Flower pot antenna

Steve G1KQH recently sent me an email with some useful links on how to make 1/2 wave verticals. I am sharing it with you in case this gives you ideas.

"The latest G4NSJ video pointed me to investigate..

Cheap to make for anything from 28MHz to UHF I guess.. Ideally a starting point is to make one for 2m

Gain 1dB over 1/4 Wave

Details here: 

http://vk2zoi.com/articles/half-wave-flower-pot/

You can even make it Dual band:

http://vk2zoi.com/articles/dual-band-half-wave-flower-pot/

There is even an online calculator:

https://nomonsuhendar.blogspot.com/2020/12/flower-pot-antenna-calculator.html

73's G1KQH"

HF vertical antenna

Somewhere, I have a Sandpiper vertical made some years ago. I think it is an X80. It is hardly used. It has been up briefly years ago. As I recall, it acted like a Rybacov antenna and was a vertical fed via a un-un so it provided a reasonable match on several HF bands. HF vertical antennas can pick up noise from nearby things more easily than horizontal antennas, but it might allow me access to several bands, so I might be able to WSPR on several bands sequentially. It probably won't be erected until the spring.

Wideband verticals

There are several examples of wideband verticals. These are often designed to work without an ATU but performance is compromised. Martin, G8JNJ, has done some analysis of these. In some applications, these antennas serve a purpose, although the commercial versions are not low cost. If you can accept the compromises then take a look.

See http://www.g8jnj.net/cometcha250b.htm

160m loft antenna diagram

This is a diagram showing the arrangement of my 160m loft-mounted antenna. The ground connection is made to a hot water tank (copper) next to the upstairs shack. It connects via copper pipes in the house to the external ground and works very well. The top capacity hat should be as large as possible but in my case is just a couple of horizontal wires around 1-2m longh in each case hung horizontally in the top of the loft space.

ARRL contest and re-erecting my X80 vertical

SRC X80 multi-band vertical

This next weekend is, I believe, the big ARRL DX contest and, if 10m is open, a good chance to work some transatlantic DX on this and other higher HF bands. I propose to re-erect my X80 vertical multi-band antenna in time for this contest and see what I can work with QRP. Also, another local, Ted G4NUA,  is keen to get back on 10FM, so a vertical may be better for local 10FM operation. 10m FM was good fun some years ago but activity very low these days, at least around here.

Short Marconi vertical on 136kHz - forget it!

ATU for 136kHz. Antenna connected to top of ferrite rod

Disappointing results yesterday with a very short Marconi vertical tuned using a ferrite rod loading coil and variable capacitor. ERP was calculated as around 200uW, but in reality the ERP was around 10dB down on the vertical loop (based on WSPR reports locally), so the ERP was around 5uW only. Most of this can be put down to the coil losses and to tiny current actually flowing in the antenna part actually radiating. A much more efficient antenna for the band will require a BIG loading coil outside and more wire in the air with some top loading. I could erect a 6m vertical antenna with a sloping top capacity hat horizontal section with an overall vertical rise of 10-12m. Antenna improvement could increase ERP by >6dB. TX power could be raised by 6dB. Taken together this would make a difference, but it would not meet my QRP ethos.

My conclusions are that an ultra-simple QRP approach to 136kHz TX is just not possible if one is to achieve useful results consistently.

Useful multi-band HF vertical

The Snowdonia Radio Company is offering the SRC X80, a 5.8m long multi-band HF vertical matched via a 9:1 unun matching box. This sells for just £47, which is excellent value compared with similar offerings from the Japanese manufacturers. Such Rybakov antennas offer a decent match, easily brought to 1:1 VSWR using an auto ATU, on the higher HF bands. On the higher bands performance is quite acceptable considering the compromise in size. In the latest edition of PW Magazine G6MXL reports working plenty of DX with 50-100W using one.