JUMA Amateur Radio Forum

I have been assisting some amateurs who have noticed that C27/220pF capacitor in the 10m output filter gets excessively hot and eventually fails. IMG_0727.JPG The above image shows this effect in my amplifier after tuning the amplifier into a dummy load for a short time. I have discussed this with M...

There is now a new version of the Juma TRX-2 firmware, version 1.09a, which adds a new feature. For full details, please see the section of the website related to my firmware.
Adrian, 5B4AIY

The latest version available from this website is v1.05h Build 12 which fixes a bug. There is now a new version of my firmware for the Juma PA-100D. the principal feature addition is that it is now compatible with the Elecraft KX3 Ultra-Portable HF Transceiver. It will work with this transceiver in ...

Hi, Bob, Thanks for the offer, let me think about that. I'm sure the TTL interface has survided its exposure to the Juma RS-232 port! The Juma port cannot suuply any real current, and equally even a TTL output stage cannot really harm the RS-232 input, so my guess is its fine. However, now that I'm ...

That would explian a lot! Anyway, please see my post: LDG Z-817 & The Juma TRX-2 Addendum.
73 Adrian, 5B4AIY

I use a very simple terminal program, SimpleTerm, (ZIP attached.) It works with Win-XP, Win-Vista, and Win-7 in the latter case, both the 32-bit and 64-bit versions. It does not install anything, simply launch the executable. I have used this terminal program for all the firmware development I did f...

There is now a slightly improved version of the firmware for the Juma TRX-2, version 1.07y Build 15. The only aspect visible to the user is related to the use of the LDG Electronics Z-817 QRP Automatic Antenna Tuner. The Yaesu CAT emulation function has now been modified to permit automatic operatio...

Hi, Dave, Glad to have been of some assistance. Most of the problems associated with the kits have indeed been missed soldered connections or open solder joints. The quality control is excellent, and there have been very very few bad components, especially if suitable anti-static precautions have be...

Hi, Dave, The reason your display brightness and contrast do not work suggests a problem with the PWM circuitry. The following explanation may help to understand how this section of the amplifier works. You will need to print out the schematic: Juma-PA100 Control Board CPU & LCD Sheet 2 of 2. Le...

Hi, Attila, This link should give you the modification information you require: http://www.nikkemedia.fi/juma-trx2/rev-b/trx2-line-in-mod.html In addition, you might like to consider using my alternative firmware when you have constructed the transceiver and it's working properly. You can download i...