1 / 11

Field Day Antennas, June 2018

Field Day Antennas, June 2018. 40m Phone. 15m Dual. 20m Phone. 40m Digital. 20m CW. 20m Digital. 80m Phone. 80m CW. 40m CW. 10m Dual. Field Day Antenna Tuners, June 2018.

naomistewart
Télécharger la présentation

Field Day Antennas, June 2018

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Field Day Antennas, June 2018 40m Phone 15m Dual 20m Phone 40m Digital 20m CW 20m Digital 80m Phone 80m CW 40m CW 10m Dual

  2. Field Day Antenna Tuners, June 2018 Since all loop antennas were to be fed with 450 ohm ladder line, it was determined that each antenna should have it’s own antenna tuner and it’s own bandpass filter. However, the club owned only one 160 meter and one 10 meter bandpass filter. For 80m, 40m, 20m and 15m we had two for each band. The shortage is because all filters were purchased prior to the need for separate digital stations. As a result, at the direction of the President, a single 40m bandpass filter was purchased and added to the club’s collection. This still left us short one 20m bandpass filter. We therefore opted to use the beam antenna for 20m CW as it was further from the other antennas and would need the filter the least.

  3. Commercial Tuner Designs The balanced tuners above can be subject to core saturation at high SWR resulting in tuner failure!

  4. Link Coupled Tuner Designs

  5. Fairly Good is Not Great! So that was what we got for results at Field Day 2018, fairly good. On some rigs the SWR went down to 1:1, on others 1.5:1 was closer to the best we could do. On other antennas it was 2:1. And without being able to relocate the taps, we could not get all rigs down to 1:1 or operation.

  6. The Fix is Never Easy Now if we could just add a rotary switch to each tuner, and allow it to select the various taps, our problem would be solved. Because our secondary windings are inside our primary windings the coils would have to be completely rebuilt to accomplish this. So it may be time to redesign the Field Day tuners.

  7. Z-Match Tuner Designs

  8. Z-Match Tuner Designs According do DJ0IP, the advantages of the Z-Match are…. Relatively simple circuit Low Cost components Ease of tuning And the disadvantages are…. Efficiency goes up with higher SWR’s High SWR can mean high voltages, requiring feed line length modifications, or higher voltage rated capacitors The is no commercial source for this design.

  9. Other Choices Balanced L-Network – requires a pair of matched synchronized roller inductors. Very expensive. Balanced T-Network – each tuner requires two sets of identical capacitors ganged together. Also somwwhat expensive. Can be misadjusted for high loss. (MFJ-974B) Balanced Pi-Network – again requires a pair of matched synchronized roller inductors. Very expensive. Link Coupling – will require rotary switch and new coils S-Match – new design, uses two torriodal cores but has interesting possibilities

  10. The S-Match

More Related