On Sun, Mar 12, 2023 at 04:52 PM, ajparent1/kb1gmx wrote: thermistor on the finals that pulls down the bias. Perhaps a forward-biased diode (or BJT emitter-base junction), thermally-coupled to the out

#10W_PA

Two possible things one being a fan (quiet) to move air on the heatsinks as that will help cool it. Let me guess FT8 or similar, very hard on all power stages due to 13 second full power tx and 17 sec

#10W_PA

I am using my 10W linear PA at +12.6V supply. The basic current is 360mA. This includes both built-in units the RX/TX relay and the LPF switch board. After operating at continuous 10W RF output power

#10W_PA

My 2nd 10W Linear PA draws about 5 mA when !TX is not connected, which rises to about 80 mA when I ground !TX, enabling bias on the first pair of transistors. Per the instructions I then added another

#10W_PA

I started testing it with an 10:1 voltage attenuator at the input. The U3S gave 1.0W, 10 mW probably got into the PA, and 300 mW came out. 15 dB gain was less than I expected, but usable. I removed th

#10W_PA

It is really a good 10W HF PA. In my case it has 20dB gain as I added a 6dB attenuator to the input to improve the RL. I have checked the consumption at +12.6V DC supply now. From 14MHz to 28MHz with

#10W_PA

1.2A is a little low for a linear amplifier. I can't conveniently measure it right now, but most of them run around 30% efficient in some modes. I know I need to fuse mine at 3A for 13.6V or I eventua

#10W_PA

True. This is a 26dB linear amplifier. So, you need a 25mW to 50mW signal max at the input, depends on the frequency. I would say the max DC current at 10W output would be 1.2A? 73 Bojan S53DZ

#10W_PA

The 10w Linear PA is a high gain amplifier. If you are connecting it to the output of your U3S then you will probably need an attenuator of about 6-10db between your U3S and the linear amp to prevent

#10W_PA

I'm setting up my second U3S with 10W linear PA. It worked for a little while - until it smoked the PCB foils between the IRF510 drains and the output transformer. Its current consumption was 2.5A at

#10W_PA

On Fri, Jan 27, 2023 at 07:36 AM, bojan.naglic wrote: Hi, The 26dB 10W linear PA has nothing to switch between Rx and Tx. It has to be added. The ~10dB (QCX) 50W PA has a diode Tx/Rx switch built in.

#10W_PA

Since it was designed to be embedded those thing would either be there in a TRX design or needs to be added. To that also LPF.

#10W_PA

Hi, The 26dB 10W linear PA has nothing to switch between Rx and Tx. It has to be added. The ~10dB (QCX) 50W PA has a diode Tx/Rx switch built in. 73 Bojan S53DZ

#10W_PA

I have never looked at the 10w amplifier's antenna section but I have a question... does it not pass RF from the antenna back to the radio when not keyed? The 50w amplifier does not require any relay

#10W_PA

good afternoon everyone, reading your emails and seeing the diagram in the figure I think that the 10 W PA could also be used on the qcx mini! Could someone possibly send the diagram to be able to red

#10W_PA

Actually, NO, this probably needs to be an 'external' group-project with boards/semi-parts kits (JBLC, FAR Circuits) - stay tuned!

#10W_PA

Thanks Collin and Peter for your advice! Sure the dummy load will give me some confidence. I was even thinking of assembling a QDX, I guess it is more forgiving. I will keep you updated on my progress

#10W_PA #20m

On Wed, Jan 18, 2023 at 06:50 AM, EA3IKB wrote: I there! I have been lurking in this forum for a while. Truly interesting posts and info. I am the happy owner of a QCX mini 20m. I bought it built as m

#10W_PA #20m

The mechanical assembly of the mini takes some patience. It’s best if you fully understand how the case and screen fit together before you start. However, if you follow the directions carefully and ho

#10W_PA #20m

I there! I have been lurking in this forum for a while. Truly interesting posts and info. I am the happy owner of a QCX mini 20m. I bought it built as my soldering skills are very rusty and I don’t ha

#10W_PA #20m