Making my 160m Inverted-L into a Multi band Antenna
I recently put up a 38m Inverted-L antenna (10m vertical/28m horizontal) and tuned it on the 160m band using a home-brew Pi-Network ATU. Itβs working great on top band and Iβm really pleased with performance so far.
I decided today that it would be good to try the inverted-L out on some of the other low bands too. Since my other HF antenna is a large vertical thatβs great for DXing but, terrible for Inter-G I thought perhaps the Inverted-L would fill the inter-G gap.
![M0AWS Pi-Network ATU using my JNCRadio VNA to find the ATU setting for each band](../themes/icons/grey.gif)
Having recently purchased a JNCRadio VNA from Martin Lynch and Sons it made tuning the ATU for each band really easy. When it comes to antenna resonance I like my antennas to have an SWR of less than 1.2:1. With the VNA connected it is really easy to tune the antenna for a 1:1 SWR on a particular frequency, make a note of the tune information and then move to the next frequency and start again.
![M0AWS Pi-Network ATU Inductor with turns count](../themes/icons/grey.gif)
![M0AWS Pi-Network ATU Capacitor 1 and 2 settings](../themes/icons/grey.gif)
I marked up each turn on the large copper inductor so I could record the position of the input wire onto the inductor. I then added some markings on the two capacitors of the Pi-Network ATU for the resonance points on each band/frequency I wanted to resonate the antenna on.
![M0AWS Pi-Network ATU settings noted for each band](../themes/icons/grey.gif)
After about 40mins I had all the settings recorded on a pad ready for testing from the shack end of the coax run. Connecting my Yaesu FTDX10 to the coax I ran through each band setting checking the SWR as I went. All bands tuned up perfectly 160m through 30m and receiving of Inter-G on the bands that were active was excellent.
Wanting to test the antenna on 40m for the first time I found Nick, M7NHC calling CQ and gave him a call using just 5w output. He came straight back to me and we had a quick chat.
Nick was using an Icom IC-7300 using just 10w into an end-fed long wire from Eastbourne down on the south coast so, we were both QRP. Nick was a 5/7 with QSB and he gave me a 5/8 with QSB, not bad at all consider how much power we were using.
Iβm hoping to have a chat with some of the guys from the Matrix this evening on 60m SSB so, it will be interesting to see how the antenna performs on 5Mhz.
More soon β¦