Search found 37 matches

by HighSNR
Tue Jun 18, 2019 2:40 am
Forum: Antennas
Topic: Strangest thing with my antenna!
Replies: 4
Views: 1241

Re: Strangest thing with my antenna!

That sounds like the most likely scenario. As admin says, the yagi is unidirectional, but it is also tuned to the TV frequencies and may not perform well outside this band. Additionally the amplifier may also contain a filter to reject out of band signals. Some amplifiers have a second input for an ...
by HighSNR
Mon Jun 10, 2019 4:34 am
Forum: Antennas
Topic: Holiday antenna
Replies: 10
Views: 993

Re: Holiday antenna

I use that: https://www.tindie.com/products/hagster/ultra-wideband-vivaldi-antenna-800mhz-to-6ghz/ The problem is the are a little bit brittle. The actual antenna is fairly strong and I have yet to break one, but it is possible to damage the connector, especially if attaching heavy coax. If you hav...
by HighSNR
Sun Jun 09, 2019 5:37 pm
Forum: Antennas
Topic: Holiday antenna
Replies: 10
Views: 993

Re: Holiday antenna

I can recomend my spiral antennas for covering 300MHz upward. They also seem to work fairly well from 90 to 200Mhz, but no use at all at HF.

https://www.tindie.com/products/15447/
by HighSNR
Sun Jun 09, 2019 9:58 am
Forum: Antennas
Topic: Holiday antenna
Replies: 10
Views: 993

Re: Holiday antenna

I have never heard of anyone getting arrested in Europe for scanning. Rules are probably different for different countries in the EU, but so long as you are not demodulating and intercepting comms where people would have an expectation of privacy, you are probably ok. The old classic was listening t...
by HighSNR
Fri Apr 26, 2019 7:50 pm
Forum: Antennas
Topic: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...
Replies: 6
Views: 1214

Re: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...

The impedance should be approximately real as the length has been tuned to make it resonant(XC = XL). If possible it is always better to tune an antenna this way rather than rely on a matching network of L's and C's to shit it round the smith chart. Sometimes (particularly with small antenna) this i...
by HighSNR
Sun Apr 14, 2019 2:13 pm
Forum: Antennas
Topic: Another Double Cross Antenna build (went wrong)
Replies: 16
Views: 2488

Re: Another Double Cross Antenna build (went wrong)

Its rare for a satellite to actually be directly overhead. Most commonly they will acutally be at a lower elevation. The Lindenblad (double cross) is designed to give circular polarisation as a replacement for a linear dipole. For coverage at 90degree elevation you can use a turnstyle(crossed dipole...
by HighSNR
Sun Apr 14, 2019 1:33 pm
Forum: Antennas
Topic: Another Double Cross Antenna build (went wrong)
Replies: 16
Views: 2488

Re: Another Double Cross Antenna build (went wrong)

I would expect this antenna to have a null directly above and below.

https://www.amsat.org/articles/w6shp/lindy.html
by HighSNR
Sat Apr 13, 2019 7:53 am
Forum: Antennas
Topic: What antenna is this
Replies: 1
Views: 511

Re: What antenna is this

We can't see the actual antenna, but it's probably an L-Band circular patch antenna. The 'directional coupler on the back is actually a 90 degree hybrid used to feed the antenna and provide the circular polarisation.
by HighSNR
Thu Apr 11, 2019 5:45 am
Forum: Other SDR Devices
Topic: List of HF SDR Transceivers
Replies: 5
Views: 1009

Re: List of HF SDR Transceivers

Thanks for the info on that. I will definately look into openHPSDR and its derivatives.
by HighSNR
Wed Apr 10, 2019 9:33 pm
Forum: Other SDR Devices
Topic: List of HF SDR Transceivers
Replies: 5
Views: 1009

Re: List of HF SDR Transceivers

It was an experimentation radio I was looking for. Something that works with GNU radio and has a bit more dynamic range than the HackRF for instance.