A little correction: MRI systems require a VERY linear RF system: they don't tolerate well a high content of harmonics and/or IMD. This is the reason for the 100mA quiescent current setting: it allow
BTW, something that might just work: there's a company named Ceramic Magnetics in cube format with quite a hefty cross sectional area. Never used them but they may be worth a try, instead of Tomita A
Hi everybody: FET's , per se, don't have any intrinsic time related effects. On the other hand a CW wave is actually a 50% square wave, producing in effect a 50% duty cycle. This might indicate that
Absolutely not! I am referring to the RF cycle itself, not the envelope. During one dit, you send a few millions of them! Since the FET has no storage effects, a high frequency signal is seen as a tr
Why remove it? Black is beautiful! Just make sure to clean it around the assembly holes. Anodize is an insulator, being an oxide. You can even engrave on it all the markings. Alex 4Z5KS Hi all...I ha
Did you try to breathe them? Alex 4Z5KS --Original Message-- From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On Behalf Of n8de@thepoint.net Sent: Thursday, March 01, 2012 6:20
You need diodes of a PIV of 1600*1.41 volts (2250V) minimum. Of course you have to take some safety margin into account: on the order of 3000 PIV ... Alex 4Z5KS --Original Message-- From: amps-bounce
...because you'll need at least 3 per leg and for a full bridge this will make 12 diodes. Easier to look for TV replacement diodes Alex 4Z5KS --Original Message-- From: amps-bounces@contesting.com [m
..modern RF transistors are enclosed in a so called cavity package: the upper side of the die and the top cover are separated by an air gap. The vast majority of the heat is transferred through the m
First of all I would like to correct a small misconception about the little side hole in the center pin of all connectors: it is there to provide a visual verification of the placement of the central
This is definitely true, although in the Signal corps we used crimped connectors all over in field installations and vehicular use with no problems. Modern connectors are nickel coated and surface tr
...it's not becoming brittle due to heat! It becoming oxidized by air under the influence of heat: the hotter the faster. As for not soldering : in high power systems, especially in CCS, operating te
A valid point! It seems to me that, originally, RF cabling was almost universally in the hands of knowledgeable people, technicians and amateurs. They would have been much more aware of the possible
You do! Tokyo High Power have one of these based on ARF 1500 transistors. They have a Vds of 600V so that they can operate on mains voltage-rectified and filtered. Now, Microsemi market the ARF 1501A
Why not just put the soldering iron in contact with the pin's back shell. Even if you smear a little solder on it, it doesn't come into play so far as the contact goes. Alex 4Z5KS I have found an eas
Guys, what you describe here is transformer saturation! Most likely using too small core. Alex 4Z5KS Bob, That typically happens when your output network isn't correctly done. There is an incredible
A better replacement would be a new pair of schottky diodes' something like 1N5711. I had the same problem with the coupler in the TS 140 I use. After repeated breakdowns I replaced both and all my t
...just be aware that germanium is very sensitive to thermal shock during soldering and unsoldering. They can change characteristics in pernicious ways due to heating; and after heing them 4 times...
You can try Noalox (as per antenna joint compound). It should remove the grime and prevent reformation as well.just try hard not to put on too much, since it can develop conductive paths between coil
Check the bleeder resistors too. They are prone to opening up with a very small clearance and arcing can develop across the gap. Alex 4Z5KS If the arcing started after the caps were changed Id start