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Ramsey DF-1:


This is a Ramsey DF-1, a vast improvement over the much more common simple switched-antenna design used
by so many fox-hunters. It switches in a similar way, but then processes the receiver audio much like a
doppler, and provides an EXACT bearing, as well as left-right indications.

The sensitivity is much lower than a tape beam, so keep that handy. But once you're in range of the
DF-1, definitely throw the beam in the trunk, this will greatly speed up your hunting. While it's
immune to overload, it can't sniff, so you have to be at least 3 feet away to get a bearing. This could
be a little problem if it's very well hidden, so bring a sniffer (field strength meter or tape beam with
offset attenuator) with you.

There are three fixes that need to be done to an original DF-1 to correct manufacturing/design mistakes,
see folder here for repair notes. Unfortunately, the board went through numerous revisions during its
production life, so you don't know what you've got until you open it up and examine the circuit board.

And since it's no longer available, I'm making a new one myself so others can benefit from the design.


circuit design

datasheets

DF-1 board defect repairs

DF-1 manual.pdf (569 KB)

DF-1 upgrades

N0ZYC DF-1+



last updated 11/30/2023 at 20:19:06