Search results

Here is the best video I found to construct and test a 4:1 balun. The video says 800W, but I'm sure larger cores could be utilized for more power. The TRX Bench channel also has 2 videos on building and testing a standard 1:1 balun. Videos #100 & #101. And part 4 was the construction and...

I don't know much of anything about the Sark100/MNI60 analyzer, but I did do some quick research on it and this is what I came up with. The windows software for it requires Windows 7 or newer. That seems to be due to the .NET Framework version that it uses. It also requires Microsoft Excel to...

It's not in my stash of documents on my phone. As soon as I get a chance I'll check my old phone and dig through all the ones on my computer. I know I saved that info somewhere. (n) Get better soon brother.

The MOSFETs aren't changing from PTC to NTC. Many MOSFETs that I've used exhibit this behavior and once you know why, it's super simple. MOSFETs have 2 separate characteristics to consider, the gate-source threshold voltage (VGSth), and the drain-source on resistance (RDSon). The VGSth has a NTC...

For simplicity, I built one like this quite a few years ago. https://www.qsl.net/kf8od/load.html If you need help locating this type of resistor, here are a couple places. http://www.usresistor.com/ - These guys make the rod resistors and many others. Not sure if they sell direct or if there...

Awesome. A couple of my coworkers and I hang out on 25 while we're trucking around the local area. About 6 months ago, at my last job, there were some of us that hung out on 3 as well. I can't wait until the last of the cold weather is gone so I can put my 11m base antenna back up. I miss being...

B = Black tins. C = Chrome tins. That's all those two letters mean. (y)

Looking at the typical power curve graphs in the RD100 datasheet, it shows that 11.5db gain point is at 10W input power, basically saturating the transistor close to 117W output. The gain goes up as you back the power down to the 100W point and goes up significantly if you are running them at...

Quite a few 100W HF rigs use the RD100HHF1 parts in their final sections. For ideas of how to properly set them up for Class-AB linear operation, you only need to look at the schematics of these radios. The Yaesu FT-450 and Kenwood TS-590S are two examples, but there are quite a few. Studying...

This guy, http://www.w6pql.com , seems to have some good designs including protection circuitry, some even into UHF territory. 73s

Since you're only interested in a digital scope and you have a tight budget, I'd consider the Rigol 1054Z 50MHz scope, then do a quick Google search for how to do the firmware "hack" to upgrade it to 100MHz. Probably one of the better bang vs. buck deals as far as new scopes go. I prefer to do...

They use a 2-tone signal for the power/gain chart (IP vs OP) because the transistor is meant for use in SSB linear applications, according to the datasheet, so output power is specified in PEP under those conditions. It also allows the use of the same test setup for both the power and IMD tests.

Watts are watts. It's irrelevant how you measure it. Those graphs apply to the test circuit used in the datasheet, so when used in a different circuit (Such as a push-pull amplifier), the graph will be different. It still doesn't matter though. According to the graph, for their test circuit, if...

If you really must do it yourself. The video I posted above is a design that works perfectly fine, and as far as I know, is very similar to the Heathkit can internals. I never had mine open. That 100W, 50 Ohm, carbon rod resistor will handle 1000W ICAS when submerged in mineral oil, no problem...

Oh, you ain't shitting that it's high. If I remember correctly, I measured the static gate capacitance at close to 4000pF or 4nF. That's pretty insane. I'm sure with a solid bias and a 9:1 or 16:1 impedance transformer on the gates, you could just brute force the gate to do as you command...

You'd be correct. There seems to be very few that use real RF devices these days. It's such a shame too.

Let be realistic here for a moment. As another member has stated, these are not RF Mosfets. They are some sort of rebranded/repackaged switching Mosfets that were most likely meant for power supply operation of a couple hundred kilohertz at best. I have yet to see any actual legitimate lab-style...

If it was only that simple to replace a bipolar with a Mosfet... I have no experience with the HG parts. In fact I didn't know they existed. Let us know how it goes if you use those. Also, a scope is better than no scope. You can at least make sure the modulation level is set correctly.

I posted about this in your other thread also. You will be much happier spending the money on the original parts. The Mosfet conversions almost never, "just work," and usually require a good amount of tweaking if you want a clean RF signal and a clean audio envelope. It's a lot of time, for no...