Recent content by CommandoTech

Changes to values in the service menu can be done while pushing the PTT button and holding it while using the up/down channel buttons to change values. The setting you might be interested in is the RSSI (Received Signal Strength Indicator) menu setting. Hope this helps.

Awesome. Can't leave a good radio like that unrepaired!

Very welcome and good luck.

The missing trace does not appear to connect to board ground. Here is the area in question. The trace connects R503 to C534 which is tx audio in to the 4558 op amp.

I would stay somewhere in the vicinity of 65-75 ma max 100 is the danger zone.

I wonder why the manufacturers didn't incorporate a feedback circuit similar to the Cobra 148GTL driver stage? And I agree with loosecannon on watching your current draw on each device. If you go over 100 milliamps idle current on mosfets things can go badly quick.

As a side note the same gentleman who owns that amp just bought a 2 mosfet kit and is having me build it. I like the well laid out design of the board and the biasing circuit is spot on.

@$1.60 each in lots of 10 I meant. I hope there's enough room to rewind the combiners to 3 phase lol.

I just priced small lots of the FDA24N40Fs at $1.60 in lots of 10. The amp is still working flawlessly. The gentleman who owns the amp wants to add the extra 2 mosfets and make it a straight 6.

I happen to have an amp here that has 4 of the above mentioned mosfets installed. It is producing the right amount of power and I have checked it on the spectrum analyzer and it has a clean output.

The 24N40F Mosfet can be used as a substitute for the ERF7530 / ERF9530.

If anyone is curious about a replacement for the ERF9530 Mosfets try the FDA24N40F.

Thank you Sir and yes this is the place if you are seeking information on anything RF related. You have a cadre of seasoned professional technicians here and I hope to learn as well as contribute to the best of my ability.

Yes I agree with the above facts that mosfets are primarily for switching applications and are certainly not "bullet proof", in fact they can fail spectacularly (aka grenade). However with the proper installation, care and feeding they can be used in an RF application. I currently have a Cobra...

I have extensively tested several different types of mosfets in a variety of radios and have found them to be consistently able to not only to withstand the stresses but also exceed the performance of bipolar transistors. You can easily replace those 1307s and get exceptional performance from...