Date: 28-07-2003 	User comment 	From: Bill - KC2NG
    <mailto:kc2ng@fingerlakesrepair.com.MODIFICATION.NET>
    Subject: Filter Re-Mapping for 60 meter band use

    Here is one proven way to get use of the new 60 meter band without
    resorting to an external switch.

    As you know from previous posts that you cannot operate the Pro and
    Pro2 in the 60 meter band because of output filter losses. I wanted
    to be able to use my Pro2 on the new band and did not want want a
    switch sticking out of the case.

    The issue is that the 3.5 MHz lowpass is selected from 3 to 6 MHz.

    The first thing I tried was to force the selection of the 7 MHz
    filter. This worked fine for the new band but did not allow for
    operation on 80 meters. Not an acceptable solution.

    What was needed was a way to select the 7 MHz filter only when
    operating above the 80 meter band. Fortunately there is another goup
    of filters in the pro2 that have filter mappings we can use. The BPF
    board has a filter for 2-3,3-4,4-6 and 6-8 MHz. This allows me to
    re-map the band selection frequencies to select the 7 MHz filter
    from 4 to 8 MHz.

    There is a small price to pay for the new band. Operation from 4.0
    to about 4.5 MHz is not recomended due to filter insertion loss. I
    measure 89 watts out on mine at 4.0 MHz. Operation from 3.0 to 4.0
    is normal.


    The mod is as follows:

    Parts required: 4 diodes (1N4454 or equiv) some small gauge wire.

    On the BPF daughterboard, connect a diode to pads B2, B3, B4 and B5
    with the anode connected to the pad. Connect the cathodes of the B2
    and B3 diodes together. Same with the B4 and B5 pair. The output of
    the B2-B3 pair is the control signal for the 80 Meter output filter
    and the B4-B5 pair is the 40 Meter filter.

    On the Filter Unit, top side of the board near the relays RL4 and
    RL6 are two 0 ohm jumpers W2 and W6. Remove them. There are 2 larger
    pads next to each of those jumpers with nothing installed on them.
    One of the pads goes to the relays RL4 and RL6.

    Run a wire from the B2-B3 diode pair to the pad to RL4 and run a
    wire from the other pair to the RL6 pad. Be sure to route the wires
    along the edge of the Filter unit and tape them down. You want to
    minimize the RF picked up on the wiring. I found the only place to
    run the wires is thru the opening in front of the fan. Carefully
    install the covers and power up the radio and enjoy the new band.

    If you have any questions or would like assistance with the mod,
    please contact me at the email address above.

    Bill - kc2ng@fingerlakesrepair.com