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Re: Easy mode A RX



If I remember right, there's also a pin on the 858 chip that converts it
to 5 kHZ channel spacing.  That cuts your highest frequency in half, of
course, so you'll definitely need a new crystal and channel switching
arrangement, but it makes the rig's tuning much more convenient.

Jim Shorney wrote:
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> 
> On Sat, 31 Jul 1999 22:28:29 -7, ka7hbb@janel.navicom.com wrote:
> 
> >Please note that the uPD858 usuallu only get up into the low 28 mhz
> >without a crystal change.
> 
> Absolutely not true.  There are one or two pins at the high end of the
> BCD code that are not used and tied to common.  It's been a while since
> I've done this, but the programming range of the uPD858 is capable of
> covering 26 to 30.  Of course, the radio is not broad enough to cover
> that entire range at once, but the PLL chip is capable.  I have
> modified several of these rigs over the years for 10/11 meter coverage,
> so I know of which I speak.  I had my mobile rig setup to cover 26.5 to
> 29.0 with no dropoff in performance except at the very edges, no gaps
> in coverage, and no crystal change was required.  There is even a mod
> for the TX circuits to make it more broadband.  The coolest mod is to
> replace the CB channel selector with a set of BCD thumbwheel switches
> so you can dial in your freq directly.  Of course, you can get more
> elaborate than that, but it was simple and easy, and there was a direct
> correlation between what the switches read and your operating
> frequency.
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