Showing posts with label wire. Show all posts
Showing posts with label wire. Show all posts

Saturday, March 1, 2014

Hexbeam repair completed - back up and running

I fixed the SP7IDX hexbeam today - all by myself. I probably should have asked for help putting it back in the air, but most of the work could be done solo. It took about two and a half hours in total. I had to reconnect some of the ropes that hold the spreaders apart. Also I had to remove the snapped 12 metre and 15 metre wires and replace them. The hexbeam has taken a heck of a battering from storm after storm over the winter. The whole thing needed to be tightened up and the wires replaced. It now looks good as new again and is working great, as demonstrated in this video showing the signal strength of a YL special event station:

Below is a short video I made this afternoon of the newly-fixed hexbeam. It looks much tidier now than before. It had begun to look very forlorn, and was practically unusable. The weather this morning was very pleasant - bright and dry - although it has clouded over somewhat this afternoon.


Here is a photo which was taken during the repair work while I was on the shack roof:
The hexbeam leans over nicely onto the shack roof for easy access for repair./

Tuesday, October 15, 2013

The challenges of 80 metre operation from a small garden

Regular readers of this blog will already know that I operate from a small garden. You will all know that this hasn't prevented or deterred me from working DXCC on every band from 80 metres through 10 metres. My lowly Butternut HF6V, which is 26 feet tall, and ground mounted in a corner of the garden near the wall, has enabled me to operate in a limited capacity on 80m. Through last winter, especially as a result of my participation in the CQWW CW contest in late November, I was able to finally get 100 countries confirmed on that band on LoTW.

But I have never been able to enjoy good operation on 80m because the Butternut is too short and therefore limited in what it can hear. It gets out reasonably well for the DX stations, and the low angle of radiation definitely helps.

A photograph of my nested inverted vees, with labels.
Just this week, I decided to put back up the 80m inverted V, off the same feedpoint as the Vees on 30m and 40m. From previous experience, I knew this would involve some serious dog-legging. (For non amateurs, this means making the wire antenna "turn a corner", so to speak, because there isn't enough room for a straight run of wire that's 66 feet long on each leg. One leg - the "reflector" - is able to get a run down along the side of the house, as far as the gate pillar at the front, although about three feet of it still needs to be dog legged.

The other leg - the "transmit" leg - runs down above the back wall of the garden, and then dog-legs up the side wall of the garden to a point at the back wall of the house under the eave. From there, it is dog-legged again by about three feet and tied off. And the mast (insert word "pole" here!) is only 30 feet at the apex.

It's far from ideal, I know. I bet some of you are trying to picture this all in your head and wondering how I've managed to defy the laws of physics, and indeed the laws of effective radiation of RF fields. So how's it working?

The reflector leg of the 80m inverted v dipole runs down
between the houses and is tied off (dog-legged) at a gate pillar.
Here's a summary of the contacts made last night on CW using just 100 watts: PI4EME, US8UX, EI3HMB, HA5OV, IK6DIN, YU9CF, EI6IL, F5TVG/P, HB9FBA, EI7BA, S51FZ, GM3ZLC, EI2EO, UT8MM, G4LEM, PA1MUC and HB30OK. So it's getting out, as far as Ukraine. Hardly a comprehensive test of its abilities, but the reports coming back were generally 579 or 599 or 599 plus! The previous morning, I had worked N8NA on 100w on CW, so that wasn't bad either, but it's likely that he's got bigger antennas than me.

Time will tell if it's up to the job of making more distant contacts. I will run 400 watts when conditions improve and the band quietens a bit - the QRN here can be s9 at times.

Interestingly, the 80/40/30m nested V system also has some resonance on the lower portion of the 160m band. When I say "some", I mean about 3:1 at best, maybe 3.5:1. It might allow me a limited amount of operation on that band over the next couple of months. I may figure out a way to tune it better for 160m. We will see.

In the meantime, I will keep you posted as to the performance of this compromise antenna system.