Re: bitx20 problems #bitx20help

Jerry Gaffke
 

That's a very long list of trouble.
And  a rather old Bitx design.
Most folks in this forum are now using either the Bitx40 or the uBitx from hfsignals.com.

> sometimes it all looks so simple. like you just build the simple circuit and you're done.
> But that is not my experience. 


Radio circuits are seldom simple to get working well, especially if you don't have
a couple thousand dollars worth of test gear and 40 years experience with it.
And sometimes, even when you do.
Even for stuff considerably more simple than your Bitx20.
A complete superhet SSB transceiver is definitely not simple,
though the Bitx design is getting close to being as simple as possible.

I suggest you get a $59 Bitx40 working, that might prove challenging enough:
  http://www.hfsignals.com/index.php/bitx40/ 

If you really want to get this older Bitx20 working, you need to tell us which set of 
instructions you are working from, what you did different, where you had questions,
post a few photos, describe the test gear you have at hand, and a full description
of each problem as you take them one at a time.  Assume months, given your
initial description. And likely involve at least having a DVM and a 10mhz scope
(preferably better) and something like the Antuino available to help debug it.
Just getting the crystal filter to behave properly and the VFO stable enough
may prove to be significant "learning opportunities".

Jerry, KE7ER    Flora OR



On Sun, Aug 18, 2019 at 11:04 AM, <driesbreughe@...> wrote:

I have been a radio amateur since 2007.
over the years I have made many contacts worldwide  using comercile radios like ts-450 and ic-703.
because that is the easy way.
nevertheless, I always thought that was a bit of cheating, a shared honor with icom and kenwood.
there is a lot to be found on the internet concerning homemade transceivers.
on some websites you see diagrams, explanations, photos.
sometimes it all looks so simple.
like you just build the simple circuit and you're done.
But that is not my experience. sometimes I think it's a bad design or I'm just a stupid builder
in 2012 i started building the bitx20. clean with a printed circuit board that I had made.
it was many years and failed project, But now I  want to make an attempt to finish it
the receiver works, but not completely clean. I hear many mixing frequency products.
the recipient was deaf. in ssb they were only very strong stations. who came through it.
the transmitter: almost no carrier suppression
the pre hf amplifier (q14) functions as an attenuator.
i am not sure regarding the rf transformers. TV balun core is a vague description. Can it also function well with a ft37-43?
i also built the hf amplifier with  6   2n2018 transistors.
i used an hf oscilator (ne602 with a bit of external gain) to test the hf amplifier.
there was power gain, I had 250mW not the expected 5W
it is not specified which diode it must be.
I managed to get a 1N4001 in it
I hope you can give some advice in the hope of resolving technical issues.

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