[time-nuts] 60 KHz Receiver

Bob Camp lists at rtty.us
Tue Oct 5 17:52:31 EDT 2010


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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