[FoxHunt] RX1 PLL MOD

[Gerald Boyd]

The Albuquerque transmitter hunting group has been using an add on board =
for the RX1 ARDF receiver for some time now.

The board is called OZMOD (see =
http://home.att.net/~wb8wfk/equipment.html#ozmod  ) our group now has =
artwork for version 3 of the design ready for FAB.

We are going to send the order to the board FAB shop soon.=20

Because Ozmod makes the RX1 very stable this has allowed our group to =
make another modification to the RX1.  About a year ago we modified the =
high IF in the RX1 to use a narrow band crystal filter. This eliminated =
a problem that we were encountering from an active mountain top voice =
repeater and a local APRS repeater. The APRS repeater was about 2 miles =
from our ARDF site and 1.175 Mhz below our hunt frequency! The original =
RX1 uses a wide if filter (FM broadcast type?) in the high IF. No more =
APRS and long winded QSO QRM encountered during our ARDF sessions.

OZMOD also extends the operating time of the RX1. This is because OZMOD =
is using a DC to DC converter to generate the required operating voltage =
for the RX1 and the PLL controller from 4 AA 1.25V size nickel metal =
hydride cells. We can now operate several ARDF practice sessions on a =
single charge. If the receiver gets turned on during impound no problem.

OZMOD also provides two VFO's that can be selected at a push of a single =
button. One is for the FOX and the second is for the finish line =
transmitter. They can be reprogrammed in the field and saved to NV =
memory to accommodate your event. An on course timer, ARDF cycle timer =
and system voltage monitor is also provided on the LCD display.

Currently we have about 12 persons wanting boards, because of the NRE =
charge each board will cost around $30 each ( PCB board only) the more =
boards we can get on the order drives down the cost.=20

The boards are high quality with solder mask and screen with plated =
through holes ( V2.0 OZMOD photo on web site URL). A majority of the =
parts are surface mount. Parts can be ordered from the internet from =
Digikey and Newark.


When I have the final head count for boards I will go get an estimate =
from the FAB shop which will determine the actual cost.


Jerry Boyd, WB8WFK


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