Re: 5W Power Amp and the U3S; Options for a few watts

K2DB Paul Mackanos

Sam, or anyone else that would like it, I can take more detailed pictures and show you what I’m working on. I mounted two little 5 volt cooling fans on the bottom left rear of the enclosure, one blowing air in, and one blowing air out of the enclosure. I also epoxied a temperature sensor on the top part of the heat sink for the amplifier, and one externally on the rear panel. My goal is to use the DB nine connector, and hook up to my Clock to monitor the inside and outside temperature of the unit, And connect the external GPS antenna, with this sheltering in place I may finish it in another month or two 🤪 then again maybe tomorrow or the day after, who knows😎
Due to the fact that I have 160 m low pass filter installed, I had to extend the nylon spacers between the LPF board and the amp so that the coils did not short on the bottom of the amp board. I had to use slightly longer screws to fit the threads on the nylon insulator. I had to install the 160 m LPF on the relay board because the pins connecting the LPF  to the main board we’re not long enough to allow me to use it in the slot 0, So I mounted it in slot 5. I also had to use a shorter DC Power connector, because the heat sink would have shorted against the original connector.
Like I mentioned, if anybody wants me to take detailed pictures of the whole project I would be willing to do that. 😉
Paul K2DB

On Tue, Apr 14, 2020 at 1:03 PM K2DB Paul Mackanos via <> wrote:
If you play around a lot you can mount the GPS module upside down on the top part of the case with a 5 V power supply and it will all fit, it will just fit I’m still not finished.
Paul K2DB
You will have to run an external GPS antenna, I’ve got that in there temporarily but I’m gonna run it out to the DB nine connector.

On Tue, Apr 14, 2020 at 12:04 PM Samuel KJ4VPI <sernstfortin@...> wrote:
Will the 5W HF power amplifier fit in the U3S case? I saw I think in an application note AN004 that it could be mounted behind the Relay Board and the 5LPFs mounted to it. 

In my case (ha ha ha) I have the GPS module, because I am powering an external GPS antenna. So what I'd like to know... if I wished to retain the GPS board in the case, and presuming the 5W PA heatsink would collide with the GPS module, could I run wires to Q5 and Q7 and have the heatsink on the outside of the case?

Otherwise, if I wanted to try out a 2W external amp, all I have to do is remove a capacitor (C5) and route the RF off the board and back on at the indicated places in AN004, right?

73 Sam, KJ4VPI

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