T1 on JUMA TX-1
Posted: 12 Jul 2021 15:01Dear other hams
I was wondering if it's possible to substitute T1 on TX-1 with something self made?
On RX-1 this TDK transformer has been substituted with this:
http://www.jumaradio.com/juma-rx1/bifil ... er-en.html
I did similar also for TX-1, BN43-2402 with four turns of bifilar coil. I was able to bias the PA correctly (5mA+5mA per side and 100mA for driver) but somehow I just can't get enough output power even if I max out the RF gain. Test bench showed only around 1,2 watts on 3,5MHz.
Could this be due by self made transformer? Or should I tweak C6? I'm planning to get Kemet's replacement for TDK ZJYS51R5 since TDK is obsolete.
I was wondering if it's possible to substitute T1 on TX-1 with something self made?
On RX-1 this TDK transformer has been substituted with this:
http://www.jumaradio.com/juma-rx1/bifil ... er-en.html
I did similar also for TX-1, BN43-2402 with four turns of bifilar coil. I was able to bias the PA correctly (5mA+5mA per side and 100mA for driver) but somehow I just can't get enough output power even if I max out the RF gain. Test bench showed only around 1,2 watts on 3,5MHz.
Could this be due by self made transformer? Or should I tweak C6? I'm planning to get Kemet's replacement for TDK ZJYS51R5 since TDK is obsolete.