Search found 51 matches

by HighSNR
Thu Apr 09, 2020 10:29 pm
Forum: Antennas
Topic: Antenna Coax Question
Replies: 4
Views: 974

Re: Antenna Coax Question

Rg174 should have less than 2dB attenuation for shortwave
by HighSNR
Thu Apr 09, 2020 6:43 pm
Forum: Antennas
Topic: Antenna Coax Question
Replies: 4
Views: 974

Re: Antenna Coax Question

Freq?
by HighSNR
Mon Feb 24, 2020 9:35 am
Forum: Antennas
Topic: Simple but effective DIY Civil and Military Airband Antenna
Replies: 8
Views: 9030

Re: Simple but effective DIY Civil and Military Airband Antenna

There isn't much material in this build that is likely to add loss(at this frequency) to the antenna, so in this case, I would expect S11 to be a fairly good proxy for the true performance.
by HighSNR
Mon Feb 24, 2020 6:26 am
Forum: Antennas
Topic: Simple but effective DIY Civil and Military Airband Antenna
Replies: 8
Views: 9030

Re: Simple but effective DIY Civil and Military Airband Antenna

Hi Mike, Great writeup. I haven't seen this style of antenna before. It's a very interesting design. The only thing missing from your blog is any final measurements of the antenna performance. The frequency is right in the sweet spot for a £50 nanoVNA. The S11(vswr) will give you an excellent idea o...
by HighSNR
Thu Jan 09, 2020 6:35 am
Forum: Antennas
Topic: a quick queation about atennas
Replies: 1
Views: 2994

Re: a quick queation about atennas

Hi It's difficult to know the exact length to tune a telescopic antenna. The cable and ground plane play a big part. 1/4 wavelength is a good start point. Unless you have a VNA, you can just tweak for optimal reception. It all depends on how critical it is to extract those last few dBs of sensitivit...
by HighSNR
Sun Nov 17, 2019 9:35 am
Forum: Antennas
Topic: Looking for recommendations for mobile, wide band, rx only antennas.
Replies: 2
Views: 2358

Re: Looking for recommendations for mobile, wide band, rx only antennas.

Is this an antenna array? For DF for instance.

Or do you just need multiple channels that don't need to be coherent? Kerberos would seem like overkill.
by HighSNR
Fri Nov 08, 2019 8:05 am
Forum: Antennas
Topic: Suggestions for antennas to use with four channel coherent RTL-SDR
Replies: 8
Views: 4123

Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Dipoles would work fine. Or you could have a sleeve dipole, if you only want the antenna to protrude out in one direction(to avoid snarling up on landing for example). One thing worth thinking about for use with Kerberos is that you need to have the antenna well isolated from the cable. That is, you...
by HighSNR
Thu Nov 07, 2019 1:49 pm
Forum: Antennas
Topic: Suggestions for antennas to use with four channel coherent RTL-SDR
Replies: 8
Views: 4123

Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Can you elucidate on 'airborne platform'? Is this a fighter jet, microlight or a hot air balloon for example? Where on the platform do you envisage placing the antennas?
by HighSNR
Sat Sep 14, 2019 6:07 pm
Forum: Antennas
Topic: Antenna for SDR
Replies: 3
Views: 2894

Re: Antenna for SDR

I sell some ultra wide band antennas that cover a whole variety of interesting frequencies. I think they are a good start for exploring a while range of bands, but if you have any specific target applications you will probably be able to find a better narrow band antenna. https://www.tindie.com/stor...
by HighSNR
Sat Aug 24, 2019 9:55 am
Forum: Antennas
Topic: antenna related information and guidance for asking questions to improve chances for an answer
Replies: 6
Views: 9370

Re: guidance for asking antenna questions improves chances for an answer -proposal for a sticky post

All seem reasonable to me. I'm sure there lots of other info people could volunteer too. Just telling us the frequency ( in Hz) is a big help. Don't make us research that esoteric signal that may even be specific to your country. Cable lengths and types used is also worth knowing. What type(RG numbe...