Dave, IC9 Pin1 is the last stage before the volume pot. The only thing between the 2 is a capacitor, C21. Perhaps something at that stage is incorrect. Take a look at C19, C20, R34 or R35.

Bill, Thank you so much for your reply. I will do all of this after work tonight and mark it off on the circuit diagram! I have looked real hard at the board and can't see a break or hair, but will

Dear Group, I have finished my QCX 40m kit, but I'm having a problem with the audio out. I can hear the receiver, and the BPF on 8.7 measures a solid 8 with an audible tone, but barely audible

Hello Matthew Make your own dope out of toluene and polystyrene. Use a small amount of toluene +/- 100 milliliters and add lots of polystyrene to the liquid. The viscous will eventually change and

selling my 40 meter qcx radio mounted in the bamatech case comes with the QCX 50 watt amp mounted in the case. Both are in good working condition and built in the past 2 weeks. If you have any

SOLD. -- John AE5X https://ae5x.blogspot.com

Thanks folks - the case has been sold. 73, -- John AE5X https://ae5x.blogspot.com

Keep away from any sealant that has a acetic smell which is like vinegar. It will corrode copper wires in a few weeks / months. Two part epoxy resin is good but don't use too much and make

John . . . I would like to purchase the BamaTech enclosure. Please contact me at my call @bellsouth.net. Thanks, Paul W4KLY

I have a BamaTech case, button extensions and all associated hardware for sale. The housing has never been used. Here are descriptions of the

Hot glue verses coil spacing This is my multi band (no T1) QCX with 30 m LPF installed NOTE spacing between turns, out put now greater than four Watts When spacing was equal and pretty, out put was

John WA8US 3 to 6 years ago there was some interest and action using LTSpice to verify operation of various parts of the original BITX and similar units. Results were quite good, even though some

I haven't, but years ago I modeled many of Dave Benson's QRP rigs. A far better choice for a hobbyist is LTspice offered free by Analog Devices on their website. Naturally, it is

Matt In rigs where an inductor is part of a VFO - keeping the turns in place is vital. The QCX does not have any circuits where things are this critical. Okay maybe except for the coil with all the

Matt, When I worked for a uk company manufacturing wireless microphone systems used in both broadcast and London's West End we always used hot glue to stabilise inductors. Why? It's easily re-workable

Has anyone simulated any of the QCX circuits with software like PSpice? John WA8US

K2DB Paul Mackanos wrote on 2/27/2020 10:29 AM: Hello-- This doesn't apply to QRPLab's toroids, but years ago I worked for a company that built epoxy-encapsulated modules, one flavor of which

My vote is for Blue Tack. Here's some I used on a 630m LPF using Mix 1 toroids to save space and turns count. 73, --Al

A drop or two of instant glue on each side of the toroid works very well for me. Paul K2DB

Yes. When whatever you have applied to the toroid cures or dries it can cause the wires to move or shift ever so slightly which can change the inductance a wee tiny bit but not enough that I have