My thoughts on MF and LF.

Discussion in 'The Low Bands - 630/2200 Meters - VLF' started by WA4ILH, Nov 9, 2017.

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  1. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    What you really need to look at is the D-layer absorption difference between the bottom and top ends. Most of the really good AM DXing is at the top end. Of course there are always exceptions. :)
     
  2. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    The ground conductivity maps that the FCC uses for broadcasters were developed in the 1950s and haven't been really revised since then. It's time to do them all over again!
     
  3. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    You'll notice, it doesn't even include Alaska. We're about 4 more decimal places to the right of the worst continental ground conductivity. :(
     

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  4. W0AAT

    W0AAT XML Subscriber QRZ Page

    I am on the northern edge of that 30 in MN... where it drops to 8 is the MN river valley 8 miles north of me... When I dig a hole here I have a foot of turf roots, 2-3 more feet of black dirt then a layer of hard pan clay 6" to 12" thick then it turns to gravel
     
  5. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    What's really surprising is that the best ground conductivity is NOT right on the coastal areas. Always been a mystery to me.
     
  6. KA0HCP

    KA0HCP XML Subscriber QRZ Page

  7. N3DT

    N3DT Ham Member QRZ Page

    AAT, could you send me about 5 - 20 ton trucks of that black loam you can dig up to me here in VA, I have a yard full of clay and granite that can use it. It might help my ground conductivity.
     
  8. K9STH

    K9STH Ham Member QRZ Page

    DT:

    Move to Richardson, Texas! We have the best ground conductivity in the entire 50-states. At one time, there were no less than 3-each antenna test ranges within 4-miles of my house because of the ground conductivity.

    One straight west of my house, less than 2-miles; one straight east of my house about 4-miles; and one southeast of my house about 2-miles. All of those ranges are now gone, the land having been developed for either commercial uses or large residential development.

    Glen, K9STH
     
  9. N3DT

    N3DT Ham Member QRZ Page

    I've been to TX and actually my wife got her PHD at Austin. But there's no way I'd move to TX. My uncle was an oil man for SunRay and my family is from KS, but my family left there in the 50's and I have no inclination to move back. Sorry.

    If I went to the Midwest I'd go to Minneapolis. They've still got deep loam there. And lots of snow. Keeps the rif-raf out.
     
  10. W0AAT

    W0AAT XML Subscriber QRZ Page

    Comes with living on what used to be virgin prairie!
     
  11. KE4GQE

    KE4GQE Ham Member QRZ Page

    I'm interested in finding a both affordable hot receiver for mostly LW broadcasts. Over the years I've been watching the HP-3586B Selective Level Meter but apparently those guys selling on ebay want to retire off of those surplus sales. Same problem on the ADF Receivers Any Ideas?
     
  12. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    Building good VLF receivers is quite easy. It's the rarity of the off-the-shelf ones that sets their unrealistic prices.
     
    W0BTU likes this.
  13. K9STH

    K9STH Ham Member QRZ Page

    Look for selective voltmeters. Those are actually VLF receivers and, usually, go from DC to 200 kHz or higher. My Rycom 6010 covers up to around 215 kHz, has AM, LSB, and USB capabilities, and a digital frequency readout. Such are, generally, considerably less expensive than units sold as "receivers" and have calibrated analog meters as well.

    Glen, K9STH
     
  14. N8AFT

    N8AFT Ham Member QRZ Page

    Good old Drake SPR-4 is vy hard to beat for the money spent... Seems the Rycom is vy limited at only DC to 200khz.
    It won't go up high where the hams are above 400khz?
     
  15. K9STH

    K9STH Ham Member QRZ Page

    AFT:

    There are all sorts of receivers that cover the 630-meter band that do a very good job including the old surplus BC-453 and the BC-348 series as well as a fair number of "modern" transceivers like the TS-440S series. It is the 2200-meter band that is difficult for many to obtain receivers although there are a number of inexpensive receiving converters that do a pretty good job.

    For the 630-meter band I have both a BC-453 and a BC-348 as well as a TS-440SAT plus a converter that covers both the 630-meter and 2200-meter bands as well as the Rycom. It is the transmitting side that is taking a while to get going!

    Glen, K9STH
     

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