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I need a transmitter built for a receiver from 42-144 kz. Lower end preferable. I have a function generator that I am told will supply the correct frequency (50 khz )+-) and it needs to be powered by 1 watt, sine wave, antenna will be 16 guage wire laid in a 12mx12m square on the ground. I have an EMFAD 12/4 wich was designed to receive the long range transmissions to the submarines by the navy, but many or all have shut down and I am unable to receive a suitable signal. Their new PRO model has the option of buying a seperate transmitter just incase their other three frequencies are not present wherever you are. Am hoping we can build one and it will prove to be the answer for this instrument.
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? You need a Loran-faked signal ? Why ?Originally posted by Black Cloud View Post
Some Loran TX are still alive....
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Can you use the 77 kHz time signal ?
Somebody told me that it is in use as a transmitter / receiver detector.
Large iron ( ...gold
...) make some chance in the 77Khz receive signal ?
Can also be used for cave finding ?
Thats al I know....
Best regards.
ApComment
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Thanks for the link, Ivconic, but all that is over my head. That's why I am asking someone else to build it for me. We talked about this EMFAD long ago, and I think with the correct tx it will function properly. Thanx, MBOriginally posted by ivconic View PostComment
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I need a signal in the 50mkz range, for my receiver that receives 50khz. If those Lorans are still out there, I sure cannot receive them.Originally posted by Max View Post? You need a Loran-faked signal ? Why ?
Some Loran TX are still alive....Comment
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Max, there is supposed to be an active one in El Paso, and also Raymondville, TX. but I searched all over those areas and could not receive it. I'm sure somewhere there is an suitable signal but I cannot just go all over north america looking for it. That is why I wish to build a tx , then where ever I am I will take the signal with me.Originally posted by Max View Post? You need a Loran-faked signal ? Why ?
Some Loran TX are still alive....Comment
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Really ?Originally posted by ApBerg View PostCan you use the 77 kHz time signal ?
Somebody told me that it is in use as a transmitter / receiver detector.
Large iron ( ...gold...) make some chance in the 77Khz receive signal ?
Can also be used for cave finding ?
Thats al I know....
Best regards.
Ap
And who told you that ?
You mean using DCF77 from Mainflingen , right ?
Actually runs on 77.500KHz not 77...
Kind regards,
MaxComment
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Hmmmm...Originally posted by Black Cloud View Post
I see... some are far...some are just active sometimes... others don't work if not for digital TX...
Why don't you try to tune to 60Khz of WWWB station of NIST, Fort Collins - Colorado... ?
It covers all north america... about 2000miles diameter... effective radiated power is over 70KW!
Kind regards,
MaxComment
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Looking at this link:
http://www.geotech1.com/forums/showthread.php?t=11431&highlight=ug12
ha,ha,ha,ha....how enthusiastic was i at the time!??!?
My final experiences with UG 12/24 are very bad. I would not waste my time on that any more.
But....might be i am wrong. Do not listen me each time i say something.
Regards!
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Well, I am in range of 2000 miles for sure. Would this 60 khz come through the ground as well as the air? My instrument does not display the actual frequency, just the setting on a dial. Is there a simple frequency counter I could get and see if that one is present in my area? I'm not very knowlegable along these lines, that's why I'm asking for help. Would it be possible that all these other frequencies floating around are causing it problems, i.e. All the TV analog signals will be gone after today, would they have affected this range? Thanks for your help.Originally posted by Max View PostHmmmm...
I see... some are far...some are just active sometimes... others don't work if not for digital TX...
Why don't you try to tune to 60Khz of WWWB station of NIST, Fort Collins - Colorado... ?
It covers all north america... about 2000miles diameter... effective radiated power is over 70KW!
Kind regards,
MaxComment
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Hi,Originally posted by Black Cloud View Post
I don't know about your instrument... what is I mean... simple receiver ?
Anyway, if you have an LF receiver and can tune down to 60Khz you'll receive WWWB signal, at least in part of the day.
Part of signal is carried by ground-waves... so you can receive strong under certain conditions... e.g. far from buildings and when there's not so hi-ionosphere activity... (cause ionosphere traveling/reflected waves causes interferences mostly in that scenario).
At sunset and after , usually, the reception of ground-waves is stronger... much depends also on place where you are... and if there are/aren't big sources of noise in the band of interest around 60Khz.
Using just a frequency counter is not enough...to see if the signal is there or not...
To know if signal you can receive or not... just buy some cheap radio-controlled-watch stuff... (of course , for WWWB signal, some can use different ones automatically) and see if the watch adj by itself to the actual time... if so... you receive the signal.
Another test could be using a scanner receiver that covers LF band... then mount a simple loop-antenna for VLF reception... no need of preamp in most cases... then tune to 60Khz and look for the signal.
Kind regards,
MaxComment
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OK, I'm getting an online education here. I will wait until late evening and see what happens out there. There are no other transmitting devices around that I know about, so maybe I will pick up something. This instrument is an EMFAD 12/4, and it receives a VLF frequency in the range of 44 khz to 142 khz. The lower numbers give more depth and less resolution to the imagery and the higher the frequency the closer objects have better resolution. I am more interested at this time in finding a particular void (cave) so I would like to have a good strong signal around 50 or so. Maybe I can find something this evening. I will use a GPS and set the clock wrong and see if it resets itself. Thanks, MikeOriginally posted by Max View PostComment
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http://en.wikipedia.org/wiki/DCF77 This article give the range of 2000KM from Frankfurt, Germany, and it didn't say anything about one over here. I will look towards Ft. Collins tonight. The new PRO model uses the 77 as one of its choices of frequency. The instrument was manufactured about 70 mile from Frankfurt. Now I know why they work so well over in Europe.Originally posted by Max View PostComment
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Hi,Originally posted by Black Cloud View Post
yes, the signal from Mainflingen is strong in all Europe... maybe less just at extremes latitudes ...like northern and southern places... don't know. The central europe is totally well covered by DCF77 , and so clocks and other stuff related works about good.
Now... I don't know about EMFAD device but if works in europe at that frequency you cannot obtain same results on 77500Hz there in the north america, so must look for Fort Collins 60Khz signal (indeed it's really strong signal so probably you'll receive it)... just you have to experiment using some LF receiver... I think, even a small dirty-cheap chinese made clock... tuned on WWWB frequency.
A thing to keep in mind is that in the clocks there are very selective filters for clearing out interferences... so if you see the clock receive the signal it's also cause of that: that's expecially true for urban areas with lot of electrical noise around and inside e.g. reinforced concrete buildings... where LF signals (if) arrive are very attenuated.
In open space... e.g. farm land the things are easy about it, though the coverage is not equal in any place... cause there are e.g. mountains that could create an obstacle to the ground transmission of the RF wave, but generally open space, far from power lines is the best scenario to receive that kind of signals.
Hope will hear good news from you.
PS: don't use gps for the test... gps takes clock signal from satellites... not from WWWB station on 60Khz... you need a cheap radio controlled clock...
Kind regards,
MaxComment
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