Off to CT3 land early next week And the weather appears to have played havoc with any courier deliveries, so it seems I’m rather stuck with what I can take with me.
What’s the possibilities of activating anything with an 817, 5W (for a while… maybe only 2.5W depending on thrown together ‘power supply’) and a Norcal Doublet? oh, and using ‘scaredy cat’ SSB too??
Oh, just to make it even more challenging, the 4M ‘travel pole’ didn’t even make it to being put up once, the top bit snapping as I raised it in the garden earlier so probably about 3.75M AGL maximum for anything…
I have used a Norcal doublet + my stock FT-817 on SSB for my last 8 activations. It has worked very well ranging from 10’ to 25’ above ground level (mostly 20-25’). My only problem is the feedline keeps getting shorter and shorter. The wire gauge is so small and fragile that I am only getting 2 or 3 activations before I have to strip another inch off. I say go for it and have fun!
In reply to M0HCU:
You could maybe find a couple of Bamboo/garden canes when you get there.
Tiewrap/tape them together and drop one end into the top of your Pole with some method of stopping them dropping too far down. Could possibly work if you don’t put too much strain on it.
So, if the centre is at 3.75M or so, which isn’t a great height, how
high will the ends need to be?
Hi Don,
It depends on where you want your signal to go. I am no expert by any stretch of the imagination (and will humbly take corrections). I guess we are talking about an inverted V configuration here. If you move the legs closer together (less than 90 degrees between them) the radiation pattern starts to get a little wonky with multiple lobes the closer they get. I usually shoot for a classic inverted-v with around a 90 degree angle between the sides of the antenna which gives you a more omnidirectional pattern. But your location will often dictate what you can and can’t do. Even at 3.75 meters in the center you should be able to get close to 90 degrees - the Norcal doublet is not a very big antenna. If you have trekking poles, you can use them for end supports but I have usually found a convenient bush or tree limb to attach to. Try not to sweat the small stuff and have fun. You’ll be 59 somewhere!
Don you might find the following link interesting - an article by G3RWF
The article describes an 80m doublet but the theory is of course the same when comparing radiation patterns when the antenna height is a fixed proportion of the wavelength.
My own experience of an 80m inv-V Norcal doublet suspended from 7-10m high fiberglass poles, ends 1-2m above the ground:
at its base frequency it works and tunes sharply just like a dipole (80m NVIS).
for 40m some tuners will struggle but if you can tune it it can often work better than a dipole - good range during the day and if the f0f2 is 7MHz+, fine for NVIS too.
for 30m no problem if your tuner can match
for 20m it works but you can often tell there are nulls. I prefer a 20m dipole however it’s usable
above 20m the nulls get progressively worse. You’ll get contacts but I find it seems unstable with stations often fading unexpectedly.
Thinking about it a doublet with a link (link-dipole style) at the 20m length would be interesting. Close it for mostly low band work, open it for mostly high band work. Food for thought
Do not forget that although there are more nulls on the higher bands, the lobes also offer significant gain. If you pay attention to the orientation of the antenna you can take advantage of this gain, for instance if you want more transatlantic contacts you can set up so that a major lobe is in the appropriate direction, bearing in mind that the lobes will be different on each band!
With regard to ease of tuning, a doublet of about 100-feet length seems to tune easily on every band. This is, of course, close to the classic G5RV antenna, which is 102-feet long. A G5RV with the tuner at the end of the open-wire or window line feeder is a good all-band antenna, avoiding the well-known problem of losses in the coax which are the cause of the disdain with which some people regard the antenna. It is only a few percent less efficient than a dipole on 80 metres and will even get you contacts on Top Band!
On my trip to Lanzarote/Fuertaventura 2 years ago, I had a similar setup. I used an FT817 with dipoles for 20m / 10m and a 1aH battery. Due to the small battery I ran 2.5w throughout reducing to 1w on 10m. Due to my travel pole not arriving in time I used whatever support I could find on the summit. More often than not there was no support so my friend ended up holding the dipole centre about head height. This lowly setup made 448 contacts from 12 summits. I think EA8 & possibly CT3 enjoy a privileged position in radio terms that gives you an extra whole lot of dB both on transmit & receive compared to what we are used to in the UK. Quite often I hear EA8 stations on 10m when the band appears to be dead to the rest of the world. Good luck & don`t forget to visit the indoor market in Funchal.
ps when I got home, 4 travel poles had been delivered!
don`t forget to visit the indoor market in Funchal
Yes, well worth the time.
possibly CT3 enjoy a privileged position in radio
I’ve had pileups in the past but I’ve never had so many stations calling at the same time as when I was on CT3 for my 1st activation. I should have videod it but was too excited to remember.
Thinking about it a doublet with a link (link-dipole style) at the 20m
length would be interesting. Close it for mostly low band work, open
it for mostly high band work. Food for thought
This is the style I have built my lightweight “holiday antenna”. It is an inv.-V-doublet-antenne for 40-10m with 2 times 10,8m wires for working on 40m and a link at 5,4m for operation on 20-10m. I have used this dipole with a 7,7m long twin lead line and a 1:4 balun with the internal tuner of the IC-703 on my holidays in SV8, SV9 and EA8. It works well and I can recommend to test this setup.
I find that the links really slow down the band changes. I use 2 times 6.7m wires (i.e., 44ft total) fed with twin lead to 4:1 balun into the KX3 internal tuner and it works exceptionally well on 40-10M with a broadside pattern on all bands.
What kind of twin lead are you using and how long is it?
I’m using the same antenna with 9m of CQ553 feeder (because I had plenty left) and with my K2/KAT2 I don’t need a 4:1 balun. I haven’t tried against my KX3 yet.
I’m using Wireman 562 18AWG twinlead, about 8m. It will load okay without the balun but SWR is a bit high on one or two of the bands. With the balun, it’s 1:1 on all bands.
(After repairing my cheapo, 2nd hand, M(any) F(ubarred) J(oints) ATU that refused to work after being subjected to various baggage handling companies a couple of weeks back)
Went out to my nearest hill G/WB-015, Callow Hill, this afternoon after testing my repairs this week.
Even though I didn’t extend the fishing pole fully, due to the wind, so the apex was about 6m, with the 2 x 22’ ends about 1m off the ground, the result was a very nice 30-odd QSOs on 40 & 20M with 5W from the FT817ND, the highlights being Rich, N4EX (with a 3/3 report) and Bill, W4ZV (with a 5/5 report) for my first 2 transatlantic SOTA QSOs.
Not too bad at all for a 4 way ribbon cable and a couple of bits of nylon string!
Thanks to everyone who took the time to contact me, especially on 40M, where for some reason, I had background music playing, sounding like something from a Bollywood film…
Hello Don, well done. I always wondered what MJF meant!
I also heard the broadcast station music interference in the background. A testimonial to your bits of wire etc. that you got over the QRM & BCI. Better not change anything 8-;
And the weather appears to have played havoc with any courier deliveries, so it seems I’m rather stuck with what I can take with me.
so probably about 3.75M AGL maximum for anything…
It does seem to make a difference though!
I am no expert by any stretch of the imagination (and will humbly take corrections). I guess we are talking about an inverted V configuration here. If you move the legs closer together (less than 90 degrees between them) the radiation pattern starts to get a little wonky with multiple lobes the closer they get. I usually shoot for a classic inverted-v with around a 90 degree angle between the sides of the antenna which gives you a more omnidirectional pattern. But your location will often dictate what you can and can’t do. Even at 3.75 meters in the center you should be able to get close to 90 degrees - the Norcal doublet is not a very big antenna. If you have trekking poles, you can use them for end supports but I have usually found a convenient bush or tree limb to attach to. Try not to sweat the small stuff and have fun. You’ll be 59 somewhere!