JUMA Amateur Radio Forum

Hi Adrian! Thank you for your quick answer. I have been so busy that I have not had time for answering so far. You are fully right and I old fashion! :D I have already agreed with one hammate that he helps me uploading the new software which you shared for me. When the case is closed I will give ...

Hi! I assembled own Juma two years ago and have used it very satisfied. So far I have used cw only, but now couple of time tested ssb also. With ssb I have met problems time to time because SWR seems to be too high (even it is not) and output goes down. Then I remembered that somebody spoke about ...

Hi All! My problems with Juma are history now or have been history long time already. I have only forgotten inform what has happened. So Juma has been in use couple of months and personally I am more than delighted customer! :D When I did my last fixing I did an error: I bought new TR3 and 4 but ...

Hi Robert!

Thank you for your hint! But I suppose that contamination is more optical illusion than truth. The most probably error is contamination between my ears.

My Juma is now “in better hands” and let see what he will find for the root cause of my problems.


73, Saku OH2NOS

I have been out of hobby last month, but now I have time again. I have still the problem that my Juma TRX2A doesn’t work. Before when I listened, I heard nothing even I added gain. 1) Then I decided to change TR3 because I assumed it been defected, because nothing happened when I pressed tangent d ...

Hi Matti! Yesterday I made couple of measurements based on Main board voltage table (Appendix E). Now I have checked receive state only (Mode LSB, f = 3.7 MHz, Filter WID, AGC slow, Speechproc OFF, NB OFF, MIC input, dummy load). Here I present findings which are not according to the table. OPAMP ...

Hi Matti! I have been out of hobby last two weeks, but now I inform that 10V line is up and running. When A10 and A11 was turned in correct position output voltage of REG 2 was 10,2V (or 10,3V), but anyway the reason of problem was wrong position of A10 and A11. I make more stupid question for ...

Hi Matti! I checked the Filter 1, its resistance between pins 2 to 3/4 is 7,2 kohm. Previous measurements I made with pure Main Board without Filter 1. The whole resistance, when Filter 1 is connected, between C64 (+) and ground is 3,9 kohm. Then I checked A1 to A11 with magnifying glass against ...

Hi Matti! I have good and bad news for you - bad first! I have not been able to fix the problem with 10V power supply. Good news is that I have done lot of measurement for tackling the problem but without success. Measurements which I have used are Fluke 179 Multimeter and Fluke 105B Scopemeter. 1 ...

Hi Juha! Life goes on but some problems stay. Some progress has happened. First, I downloaded datasheet of LP2950 (2951). Now I got better understanding about pins and their meaning. Reg 1: Pin 2 was badly soldered and it is now connected to pin 1 and the regulator works correct! Output voltage is 5 ...