I was attempting to load it on 17m in the 15m band position. Isn't there a known nasty choke resonance on this amp in the 17m band? I suspect the choke needs replacing, also the fried resistor, as a
One point to remember about network ("Notwork") analysers is that they, like vector voltmeter and directional coupler measurements, rely on the accuracy of the couplers. If you are measuring an imped
My guess is that the software in modern VNAs can take this into account, but I might well be wrong. I'm sure there will be an Agilent application note (I mean sales literature) on this!! It's interes
Metal migration is well known on DC, and increases rapidly with temperature. However, reversing the polarity of the filament supply on each switch on, combined with surge current limitation, should g
You can find info on dual directional couplers in: ARRL Handbooks for about the last four or five years. Wes Hayward's book on RF Design. At least one of the ARRL antenna books. 73 Peter G3RZP ______
Glycol/water mixtures were in use as antifreeze in aircraft cooling systems well prior to WW2. Examples were (are?) Spitfires and Hurricanes, among others. 73 Peter G3RZP ____________________________
Peter -- Which is the better coolant, pure ethylene glycol or pure water? Dunno!! Just that reading about WW2 aeroplanes, they refer to glycol cooling. I suspect pure glycol may be better. As G3SEK o
from 90 to 800 volts break-down. Note that the breakdown voltage at something like a 100 or 200 volts/microsecond rise time can be as high as 1kV for a 90v beakdown gap - according to the data sheet.
They are suited for single-frequency operation. The difference between 60% efficiency and 90% efficiency with the same input power is 0.3 S-unit or 1.76db. How do you make them linear? Can you mainta
The original EER technique was written up by Kahn back in about 1953. Both Polar and Cartesian loop build on this: they have the advantage that they eliminate the AM-PM conversion difficulty. Of the
The polar loop system is a variation of the DAF amplifier. I think that there's a fundamental difference between the DAF and polar loop. The major one is that polar loop has a negative feedback mecha
There was quite a good one in the old RCA app notes. The problem is that you need a zero impedance supply pushing a constant base current into the devices, possibly even reducing slightly, as the tem
What they did for sensing the heat was use the base to emitter junction of a transistor as a diode. They mount the tab of the transistor as close to the finals as possible onto the heatsink. As the h
There are adaptors around that the probes plug into, which adapt to BNC plugs. There are also pieces of through line with N connectors one each end (one male, one female): these are about 1 inch long
Another point about the effects of local boiling can be found in the Nagayoka curves. The thin sheath of steam insulates the metal from the water, so it gets hotter, so the steam sheath gets a bit th
With the FT102, switch the speech processor ON. Don't use much processing unless you consider soncitions require it - about 2 or 3dB will be adequate, and then adjust the drive control (the top knob
Nylon does happen to pretty high water absorption, so it may well show up badly in a microwave oven, depending on where it's been stored. 73 Peter G3RZP ______________________________________________
I have a high-pot tester and here at 120m above sea level I do not see corona at 6kV. You can't always physically see corona. It does make an electrial noise however, which is how the real high volta
How do real high potential testers manage to get a microphone inside vacuum capacitors and vacuum relays? Once corona (or any other breakdown)starts, there's a current. Sample that current and use an
Even assuming there is no benefit to the Nichrome-style suppressor At least the nichrome won't drift high in value as the carbon resistors are likely to do, so the long term benefit could be worth th