Can a Heath GD-1B be safely powered from a DC/AC power
inverter? I know the output of most inverters is a bit "dirty" so
I don't want to do it if it will harm my GD-1B.

Ken KG0WX

In article . com,
kg0wx wrote:

Can a Heath GD-1B be safely powered from a DC/AC power
inverter? I know the output of most inverters is a bit "dirty" so
I don't want to do it if it will harm my GD-1B.

I rather doubt that doing so would cause damage, as the power supply
is transformer-coupled.

I'd be more concerned about incorrect or flaky operation. The GD-1B
doesn't appear to have particularly good RF/EMI filtering on its AC
supply... there's just a single-stage R/C on the high-voltage DC and
none on the filament. A stepped-square-wave inverter would probably
end up dumping a lot of HF hash into the circuit. This might cause
the oscillator/detector to misbehave in any number of ways - the meter
might jump around a lot as you tune, or the oscillator frequency might
"pull" to the frequency of one of the inverter harmonics anytime you
got near it, etc.

You might be able to improve matters by installing a hefty,
high-attenuation RFI/EMI filter (such as the sealed-in-metal modules
sold by Corcom and others) in between the inverter and the GD-1B.
Adding some EMI filter components inside the GD-1B might also help...
ferrite beads on the mains wires, some .01 uF - .1 uF mains-rated
filter capacitors across the primary and secondary transformer
windings, etc.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Thanks, Dave! Lot's of great info. I just bought a mint GD-1B in the
original box with 7 inserts. I understand what freq range the 1st 5
inserts do as they are marked and there is a picture in the manual.
Problem is the last two inserts - they have a lot of wire (looks like
AM antenna micro wire). One has 1 coil of wire, the other 2 coils.

Unlike the regular coils, these are wound inside the plastic form
and sealed. Any idea what they are for? Is that the 341-A coil set?
How do I use them (what range)?

Thanks again....

Ken KG0WX

In article .com,
kg0wx wrote:

Thanks, Dave! Lot's of great info. I just bought a mint GD-1B in the
original box with 7 inserts.

That sounds like a really nice find! I'd be very interested to learn
how you find its sensitivity. There seems to be a big range in dipper
output and sensitivity, with most of the modern transistorized units
coming up looking rather wimpy compared to classic firebottle types
such as the Measurements 59.

I understand what freq range the 1st 5
inserts do as they are marked and there is a picture in the manual.
Problem is the last two inserts - they have a lot of wire (looks like
AM antenna micro wire). One has 1 coil of wire, the other 2 coils.

Unlike the regular coils, these are wound inside the plastic form
and sealed. Any idea what they are for? Is that the 341-A coil set?
How do I use them (what range)?

That's probably the additional coil set mentioned in the manual (which
you can download from http://bama.sbc.edu or its less-heavily-loaded
mirror site at http://bama.edebris.com/

The standard set of 5 coils goes down to 2 MHz. The manual says that
the extra coils extend the frequency range to 350 kHz, but doesn't say
how many coils are included in the extended range. Since it appears
that each of the coils in the standard set covers a frequency range of
about 2.5:1, I'd guess that one of your extended coils covers from
somewhere around 800 kHz up to 2 MHz, and the other covers from 350
kHz to 800 kHz. The one with more wire, is probably the latter. You'd
use these coils in just the same way that you use the other five.

If you have access to a reasonably sensitive RF frequency counter it
shouldn't be difficult to confirm this. I use an MFJ 269's freq-counter
function, with a few inches of wire soldered to a BNC connector, in
order to do fine calibration of the output of my Measurements 59 grid
dipper. Just plug in the coil, turn on the dipper, hold it near the
frequency-meter wire probe, and the probe will probably pick up enough
RF to give a good indication.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Thanks for the link. BTW, not only was this dipper new in the box,
the 2 lower coils were still wrapped in parchment in another box.

Price? $25

I swept the dipper from 350kc to 260mc, listening on everything
from my K2 to a scanner to my 2m/440 mobile - this thing has got
a very stout output!

73's de Ken KG0WX

In article . com,
kg0wx wrote:

Thanks for the link. BTW, not only was this dipper new in the box,
the 2 lower coils were still wrapped in parchment in another box.

Price? $25

Did you really want to spend ten lifetimes' worth of good-karma points
all at once? :-)

I swept the dipper from 350kc to 260mc, listening on everything
from my K2 to a scanner to my 2m/440 mobile - this thing has got
a very stout output!

Excellent. In my experience, as a general rule, the dippers having
higher output can achieve a usable dip with looser coupling to the
circuit being measured... which means less pulling of the oscillator,
less parasitic loading, and a more accurate measurement overall.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!