Meteor M-N2 Images

Tuesday 3 June 2014

WSPR comparison between Inverted-L and G5RV

WSPR spots using 5W on 20m with my Inverted-L

I managed to get wsprx working in receive mode on my new installation of Linux Mint 16. The realtime waterfall makes it much easier to ensure that your radio is accurately set to receive in the wspr sub-band. I found that my FT920 reads about 40Hz low as a result. However, it crashes when coming out of transmit mode. Consequently, I installed the older version wspr 2.0. This also had a problem with one of the Python libraries but there was a fix documented on the website.

The waterfall used in wsprx

This means that I can now run wspr with a little more power than previously, my broadband HF amplifier only produces about 0.5W. I have been wspr'ing with 5W and the results using my new inverted-L you can see in the screenshot at the top of the page. I am amazed at how far 5W will reach. However, it is a little too easy, on my first transmission my signal was received by KK7UQ on the west coast of the USA.

After an hour wspr'ing on the inverted-L I switched to my G5RV and the difference is considerable. Although the G5RV is higher than the inverted-L (around 12m versus 6m high) one leg runs E-W and the other leg NW-SE. The inverted-L runs SE-NW pointing directly at north America. The resulting wspr spots from the G5RV are below.

WSPR spots using 5W on 20m with my G5RV

Interestingly I received VK3HAD equally well on both antennas and KK7UQ received me equally well until dusk fell when a few more US stations heard me and were heard by me. 

Along the greyline I was heard by ZL3DMH at 19016km distance.

This isn't a scientific test, by any stretch of the imagination but very interesting none the less. However, what it has shown me is that 5W and wire antennas equals QRO in wspr terms!

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