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Same stage gains mentioned in dB found here on the homebrew UBITX receiver where I measured each 50 ohm block separately with a 50 ohm termination, except that I’m using a 45 MHz LC filter with 3-4

thanks gilles but i have decided to go for a gsx rig from qrplabs terry

ubitx on 7.152 signal generator set to 11.9962 3.5v got about 80mv p-p TP17

Ooops I think I didn't do it right for TP14 and 17.? My signal generator only goes to 25MHZ so couldn't do TP14. I can retry tp 17. I was testing at 7.150MHZ in general otherwise.

Took off the attenuator and measured at tp 13 took 200mv to get to .1vp-p tp14 took 1.4v to get to .1 vp-p tp17 3.5v only got to 30mv p-p tp16 3.5v only got to 50mv p-p

Forgot? T2 at about 2850 uV got to .1 vp-p

Similar to Jim's measurements These are approximate since I don't have equipment that can measure to microvolts - I estimated based on my max volts into my attenuator and calculating the lower

Frankly, I would not mind seeing other measurements ...at least to form SOME sort of baseline ...As I said ...Quick and dirty Don't like 'em ..delete 'em ....Measure your own and share There has been

Just and update. There was a whine that on the radio The bfo was off by about 2000 hz. I copied the bfo frequency off of one of my other machines and it only needed a small touch up from there.

Perhaps 1 or 2 dB loss through the LPF at L1,2,3,4 ? 6dB loss through the mixers ? Maybe 3 or 4 dB loss through the two crystal filters ? And around 10 or 12 dB gain through the 45mhz amp, 16dB

Wow thanks everyone for all of the great info and ideas to investigate this further.? Some great details and avenues to investigate further. I am using the stock software.? (A separate thread I need

Assuming your signal generator can correctly inject the levels shown in the chart, you should get rational results here regardless of the different frequencies. Namely,? ? Perhaps 1 or 2 dB loss

On second glance, those measurements show a 30 dB loss from TP16 to TP17, not a gain. Also a 20 dB gain from TP14 to TP16, going through the 45mhz filter and D3,4 mixer. That one should be on the

different frequencies .... Jim

Hi, I have not looked at the schematic. This problem reminds me of the failure I found in the front end of a different radio. There was indeed a broken winding on one of the inductors, one of those

I'm not sure what to make of Jim's measurements. YMMV indeed! Two measurements at TP1 with a difference of 30dB? Somewhere between 10 and 20 dB of gain or loss from TP2 to TP1, depending on which TP1

So ....What I did on my "seasonal vacation" Quick and dirty trace thru V3 ubitx ...Test points correspond to V4 locations ... Set ubitx freq to 7.152 mhz dial indication ...Maybe off a little as WWV?

I read (and had the issue myself) where the USB and LSB seem to get reversed.? This was related to the LO being off.? It was solved for me by going back to the default after setting the BFO and then

Actually I redid the BFO adjustment to zerobeat and at 11996.6 sounds better for 1khz, and at least the conversations are intelligible better now.? So that is a bonus. (conversation is still faint)

Thanks I see as folks suggested? Q10 is past the first mixer of clk2.? That still doesn't explain why injecting at L4 is heard significantly less than injecting at L1.? I would think the closer I