Adaptation for 2200m Rx/Tx

Discussion in 'The Low Bands - 630/2200 Meters - VLF' started by WQ2H, Nov 18, 2018.

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  1. WQ2H

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


    Moved over from:

    First, note typo
    - existing antenna is 160m four wave, not full wave. And thanks to all for all the comments !

    Plan update 18 NOV 2018:

    Transceiver: Motion sensors TVTR2 driven by a Flex 6600M (Motion Sensors suggests that 50W into the loading coil should yield <1W EIRP depending largely on the efficiency of the antenna) The TVTR2 has a Tx inhibitor should carrier frequencies outside the 135.7 - 137.8 kHz band be detected - but I will probably build the 136 kHz pass filter in Dennison's book anyway as it is fairly simple.

    Measurement: WaveNode WN-2 with L/M-1 sensor (100 kHz-5 mHz) on output of transverter. This will augment the graphical SWR meter on the TVTR2.

    Antenna (the long pole in the tent): "Re-purposed" existing 160m 4-wave loop by breaking the feed point at the house, moving one end to a safe distance from the house (~40' to avoid corona), and repositioning the feed point about 30' from the house also.

    Following Dennison's excellent book,(highly recommended) I will also add a 30' vertical segment - essentially making it a 30' vertical with a 2100' hat. The base of the vertical section will be the feed point and will contain a 3 loading coil set (1 variometer, 1 full coil, and 1 multi-tapped full coil) as well as a impedance match box between the coils and the radio. The variometer will have +/- 300uH adjustment in both directions and I will also have several spare discreet 100uH coils available for extra balancing if needed. I will house everything in a weather-proof plastic enclosure at the base of the vertical section. There will be about 40' of coax, and a few surge protectors, between the match box and the radio. I will also need to re-enforce the wire insulator system for spatial isolation at each of the 17 wire "hang points".

    The ground connection is still TBD. I have a very good existing ground farm about 30' back toward the house, or I could build a new ground right at the feed point. I prefer to have it on the existing ground, but we'll see how that plays out.

    N1BUG & K3MF were my first WSPR Rx points on 137 kHz, so I think this antenna with the proper modifications may have a fighting chance.

    Very close to finishing the variometer & coils - so I'll post a photograph when complete. :)
    Jim, WQ2H
    KD6RF likes this.
  2. K6CLS

    K6CLS Ham Member QRZ Page

    Yes please!

    You have the right book and great folks helping.

    I haven't set up a TX antenna for the band. But I think for RX my Pixel magloop did very well. Nice to be able to eliminate e plane noise, and steer it away from other noise sources.

    Wishing you every success on the air. And don't set fire to anything!
  3. WQ2H

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

    Roger on the fire ! (6" of snow on the ground here - but a fire is still a fire)

    I've worked in a HV lab on one of my first jobs out of college so I have an idea of what to look for.

    I'm probably the only ham I know buying corona balls for the screws.......! :eek:

    Jim, WQ2H

  4. WB5WPA

    WB5WPA Ham Member QRZ Page

    I don't recall seeing your operation/station working into Europe on 160 ... did you ever have success on that band using that 160 antenna?
  5. WQ2H

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

    No, not really. The big loop does not seem to work as well as the 8-band Buckmasters on 160 - I have two positioned perpendicular with the long ends W and S.

    The big loop works great within New England, and performs well on 75m also, but it was from day one an experiment. I have a separate smaller 1-wave 80m loop also that I use for phone/digital (mostly Rx).

    This is why I'd like to remove the 1:1 current balun and re-purpose the big one for VLF. It's the only antenna that seems to be able to Rx 2200m (within 350 miles) repeatedly at the moment. I know a "30' vertical with a 2100' hat" sounds goofy, but from what I've heard from other folks it may work fairly well. It's a work in progress.
  6. WB5WPA

    WB5WPA Ham Member QRZ Page

    You know, propagation on 160 has really picked up since you last tried it around 11/09 or so (I pulled up the 'spot' records with your callsign). We here in Texas weren't getting many EU spots until the last few weeks even.
  7. WQ2H

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

    Yes - I have been following your spots. I've been focusing on gathering 2200m data with the couple of stations that I can hear regularly (JT9/FT8). Maybe I will set it up again on 160.

    The variometer is really the big project - found a really nice coffin size waterproof enclosure at Lowes while Christmas shopping. My wife thinks I am nuts of course. Although it is a "nice green color" that will blend in well out in the woods. :rolleyes:

  8. WQ2H

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

    Just put up a block diagram of my "in-process" 2200m set-up on my QRZ page.

    The variometer is just about finished - working out the best wiring scheme, and positioning of the bulk-head connectors. After that, a few mods to the antenna, and finish up the API sensor routine, and it should be ready to go on the air.

    Here's a photo of the variometer assembly - in a weather proof container so it can easily be positioned at the base of the vertical section.

    Jim, WQ2H

  9. WB5WPA

    WB5WPA Ham Member QRZ Page

    I've been eyeing different kinds of surplus fixed-value capacitors on the website. Going to use, I think, a series-parallel combo of caps to make the big vert loop resonant on 2200 meters ... unlike you "vert E-probe probe" guys us loop guys have to capacitively "load" our loops to make them resonant! Whereas I need right about 2000 pF at 475 kHz I'll need about 24,000 pF to make the loop resonant at 137 kHz.
  10. WQ2H

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

    After not getting it quite where I want it - decided to rebuild the match auto-transformer to try and get a better resolution. The version in Dennision's book had 32 taps, which correlates to about 40 ohms per tap in my specific "area of interest". I can get twice the resolution with taps on every turn, so I'll give that a try.

    For anyone interested - this is another excellent reference on VLF/LF receiving loops:

    Jim, WQ2H

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