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On my QMX (mid-band), I can hear a constant tone on some frequencies, as if someone is tuning up an antenna, but it just stays. It also doesn't make a difference if I have an antenna attached or not,

To add to Bojan's comments a bit. Using a radio like the U3S, which creates the "data" through direct frequency control, you set the frequency to the actual Tx frequency. In Bojan's example 14.097130

Thank you for that very practical tip, given how low cost these little relays are, it's probably best to carry out that seperation as you suggest - I;ve never built an RF amplifier before, so all

One area is that input and output must not be close as in using the same relay. If isolation is not enough oscillation can be a unwanted result. I make it a point of using separate relays to get

Useful tip, thank you Peter - GM8JCF

? Tnx for the tip Peter - GM8JCF

Hi Barb Thank you very much indeed, really detailed instructions, very much appreciated. 73 Peter - GM8JCF

Hi Peter, Here is my take of QRPL linear 10W PA which I use with my usdx trx. I thought this might be a helpful guide for

Robert, first, I would check for a bad solder connection on the T507, especially on the grounded side of each 10T winding. Also insure that the number of turns on one side is identical to the number

my back of envelope calcs show that if you use four pole filters and chose the correct break point for the 5 Mhz filter at about 8.5 Mhz you can put in a no switched filter set for 60- 40- 30 mtrs and

Hey guys, I just finished building my QMX a week ago and bought a dummy load to do some testing. when connecting the dummy load to the QMX was getting a SWR on most bands (10+ at the highest and 3.3

Use a contact from Relay one ?as a the input controller for the RF use a contact from Relay 2 as the output controller for RF out. ?Currently you have RF in and RF out in the same relay. Some

In the message menu are interval and repeat set to zero?

Thank U Allison, it is tempting to add a set of the QRP Labs low pass filters so as to make a fully standalone 10W Linear Amp; something to think about indeed. Once again, thank you Peter - GM8JCF

Q202 and Q201 are the bias regulator for the drivers Q203 and Q204. Q206 is for Transmit enable (enables bias to the amplifier transistors). -- Allison ------------------ Post online only, direct

A bad pot could be the case. Especially true if one varies differently than the other. I've not found the bias to be "jumpy" or all that sensitive in adjustment for mine (N=5). The bias does increase

That should do what you desire. One note if you go direct to antenna (not using the BLA-amp) from the QRPL amp a set of low pass filters are needed. Driving the amp that is not

George- Thanks for your suggestion. I did delete the entire message #2, then replayed it, but the issue remains even after cycling the rig. ————————- Jim N7RCS Palm Bay, FL

Hi Steve, thanks for the input. I've checked the desoldered IC, the several supply to ground resistances showing normal values in the kOkm range. I should get my replacement PCM1804 end of next week,

And 24 hours later, it's still standing. So this tape can handle it and is approved for this usage :-) The 3D design of this tilt feet can be accessed through my website (