but are useless if you +/-5% works out, according to my calculator as +/- 0.22dB. Prodigious!!! If we go look at professional standards for 'Type Approving' equipment, we see that an approved accredi
I don't know what 'Type Approving' equipment is, Equipment that has to be 'Type Approved' before being placed on the market. Conducted measurements to 5% by calorimetric methods do rely on the mismat
For real fun, how do you measure the power (with what accuracy?) into a load such as marine antenna at 2MHz? The dummy load is typically 10 ohms in series with 250pF: a DC calorimetric method might d
The readings of power out on bird wattmeter have been as accurate as can be obtained. That is a matter of some contention! Firstly, as someone said, it doesn't really matter that much as far as we're
The international limits can be found in ITU-R Recommendation SM329-10. The limits there for amateur equipment are: below 30MHz: 43 + 10 log P dB without needing to exceed 50dB P is the PEP above 30M
Use a Delta Electronics TCT current transformer to get the current component. Or use a Pearson current transformer. Use a voltage divider (like the Jennings glass vacuum capacitor unit) and a meter w
Reading the FCC definition of PEP it goes something like: Peak envelope power is the AVERAGE power in one RF cycle at the crest of the modulation envelope. It is actually the ITU definition - if I re
The FCC does not measure power at amateur radio stations with a Bird 43. As a matter of interest, what do they use? Or do they not actually bother measuring the power of amateur stations unless there
Another problem with calorimetry is the time it takes, which with a sweep tube amplifier would be prohibitive - even pulsed! I haven't seen a 'scope guaranteed better than 5%, even the new super doop
Life would be so much easier if my customers would understood that sometimes a dB really doesn't matter. If they understood that most of the time, a dB doesn't really matter, it would help me!! 73 Pe
I don't think there's a lot of disagreement between G8WRB and myself. We seem both to be very dubious about the accuracy of using an oscilloscope, and recognise the problems with calorimeters. Incide
Many years ago ( more than I really wish to remember, but this discussion has reminded me) we sat ina class in college and drew a graph of Irms times V rs to get rs power, and as I remember, it looke
have a question in regards to rf getting into my filament meter. What sort of meter? I've never yet really got the RF out of things enough to make sense of a digital meter...... 73 Peter G3RZP ______
Or maybe some would just like it quiet with no discussions at all? Or maybe anything other than a very basic simplified answer is too advanced for some people? Far more advanced fora than this have s
To me, I cant see any difference in the action of a triode or a transistor if the transistor is biased correctly. The main difference is the way the collector/drain/plate current varies with collecto
Bear in mind that even double sided copper clad is a bit too thin to be an effective shield at 80 or 160. From memory, you need about 15 mil (.015 inch) to be totally affective at 2MHz i.e. 10 skin t
One point to be considered is that on the whole, cooling is probably easier for a tube amplifier. Especially if you want the capability of running SSTV or RTTY for long periods. 73 Peter G3RZP ______
I did some rough science checks on a 250H Bird 43 insert. I did not find that using it resulted in readings that were dramatically low just below 2 MHz. The handbook for the Bird 43 gives some indica
I like to fing a circuit diagrm of HT regulated power supply of 250 volts using 6080 tube..... ARRL handbooks 1951 to 1964. Some have 6AS7 instead of 6080, but for all intents and purposes, they are
But you must be able to disable the agc or it won't work. You must also make sure that the receiver audio dynamic range is sufficient. F'r instance, if the the AF output is set to 50mW without the am