Don't worry. My QDX Rev.3 also draws 140mA at receive. This is perfectly OK according to Hans. There are more OP-amps in Rev.3 and the new A/D converter has higher consumption as well. I'm sure Hans w

A bit off topic since this was not done with a QRP-Labs kit, but, anyway: Slow CW TX on 20 meters, 14.10111 MHz. Three 74HC00 gates in parallel as "PA", the fourth gate is used for keying. 5mW output

#amazing #contest #power #poll #qcx

Hi, BS170 is a normal enhancement mode N-channel MOSFET. Vgs = 0 => zero drain current. 73 Johan SM6LKM Den 2022-06-23 kl. 17:02, skrev Donald Giles:

Hi, QDX transmits a constant-envelope single signal so the amp' that follows it doesn't have to be linear. Some digital modes need linear amplification, for sure, but not those modes that are compatib

#qdx

Well, it could be software related in a way, but not a problem/error. Check that 20m and 30m transmit are enabled in the terminal configuration settings. 73 SM6LKM howard winwood G4GPF wrote:

Hi JS8Call starts up on 7074 because it polls the current VFO frequency from the radio. Factory default start-up frequency is 7074 on QDX but that can be changed in the QDX configuration settings. It

Hi ON4AA has very good info on DIY 6-band OCFD antennas here: https://hamwaves.com Look for Multiband HF Center-Loaded OCFDs 73 SM6LKM

I bought 100 BS170 here a few days ago: https://www.electrokit.com/en/ 73 Johan SM6LKM Den 2022-05-27 kl. 18:23, skrev Joshua KJ7LVZ:

Any distance between 0 and 500km (or so..) is the "NVIS territory". The original post also mentions a mountain which may block VHF/UHF line-of-sight signals so HF NVIS could be a very good alternative

#qdx

You have to wait for the status to change from "Complete" to "Shipped". 73 SM6LKM jsternmd wrote:

Thanks for the information Robin. I didn't know about the HB9AW beacon. It is loud and clear on this web RX http://bachtel.dyndns-remote.com/ about 60km away from the TX. 73 de Johan SM6LKM HB9DEF Rob

#qdx

Tom, for NVIS (short distance HF communication) you should look at foF2, the "critical frequency". This is the highest frequency that the F-layer(s) is able to reflect vertically at a given point in t

#qdx

Choose a serial port and set its parameters under Category/Serial: Choose connection type Serial under Category/Session: You can save the settings for later use by typing a name, for example U4B, in "

#u4b

I forgot to say that you'll need to logout/login (or reboot) for the change to take effect. You can list the groups that you are a member of with the command groups pi 73 SM6LKM I wrote:

#u4b

Hi Mike, you may need to add yourself to the dialout group in Linux to get permission to use serial ports. In a (Linux) termninal window, try this: sudo usermod -a -G dialout username where username i

#u4b

Pat wrote: 73 de SM6LKM

Murat, you could try a full wave loop which uses less space than a dipole. It has slightly more gain than a dipole, about 1 to 2 dB or so. Examples: https://pa0fri.home.xs4all.nl/Ant/Quad/quadeng.htm

#15m

Nice work Glenn! Just a word of caution, since it it a Rev1 QDX, make sure that you have upgraded to firmware 1.02 or later. Earlier versions had a problem that can cause catastrophic TX failure. 73 J

Julian, yes that's 0.75W but it is reactive power, not real power! Assuming 20Vrms of RF across L11, and +j531 ohms reactance (2*Pi*1.8MHz*47uH) the RF current is no more than 20/531 = 38mA rms. Assum

#qdx

Hi, correct, the bias circuit has nothing to do with the BPF resonance. Double-check the total number of turns on L12 (all turns are used on 80m) and, if that's correct, check C30 (220pF) which resona

#qdx