Search found 4 matches

by jmcc
Wed Dec 26, 2018 12:44 pm
Forum: Antennas
Topic: DIY QFH Antenna troubleshooting
Replies: 13
Views: 43236

Re: DIY QFH Antenna troubleshooting

The balun might be an issue as it looks like the copper used is raw and not enamelled copper wire. This means that the coil could theoretically be shorting out if any of the turns are touching.
by jmcc
Tue Feb 07, 2017 4:05 pm
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 9249

Re: Guidelines for choosing coaxcable for use >1000 MHz

I would not call/consider any coax that has the diameter of the 50 Ohm RG-174 type coax a good quality thin cable for use at 1 GHz. Thin cable is often used in short lengths for patch cables with test equipment and some pigtails where a device with a small connector has to be interfaced to a larger...
by jmcc
Sat Feb 04, 2017 1:50 pm
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 9249

Re: L-Band receive antenna

With difference in cable loss I was pointing to the difference in cable loss between cable used at at the ½ wave cable design and the ones attached to the magnetic mounts, which for cost reasons will not use any of the available “low” loss thin cable. Any cheap double shielded cable for distributio...
by jmcc
Mon Jan 30, 2017 1:17 am
Forum: Antennas
Topic: Planar Disk Antennas...
Replies: 2
Views: 5973

Re: Planar Disk Antennas...

I am not sure how the size of the gap relates to the upper frequency though...... The size of the mesh gap, from memory (working with satellite TV antenna design years ago) is related to the wavelength and has to be less than a quarter wavelength (sometimes a tenth) of the highest frequency in use....