OK, you guys are getting serious.
I'm moving the discussion back into the power chain thread so I can find stuff later.?
In post? ??
/g/BITX20/message/51743? ?Allison mentioned 2n5109's
for the driver and pre-driver,? BFR106's for the low power SOT-23 slots.
Cost is comparable to 2n2222a's and the MMBT3904's.
Is there a reason not to use the 2n5109's in the driver and pre-driver, the BFR106 at Q90?
Perhaps board layout will cause these parts to oscillate somewhere up in VHF??
Could also use the BFR106's in the 45mhz IF BiDi amp, both directions.
On the transmit side it might solve the mixer spurs that Allison was beating her head against?
And on the receive side, can't we use more gain at 30mhz?
Here's the three pertinent posts from the "Topic change" thread:
#############? ? HISTORY? FROM???
/g/BITX20/topic/22395047? #################
I tried a BFR93a (because i had some) for Q90 which seems to work OK.??glenn vk3pe
Jerry,This a topic change???I put the TX aside for a bit to deal with life, garden, and play with the receiver.Generally the TX power thing is a hard nut to crack with the physical constraints?and high required gains.? I'll get back to it.?Where we left off...Oddly dealing with two other uBITX the simple steps are the good enough.Those being Farhan's C81 mod (470PF), my better transistor in that spot(BFR106),?and swap out the 3904s with 2n2222A(TO18), add the SMT choke at R86.? More?than that is seriously involved.? For 80 though 17 it really helped and improved 10M.For most that solves most of their wishes.One hint: mount all the 2n2222A(to18) from the underside with short leads as that?is easier and opens up the top side for better airflow.?Allison
Good luck getting several thousand forum members to agree when it's appropriate to start a new thread.Perhaps if it's "your" thread and you feel invaded, then a polite suggestion might be warranted.?I wouldn't bother.?Speaking of which, where are we at on those mods for the final amp?Jerry, KE7ER
