[ARC5] ARC-5 T-20 Frequency coverage and other questions

[AKLDGUY .]

> Moving the MO down a full MC would not give you KC-for-KC dial
calibration.   As you go up or down in frequency, the
> change per degree of rotation also changes.
> The T-20 covers 1300 KC for a full rotation.
> The T-19 covers only 1000, so your dial calibration would not track over
even a short range.
>
> I have moved T-20 and BC-457 down to 80 mtrs before
> but don't remember how much I changed the MO cap
> or the PA padder.  I do remember I removed the lock screws
> and I could move the MO down enough with a small screw
> driver through the hole on the side, so it didn't need to go "full mesh."
 Neither did the PA padder. I put 4 MC at the "top"
> end of the scale and made a "tuning chart."  Worked well.
>
> GL OM ES 73 DE Dave AB5S


Hi Dave

Sorry for the long delay in replying (due to time zone difference and
commitments during the day).

That is how I remember it. A basic retune to 80m (but with NO provision for
tracking) is a simple matter of shifting both the padding capacitors (what
I called the bandset capacitors). No rewinding of coils or other drastic
mods.

73 de Neil ZL1ANM


On Fri, Aug 1, 2014 at 12:06 AM, David Stinson <arc5 at ix.netcom.com> wrote:

> Moving the MO down a full MC would not give you KC-for-KC dial
> calibration.   As you go up or down in frequency, the change per degree of
> rotation also changes.
> The T-20 covers 1300 KC for a full rotation.
> The T-19 covers only 1000, so your dial calibration would not track over
> even a short range.
>
> I have moved T-20 and BC-457 down to 80 mtrs before
> but don't remember how much I changed the MO cap
> or the PA padder.  I do remember I removed the lock screws
> and I could move the MO down enough with a small screw
> driver through the hole on the side, so it didn't need to go "full mesh."
>  Neither did the PA padder. I put 4 MC at the "top" end of the scale and
> made a "tuning chart."  Worked well.
>
> GL OM ES 73 DE Dave AB5S
>
>