I’d like to improve my receive capability here when chasing VHF SOTA and WOTA activators.
Ideally this would provide additional gain to hear 2m vertically polarized signals coming from SOTA activators in the Lake District.
I live fairly low down in Windermere, so my concern is that nothing I do is going to make much difference when attempting to chase activators where there is rock in between and me.
I’m currently using an X50 colinear. Two options spring to mind:
A better colinear. I would welcome any thoughts on whether a longer colinear with a higher gain would make any difference.
A rotatable vertically polarized YAGI. Again, I would be interested in how much this might improve my chasing ability. Obviously it has to be pointed in the right direction!
I’d like to make a decision, but don’t want to end up wasting money attempting to solve and insolvable problem!
I’d add a third option: get your current antenna up higher. That’s probably the first thing to consider.
The X-50 is basically a half wave antenna on 2m. To get significantly more gain, you have to at least double the length, to something around 2.5m or so. Beyond that, the next reasonable step is an antenna about 6m long. At that point, you’re gaining signal due to having the antenna up higher, in addition to the colinear gain.
A yagi or other beam antenna is a reasonable alternative, especially if you can almost hear the stations you want to work. It doesn’t take much yagi to achieve the same gain as that 6m colinear. Again, of course, height is good, too.
An approach that I often recommend is to try a simple yagi and see how much difference it makes. I like the WA5VJB “Cheap Yagi” designs, as they are easy to build (although I use plastic PVC pipe instead of wood for the booms). I typically use 3mm aluminium wire for the elements, with solid copper (often smaller diameter) for the driven element to make it easier to solder the coax to it. But there are lots of other available designs, including quads, quagis, stacked arrays, etc.
Then you can use such an inexpensive antenna to see how much difference it makes, and whether it is worthwhile investing in a more rugged / permanent version.
An example. I was parked in the Landie near my work, chasing @MM0VPM Alan, who was on Beinn Bhrotain, some 87km west of me.
The first attempt was 50w from my ftm-400 in the Land Rover, with a 5/8 wave whip. He was barely audible.
I took out the 100g 4 element beam and the handheld. 5w into the hand-held beam and he was 5/3 and I think I was similar.
I’ve had the same results from home, chasing both @GM5ALX Alex and @MW0CBC Denis who were both over incredibly improbable paths, with perpindicular mountain ranges between us. Nothing on the whip. Two Completes in the bag with the HT and hand-held yagi.
A decent one on a mast should make a huge difference. The way 2m waves bounce and reflect around and over hills always astounds me.
Here using an Arrow II (twin band 146/437 with duplexer, one cable for booth band)
About 0,56Kg, I’m using a audio recorder because one hand are on the antenna but you can use a tripod and write your QSO.
Here I bought this antenna because a local supplier had a good price !
You can see here my last test in V/UHF as TM15SOTA SOTLAS
The VHF DX was F4DIA at 96Km and you can see the result. 5w Ft-4ex
I have the 4 element version which is too big really for handheld use, should have bought the 3 element. I could certainly put it to good use if I bought a Yaesu 5500 alt az rotator.
According to the Yaesu X50-N spec I have, it’s 1.7m long with a 6/8th wavelength C-load on 2m with 4.5dB gain (dunno which kind of dB). My QTH is at the southern end of the Lake District with colinear at ~35m ASL on my bungalow chimney. I replaced my X50 colinear with the Yaesu 6/2/0.7m V2000A. It’s 2.53m long and has two 5/8th wavelength phasing elements with a quoted gain of 6.5dB on 2m. The increased gain is significant and I can QSO with a few locations in the north of the county, despite all the intervening LD hills and mountains, which were impossible with the X50.
A vertically-polarized Yagi, whilst having much higher gain, will of course require a rotor and additional faff.
A remote station using wired/internet access is accepted (tolerated?) by the rules at present especially if it is for your use alone. I don’t know of any remote stations using ham bands (private - encrypted or not) to access it being used in SOTA. And… conceptually and contextually, a repeater is a different thing to a remote station irrespective that they can be used for the same purpose.
A good example would be someone who lives in central London where they cannot erect effective HF antennas and the noise makes them unusable. But luckily for this ham, they are rich enough to have a nice place in the country (Burford, Cotswolds!) and have the station setup there and they control it over the internet and only they can use it. If they use it during the week remotely and then when they escape from London at the weekend they use it in-situ, then to me I see zero problems with that way of operating. Where I start to get concerned is when someone uses multiple remote stations when they have a perfectly viable station at their own home. YMMV.
Going back to antennas rather than the remoting concept, I would always favour a Yagi over a colinear, which I have never used in my 42+ years as a licenced amateur. Having said that, I have compared results at the various home QTHs that I have operated from and a short boom quality Yagi will always beat a tall omnidirectional colinear hands down. With the addition on 70cm elements the Yagi would be dual bands, then you could work Vicky when she comes up north!
In October under my horizontally polarised 2m DX antenna, I installed a dual band end mount EAntenna Yagi type EA270ZB9 on a fibreglass pole on the gable end of my house. They cost around £80 - other Yagi’s of similar type and different make are available. There are 4 eles on 2m and 5 eles on 70cm, with a single coaxial feed. It works well and also matches well to RG-213 at the feedpoint. The RG-213 goies into Ecoflex 15 once it reaches my house loft and comes outside and into my downstairs shack, with a claimed 9.35 dBi gain on 2m and 10.7 dBi gain on 70cms - the boom is only 1.2m long. The drawback is you will need a rotator and stronger mountings for it if its going on your house. I use Rawlbolts to support 20 year old “good as new” Barenco rotator mounts on a scaffold pole with a seperate mounting pole and the bearing to take the strain of the windage on the antenna mast. If you have neighbour problems, or council planners thinking the installation is is unsightly do your best to overcome their concerns and stand your ground. An Englishman’s home is his castle, and no one is entitled to the same view out of the window thatthey had yesterday… I’ll take a photo of this set up when I go outside shortly, something I ought to have done in October when it went up. I will add the photo later to this post as an edit.
73 Phil G4OBK
PS and Photos. I can’t emphasis enough the EMC signal to noise ratio nowadays. Chinese battery chargers, solar panels, central heating boilers, LED lighting, a fire alarm system in a care home near me, have all impacted over the last 8 years at my QTH on weak signal reception. In most cases nothing can be done about this type of interference as it isn’t in your own home. Unless your beam is directly pointing at the source of the interference though you can usually mitigate it, by beaming away from the source of the QRM. With a colinear there is nothing you can do to defeat it.
I’ve chased a couple of summits from work using my home rig in the past. It was only 2 or 3 though.
Can’t do it now because everything is firewalled and the office is too busy now, and it turned out easier to nip out to the top of a multistorey car park with a HT.
and write your QSO.
