I have acquired a 20m QCX that dates back to 2017 on the PCB, there is also "2" directly under the date. The QCX powers up and the display and menu topics all appear to work OK. Upon turning the

If the rig is running full power to the dummy load I would look at your coax. Place the dummy load at the end of the cable and see if the loss for the length is within spec. If your able to realize

Hi, Bernard Lets see - 19.2 volts divided by 2 pi (convert to RMS) equals 6.79 volts RMS. Power is E squared over R, so it's 46.1041 divided by 50, or a skosh less than a watt. Of

19.2V peak would give you 3.7W. But if it was peak-to-peak then you need to divide the power by 4 giving 0.92W. -- 73 Richard G4TGJ

Here is a link to a site with the formulas to convert from pea to peak to

More like .92 Watts. Can you show your math? Jerry KI4IO

I keyed my QCX into a dummy load and measure peak-to-peak voltage with an oscilloscope across the dummy load. It was 19.2 volts, peak-to-peak. I think this means my QCX is putting out a little under

Hi, Matt First - 2 swr meters. If the swr meters are, like mine, ones made for CB, they probably won't show full scale on 80 meters, and possibly 40, with a 5 watt rig. I had to disconnect the linear

Depending on the accuracy of your voltmeter, and assuming this voltage reading was when you were in receive, this means that when you go to transmit, the voltage would likely drop below minimum levels

I test with the MFJ cub first because it is only 1W and my least used rig. It is pretty analog so easier to fix in the event I blow something up than the QCX. Battery is on charge now. I will check

That could be it too, but if the antenna is the problem be really, really careful so as not to blow the finals in the QCX. My Tarheel looked good in a similar fashion but it was connected by a "hair'

Hi, Paul Sounds like you have the pot rotated 120 degrees in the board, and have the 5 volt supply between the wiper and one end of rotation. Either that or you have pin 3 and pin 2

Hi Matthew: You say the battery is showing 12v...that sounds suspiciously close to 'flat'. Try putting your voltmeter on the power connections to the QCX, say, and see what happens when you key

Matt I think your battery is likely ok. If the rig transmits into a dummy load and you see that on your swr meter, it would seem that your antenna is the issue. Maybe there is a short in a connector

Sounds like a bad battery. SLA batteries can do what you describe. It can even show a false charge. I changed over to Lithium.

Hi, John Try the SN74CBT3253CDR from DigiKey, stock number 296-19206-1ND which is 16 pin SOIC 5 volt, at a horrendous price of 60 cents. Since they have 5998 in stock they won't be

I am hoping someone here can help me out, I am at my wits end. I have 3 QRP rigs, 2 QCX’s and an MFJ cub. I have 2 SWR meters I have a EFHW long wire with 49:1 balun I have QRP-labs 10W dummy

https://www.ebay.com/itm/FST3253MX-MUX-DEMUX-DUAL-4-1-TTL-16SOIC-UK-COMPANY-SINCE1983-NIKKO/192968115850?hash=item2cedcbc68a:g:VM4AAOSwzIJdF4wl Here are some from th U.K. John… Good luck

I’m in the process of modelling a custom 3D Printed GPS connector with dust cover. If anyone has a wish list or input at this stage then please share it. Scot 2E0WWV

This seems to indicate a short between pins 2, 3 of R47. It is shorting the 5V line to ground. 73 Alan G4ZFQ