easy and sucsessful op on LF

Discussion in 'The Low Bands - 630/2200 Meters - VLF' started by WA1MTZ, Aug 12, 2019.

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  1. WA1MTZ

    WA1MTZ Ham Member QRZ Page

    no need to reinvent the wheel, I use a arc-5 rx on 630m, a bc779 on 185 kc and an ATR-13 xmtr with a bc-603 ant tuner. use an rf ammeter! ur ant Z will be abt 2 ohms! If you can find a Nautel
    beacon tx you will have something real nice! has built in audio compression too, solid state PDM
  2. K9STH

    K9STH Ham Member QRZ Page


    I am not familiar with that unit. However, the Collins ART-13 with the LF module will work on the 630-meter band.

    Glen, K9STH
  3. WA1MTZ

    WA1MTZ Ham Member QRZ Page

    wow, it should have been labeled ART-13! sri abt that! also, I hope that any newcomers be advised that you need a VERTICAL ant to tx on LF, horizontal, and beverage types are good for rx only. Some of the best antennas are the cage type vertical s 4 wires spaced 10' apart on a wood mast about 30' high, bottom about 8' off the gnd ,all 4 wires connected together, another good antenna is the 'T' top has 2 wires spaced 8' 80-100' long with 2 wires coming down from the centre to ground level and a loading coil-no capacitors used, just inductance. coil should be litz cable or #8 wire, remember the Z is so low that the loss in the coil can be high. a book written in the 1950's by ITT, is avail free download at https://archive.org 500 page communications manual, look under LF antennas. ps, most air beacon stations ran 25-50w with loaded vert 35'
    W1TRY likes this.
  4. K9STH

    K9STH Ham Member QRZ Page


    I figured that it was really an ART-13. I have never owned one but have seen a few of the transmitters.

    For receiving, on the 630-meter band, I can choose from a BC-453, BC-348, TS-440SAT, or a receiving converter into my Heath SB-301. Receiving below 210 kHz I use a Rycom 6010. It is an AM / SSB "selective voltmeter" which is actually a VLF receiver. The Rycom has a digital readout and is very sensitive.

    True ground wave propagation is present on the 2-lowest frequency bands and a vertical is absolutely necessary for true ground wave.

    Glen, K9STH
  5. KB7NRN

    KB7NRN Ham Member QRZ Page

    Isn't 630 mtrs considered Medium Frequency? And don't you have go below 300 kHz for Low Frequency and isn't anything below 30 kHz considered Very Low Frequency?
  6. K9STH

    K9STH Ham Member QRZ Page


    Yes, between 30 kHz and 300 kHz is, by definition, LF and below 30 kHz is VLF.

    The Rycom 6010 goes all the way down to below 1 kHz. As such, it is a true VLF receiver.

    Glen, K9STH
    W0BTU likes this.
  7. WQ2H

    WQ2H QRZ Lifetime Member #214 Platinum Subscriber Life Member QRZ Page

    The ART-13 was (is) a work of art. You could definitely work 630m with one of the newer LF modules - earlier modules were only 200-400 kHz.

    I wouldn't say MF/LF is "easy" - but it is a lot of fun. Fortunate here to have made QSO's on both - but it's tough going. MF not so bad but - LF takes patience.

    Reference on antennas - you definitely need verticals:

    For 475 I use a 35' vertical with a 100' 3-conductor hat and four 100' radials on the ground - load coil is about 100 uH. With 100W TOP I get about 1W EIRP.

    For 137 I use a 40' vertical with a single 550' hat (a repurposed 160m full wave loop) and a small ground farm consisting of about six 6' rods in the ground on a 8' perimeter from the base - load coil is 3000 +/- 150 uH. With 400W TOP I get about 250mW EIRP.

    VLF is a whole different animal - but I did spring for Dennision's book and I'm reading up on it. Good luck !

    Jim, WQ2H / WK2XAH
    W0BTU and K6CLS like this.

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