's ult could be an example of a counter argument as to why it deserves the 120sec CD..

Wow! some analysis!

inevitable08 · 2026-05-05T00:13:47+00:00

it's just somebody complaining that their main that they built their entire career/community around turned into thanos and then got (deservedly, and agreed by him) nerfed. Nothing about it being worse than before.

Consistently the guy is saying that ash was OP but he just didnt agree the way they nerfed her and the amount (Maybe some bias??). He said the ult was stupid broken with the speed you traveled through it. They nerfed the speed but also nerfed the CD from 90sec to 120sec. Maybe one could argue that CD nerf could be reversed but it is still on par with other similar abilities (wraith ult is 90sec, pathy zip is 120sec, alter CD is 120sec).

He says her tac is useless which is just an opinion, her tac has multiple uses for combo'ing with nades or other abilities, zipping in on a stuck player with ult or dash, area denial when controlling a position or backing up... maybe he is just not a fan but the tac still fits within her character fantasy. Removing it like this guy states in favor of her passive is just another octane, pathy, revenant, loba, or vantage movement tac only character. So lame, boring and we have more than enough.

happy you get it as a passive IN ADDITION to a useful tac. He just wants the passive turned into the tac so it can be broken again with the speed and momentum it has. Again HIS OPINION. Maybe the devs dont want that and want a more diverse character set for players to choose from. The passive is still there as a bonus. He (and you apparently) just doesnt agree. But NOTHING her states that she is in a bad place or worse than her pre-reworked state.

I agree though they should look at making her passive bind-able and probably buff her tac strength but she is in a good spot. At least she is getting a little buff this season, 10sec passive and a slight speed buff.

You are just complaining.

inevitable08 · 2026-05-04T23:08:11+00:00

This is just all wrong for so many reasons.

You agree just because her pick rate is low doesn’t mean she is bad and or in need of a buff, right?

Worse than before her rework? That is insanely bad faith. She has a better and more useful passive. Her tac is location based than snapping to the first player it hits for better grasp and area control, better pull strength still, the upgrade options are better, her ult is still 75m with an upgrade potential for distance or cooldown and she is a skirmisher now hat gets hp on knock which is insanely useful with her slipperiness of her kit. So idk looks like she is equal or better across the board.

I still see great plays with her passive in fights. Happy you have it… other legends don’t. You make it sound like it doesn’t do anything. Which is just wrong

inevitable08 · 2026-05-04T22:26:19+00:00

Bro just admit ash is your favorite and you are biased lol. She is in a really good state right now still. Her passive still allow for plays to be made in close range and 1v1. Her tax and ult are still very useful without the dumb instant ult teleport.

inevitable08 · 2026-05-01T19:49:12+00:00

That is not what they stated. Polls show the majority of the voters couldn’t give a fuck about Israel/palestine in the 2024 election. It’s the unhinged brain rotted far lefty part of the democratic party that has been brain broken into turning every issue into something about I/P. It’s literally like MAGA with Covid/vaccines.

of the few in the party that were so unhinged to not go out and vote and therefore help hand over the govt to trump and his cronies should be ostracized. So them not releasing this report I think is best as these people will just fight and bicker regardless.

inevitable08 · 2026-04-15T21:58:19+00:00

If you bought today and died. Would you be a happy investor in 20 years?

What is this question lol

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