My IC-7300 will prevent transmissions if the VSWR is > 3.0. But that's protection going out. The power meter is the opposite of course, and it really can't stop anyone from connecting a 100W source and turning it on.
Interesting. Can you for example, dead short the output with no damage? If so I wonder if you could design a clamp that would save the meter. The input is a kohm? Seems like a very low capacitance TVS and a few resistors could save the IC. For the load, if the radio can handle being shorted, maybe there's a way. Then again, maybe other radios can't. We need to contact the CB amp builder and see what his 10kW amp can handle. A small SMD resistor, or even replacing that whole PCB would be cheap. Still, a fun problem to try and solve.
Will it protect itself from a shorted output when transmitting? Gee I don't know. I don't think I want to test that. Sounds a bit like the redneck thing "Here hold my beer and watch this!"
My Subaru is supposed to prevent you from crashing into the rear of a car in front - it has two cameras one on either side of the rear view mirror. I know for a fact the computer steps in and starts to "help" you because I've gotten too close to the car in front before and it starts stuttering the brakes to keep me from crashing into them. But would it actually stop if I tried an experiment and tried to ram a car in front of me? Hey Joe hold my beer ... on second thought nevermind.
A TVS, hmmm be interesting to play with. I don't know if that would work with respect to what we mean by a "transient" in the respect of the use of this device. Lets say a ham forgets what I told them, forgets the red label that will be on the back, and transmits 100 W CW into the thing - key down let's measure power!. We have seconds passing ... maybe a few seconds up to however long it takes them to realize "It ain't working and I smell that burning smell ...".
You know really I think only one ham is going to end up with this, if he wants it for my cost. As I said he well understands that this type of instrument can't take high power. He's been here and we've measured radios with my hp 437B and he sees the setup with a 40 dB atten. and how carefully I check things before pushing the PTT button.
Problem is he recognizes (thankfully I guess) he still has too much doubt in his innate "carefullness" which he has freely expressed to me. For example I got hold of an older analog Boonton power meter model 42A, which I haven't been able to fix yet. However the sensor that came with it is fine (model 41-4B). I got a really good deal on Ebay on a more modern Boonton digital meter model 4220, and it works really well with the Boonton power sensor. In fact, it reads down to -60 dBm accurately (I've tested it) which is even lower than my 437B can do.
The point is, I offered to sell him that system for my cost, but he has yet to take me up on it, and the reason is not money. He doesn't trust himself with it - because it has to have an external atten. for almost anything a ham would use it for.
All of which, only adds weight to the argument for some hams using a Bird, which has a slug clearly marked with its maximum power rating.
They lose some acccuracy, for much improved ruggedness/idiot proofness!
The funny thing is, many hams, even if they would like to use something like your device with a massive high power attenuator can't afford the latter, (unless they find one surplus), or even a Bird, so end up with much less rugged "ham" type "SWR meters" the power reading of which is questionable.
I am one of these poor hams, & my main power meter has its own built in test load, with a tap on the load resistor to allow monitoring.
I got it free, but a while later the meter movement died, & was replaced with a "generic" one of the same fsd, so now the readings are sketchy to say the least.
Being purely resistive, I could calibrate it with a DC supply, but the top range is 150W, & I don't have a 86.6 v ,1.73A DC supply!
OK, maybe 50Hz AC, but that really demands a biggish isolation transformer, a Variac, & a TRMS meter.
Of these, the only one I have is the Variac!
At the moment, the closest thing to accurate for HF & reasonably high power levels, that I have is the "twin needle" meter on the MFJ ATU.
Putting the ATU on the "external dummy load" position, & using the above test load/power meter as that "dummy load", I can read power & SWR in "MFJ talk".(either average or peak)
For low power UHF/VHF I have a little "Welz" power meter, which, for some unknown reason, has a male "N" on the end of its testload/ sensor, so you
have to use a joiner.
It goes to 15W, & has a "calibrate" knob for the various bands.
A very nice looking little unit, but its accuracy is unknown.
Really, hams don't need to know transmitter accuracy to any great degree of accuracy--a few dB either way doesn't matter.
The same goes for Reflected Power/Return loss/VSWR ---ham bands are wide, & tuning is a compromise, if you see a VSWR better than around 2.0:1 over most of the band, you can call it good.
Some really terrible antennas have nice flat VSWR across the whole of a band, & continue to catch suckers out!