Search found 105 matches

by vk7jj
Wed Jun 20, 2018 11:39 pm
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

Hi Gio, files send by email. 73, Phil

And welcome to the solstice to everybody!
by vk7jj
Tue Jun 19, 2018 9:33 am
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

The model assumes a 10m high metal mast with an attached wire that is one half wave long at 1.8Mhz In the case of a non-metal mast the coax braid takes it's place electrically speaking. Here it is for visualisation: inv_L.png Here is the table for comparison with the loop: end_fed_bands2.png - there...
by vk7jj
Tue Jun 19, 2018 9:14 am
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

I want to thank you You sure did that Jim, thank you in turn. A large part of it is pure selfishness because I do love antennas. Antennas and discussions about them usually invoke a lot of passion, I'm sure there are readers groaning or teeth gnashing at the post. Anyway ... Wait! There is more! --...
by vk7jj
Sat Jun 16, 2018 7:22 am
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

... and they work even better on HF. Two WSPR screen dumps. The first is from a ship in the arctic circle to Tasmania transmitting on 7MHz using 0.02 of a watt. The second is from the UK to Tasmania showing successive contacts again using just 0.001 of a watt on 14MHz. RSP1A's work very well, as do ...
by vk7jj
Sat Jun 16, 2018 7:12 am
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

... here is the 432 beacon: 432.png Now for attaching the aluminium wire. I did this specially just for now :-) Timed myself and while I do have that sort of stuff lying around - I also fed the chooks while fetching the black poly. Total time taken was 32 minutes. Corner: - uses a slice of 90mm PVC ...
by vk7jj
Sat Jun 16, 2018 7:01 am
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

Had a spare half hour so thought I'd get pre-emptive: Here is the path from me to our local beacons on 50Mhz, 144MHz and 432MHz. As you will see the 53 kilometre path is a large rocky hill. The pink line is the Line of Sight path and is 397 meters below the peak. The beacons are 25 watts into vertic...
by vk7jj
Sat Jun 16, 2018 5:24 am
Forum: SDR Antennas
Topic: simple but good wire antenna
Replies: 9
Views: 432

Re: simple but good wire antenna

Make a horizontal triangle as large as you can, anything from a few meters in total circumference right up to 170m. Mounting points required: 3 - one at your house - try for the other two so as to make the enclosed area as large as possible. - height above ground is "as high as convenient"...
by vk7jj
Sat Jun 16, 2018 3:40 am
Forum: SDRplay related
Topic: SDRPlay and GQRX
Replies: 5
Views: 512

Re: SDRPlay and GQRX

Gqrx has been really great on my Mac for the last few weeks, I've come to like it a lot and use it on Linux and OS-X It was a little flaky though, more often than not after being launched for the first time in a while it would fail to find the RSP hardware. Trying to fix that I downloaded and reinst...
by vk7jj
Sat Jun 16, 2018 2:54 am
Forum: Spectrum Analysis
Topic: Spectrum Analyser - screen dumps
Replies: 12
Views: 610

Re: Spectrum Analyser - screen dumps

Here is the return loss at around 52.5MHz of my discone antenna. Many discone antennas use a vertical base loaded whip on the top of them to extend their low frequency response down to 50Mhz. For those who are not familiar with "return loss" the best way to visualise the picture is to cons...
by vk7jj
Sat Jun 16, 2018 2:45 am
Forum: Spectrum Analysis
Topic: Spectrum Analyser - screen dumps
Replies: 12
Views: 610

Re: Spectrum Analyser - screen dumps

Here is another showing the FM filter OFF and ON:

1A-FM-0.png
1A-FM-0.png (45.6 KiB) Viewed 336 times

1A-FM-1.png
1A-FM-1.png (43.97 KiB) Viewed 336 times

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