We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

Author Topic: SWL Antenna question....  (Read 1698 times)

Offline East Troy Don

  • DX Legend
  • ******
  • Posts: 1371
  • "If you can't convince them, confuse them" Truman
    • View Profile
SWL Antenna question....
« on: August 21, 2018, 0114 UTC »
I currently run my Grundig 750 with an Alpha Delta SWL Sloper positioned from approximately   90 degrees to 270 degrees.  I recently purchased a FRG-7700 and would like to run the Yaesu  thru a secondary antenna positioned 90 degrees perpendicular to the Sloper (0 to 180 degrees).  I have 2 questions:  Can I run both antennas off the same 25 foot mast and (2) will I run the risk of signal cancellation due to the proximity of the radiating elements?
Ok, maybe a third question....would I be better off using a vertical for the FRG at the top of the mast?
I appreciate any help on this, everyone.
Thanks,
Don
Primary: Yaesu FRG-7700  Secondary: ICOM R75 Tertiary: Grundig  750. Tecsun PL-990X, Tecsun PL-880 . Malahit DSP SDR V3,  Alpha Delta  SWL Sloper antenna. : Also, 1940 Mantola am/sw tube. CountyComm GP-5/SSB hand held, Tecsun PL-380 ,et al.  QTH: EAST TROY WI  USA.  Sea Level: + 320 meters .  75 miles (but not far enough) NNW of Chicago

Offline Josh

  • DXing Phenomena
  • *******
  • Posts: 4322
    • View Profile
Re: SWL Antenna question....
« Reply #1 on: August 21, 2018, 1859 UTC »
Try them all, add a vertical to the mast as well as the other sloper or whatever it is you intend to add. I'd also have some antenna switching capabilities too. By shunt feeding you can extract rf from the mast itself.

http://www.qsl.net/w9rb/webdoc9.htm


http://www.vias.org/radioanteng/radio_antenna_engineering_02_03_04.html


As to signal cancellation, the conditions would have to be ideal, meaning you will likely never find them. Something to consider however is the fact that antennas typically reradiate 2/3 of the received signal, only 1/3 of the received energy gets down the line to your rx. If you have more antennas nearby, their reradiations may increase overall rf extraction. This is why yagi and other beams work.
« Last Edit: August 21, 2018, 1903 UTC by Josh »
We do not encourage any radio operations contrary to regulations.

Offline pinto vortando

  • Hero Member
  • *****
  • Posts: 924
    • View Profile
Re: SWL Antenna question....
« Reply #2 on: August 21, 2018, 2201 UTC »
Try them all, add a vertical to the mast as well as the other sloper or whatever it is you intend to add. I'd also have some antenna switching capabilities too.

x2

Be sure to provide proper lightning protection and grounding. 
Das Radiobunker somewhere in Michigan

Offline East Troy Don

  • DX Legend
  • ******
  • Posts: 1371
  • "If you can't convince them, confuse them" Truman
    • View Profile
Re: SWL Antenna question....
« Reply #3 on: August 22, 2018, 0139 UTC »
Very helpful stuff, guys -  Mucho appreciado!

Don
Primary: Yaesu FRG-7700  Secondary: ICOM R75 Tertiary: Grundig  750. Tecsun PL-990X, Tecsun PL-880 . Malahit DSP SDR V3,  Alpha Delta  SWL Sloper antenna. : Also, 1940 Mantola am/sw tube. CountyComm GP-5/SSB hand held, Tecsun PL-380 ,et al.  QTH: EAST TROY WI  USA.  Sea Level: + 320 meters .  75 miles (but not far enough) NNW of Chicago

 

HFUnderground T-Shirt
HFUnderground T-Shirt
by MitchellTimeDesigns