Jim's questions and stability queries...

Ashhar Farhan <farhan@...>
 

jim,

there would be far less stability problems if you built modular style!!
you will have better isolation and the manhattan style also provides
a ground plane for excellent stability.

that said, i think i need to clarify somethings about the PA stability
problems.

ours is an open project that is largely driven by the community of builders
rather than
a single person or organization. hence, there is a difference between how
issues are raised and
resolved here.

to begin with, let me say that the bitx's PA stability issues are not
serious. It is, in fact, one of the more stable power amplifier line ups out
there. every stage has negative feedback except the power amplifier and they
are all individually stable.

If we had mandated a single type of construction, same type of enclosure,
power supply etc, we would have got repeatable performance from each build.

however, ours is a different approach, a quick look at the group's photo
section will reveal that everything from altoid tin boxes to boat anchors
have been tried as enclosures. constructions have ranged from professionally
done PCBs to rat's nest wirings.

the most redeeming feature of bitx is every one of them finally works. this
is not due to any particular magic of circutry, but the nature of the
project. it is one of the most well understood homebrew projects, several
hams with years of experience like leonard, dan, arv, etc. have worked for
days at it, understanding the nuances and making us aware of the issues, and
solving them.

like any other open source project, you will find several people pointing
out to issues and others solving them. that doesn't mean that this project
has more issues than others. it is a testament to the culture of enquiry and
elmering that ham radio has stood for.

- farhan

On Feb 8, 2008 4:15 AM, JShroomy <@ab9lm> wrote:

Hello all.
I've been looking for such a transceiver project for a while, and
finally came across the BITX20.
So far I've found about 50% of the components needed, and getting ready
to order the other half from mouser.
I've built several kits before including an ATS3A which were all
flawless, so I'm a pretty experienced kit builder, and not so much
a "from-scratcher".
I'm planning to build it manhattan style using the schematic from
Hendricks kits.
For now, I'm wondering if there are any RF/stability issues I might
encounter by building this in a modular fashion. I was wanting to build
each section on its own small board, and then join them all together as
I go along. Are there any issues w/ building this design in that style?
Is regular hookup wire sufficient to join module connections, or is
there a benefit to using shielded rg174, etc.
I'm really looking forward to taking on this project as my first
scratch built radio.
Thanks in advance,
Jim - AB9LM


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