[time-nuts] 60 KHz Receiver

[Bob Camp]

Hi

Same gotcha as the horizontal dipole - most of the energy is shorted out by the ground. Think of a transformer with a shorted turn.

Bob


On Oct 5, 2010, at 5:58 PM, J. Forster wrote:

> A loop around the house?
> 
> -John
> 
> ==============
> 
> 
>> Hi
>> 
>> Ok, the next layer to this onion is the antenna. At 100KC your antenna is
>> 35X smaller than it is on 80 meters foot for foot. In other words, your
>> 100' tall vertical on 80 equates to a <3 foot tall antenna at 100 KC. QRP
>> on 80 with a 3' transmit antenna anybody? Been there done that, not much
>> range at all. At VLF forget about transmitting with a horizontal antenna
>> unless you are airborne.
>> 
>> It's not just the antenna, the ground counts as well. If you are by the
>> seashore that may not be a big deal. If you are inland, prepare to lay
>> many very long radials.
>> 
>> ----------
>> 
>> After that you hit signal to noise. The receivers worked as well as they
>> did because they had an enormous signal to work with. There's an amazing
>> amount of crud running around down below 200 KHz these days. Even for
>> timing you need a lot of signal to get good results.
>> 
>> Bob
>> KB8TQ
>> 
>> Ham for way more than 30 years....
>> 
>> 
>> On Oct 5, 2010, at 4:59 PM, paul swed wrote:
>> 
>>> Well crazy as it sounds if you are at 100 KC you might just want 1 loran
>>> tower in a chain or even fewer. You only need 1 station not 3. Timing
>>> rcvrs
>>> worked on one signal.
>>> 
>>> 
>>> On Tue, Oct 5, 2010 at 4:46 PM, <shalimr9 at gmail.com> wrote:
>>> 
>>>> Not necessarily, on 3 phase systems, you would have to be creative to
>>>> get
>>>> below .9
>>>> 
>>>> You can easily get to .95 with a simple multipulse rectification.
>>>> Beyond
>>>> that, other than regulatory compliance, you do not gain much
>>>> efficiency.
>>>> 
>>>> I can't imagine these systems running on anything other than 3 phase
>>>> power.
>>>> 
>>>> Didier
>>>> 
>>>> Sent from my Verizon Wireless BlackBerry
>>>> 
>>>> -----Original Message-----
>>>> From: "J. Forster" <jfor at quik.com>
>>>> Sender: time-nuts-bounces at febo.com
>>>> Date: Tue, 5 Oct 2010 13:37:21
>>>> To: Discussion of precise time and frequency measurement<
>>>> time-nuts at febo.com>
>>>> Reply-To: jfor at quik.com, Discussion of precise time and frequency
>>>> measurement
>>>>      <time-nuts at febo.com>
>>>> Subject: Re: [time-nuts] 60 KHz Receiver
>>>> 
>>>> And the Power Factor sucks, so there is a lot less real power being
>>>> used.
>>>> 
>>>> -John
>>>> 
>>>> =============
>>>> 
>>>>> Ok, but that is no megawatt!
>>>>> 
>>>>> Also, most of the transmitters were doing multi duty, handling
>>>>> several chains simultaneously.  That would up the average power
>>>>> proportionately.
>>>>> 
>>>>> -Chuck Harris
>>>>> 
>>>>> Poul-Henning Kamp wrote:
>>>>>> In message<4CAB888B.4040604 at erols.com>, Chuck Harris writes:
>>>>>>> It is a pulse transmitter.  It makes short bursts of 10 or 12
>>>>>>> pulses,
>>>>>>> and then waits one GRI, and then does it again.  I would think the
>>>>>>> actual continuous power draw is around 10Kw.
>>>>>> 
>>>>>> http://phk.freebsd.dk/photos/L9007M/dscf0458.jpg.html
>>>>>> 
>>>>>> About 50kW for Ei�i (400kW, 9007M)
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
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>>>>> 
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>>>>> 
>>>> 
>>>> 
>>>> 
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> 
> 
> 
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