October 30, 2014
Every now and then I have to remind myself that the phased verticals are really worth keeping up vs. a high dipole on 40M. The reason? The high dipole does look like it has more gain, but on 40M – the lower takeoff angle and the decent front to back means the “apparent gain” (what the signal sounds like) will be at least equal between the two. The Inverted Vee is a real stinker for DX – but would be an awesome antenna for say, WAS or checking into state side nets.
Its a shame HFTA can’t handle verticals – because this would tell the rest of the story.
One of the best reasons to keep the phased verticals is that I have a second antenna to use for ATNO’s, should something go wrong with the 20M 3L full sized yagi – or the support that its on. So – there is the “backup” aspect. Secondly, maintenance is FAR easier on the ground than up in the air – even though cranking the AB-577 up and down can be done (with antenna repairs included) in about 1/2 day. I have learned to take my time when doing repairs – because there always seems to be something else that needs to be improved – so its worth taking it slow and deliberate.
Which reminds me – my tower, the AB-577 can be rotated from the bottom, so – if my rotator ever stopped working, I can easily turn the yagi toward the ATNO that I need. Typically, ATNO’s come in on one path or the other – so the worst that would ever happen is that I would have to hand turn the antenna twice a day, but that would be very rare. Usually I just park the antenna in one direction for an ATNO.
I also have backup parts for everything – a backup rotator, lots of aluminum and a second Array Solutions Stackmatch II. I even have extra coax and rotator cable, so if anything goes wrong – I can fix it within a half day, easily.
One thing I like about the phased verticals is the ability to instantly switch directions – NE, SW and SE/NW. I like this MUCH better than using a rotator.
Today and tomorrow I will be putting up another antenna on my second mast – which is a temporary “Field Day” style mast – and will leave this up for FT4TA and K1N. The next announced DX-pedition will be VK0EK. There will be a few other new one’s to work in 2016 – but its too early to count on anything happening beyond VK0EK at this point. But I expect two to be activated in 2016 that I need.
October 28, 2014
I have figured out one easy and great way to get some gain for FT4TA on 17 – 10M. Well, up to 3 dB gain on 10M, 2 dB of gain on 12M, and regular dipole gain on 15 and 17M. The 17M element is aluminum, and the other 4 elements are wire. They all run side to side. The takeoff angle is 20 degrees for 17, 15 and 12M, and 15 degrees for 10 Meters.
I asked my friend, Dean, N6BV about the gain – and he thinks the 3 dB gain (11.33 dBi) is because the 17M element acts as an Extended Double Zepp. And the size of the 17M element (25.9′) does in fact fall within the 10M band as an EDZ. I’m not sure why there is some gain on 12M, but that’s a bonus I am more than happy to accept.
It is a simple fan dipole – all elements are horizontal and they are 6 inches apart. The feed will be a 1:1 current choke. With the antenna only up 35′, this is a great and easy solution for both FT4TA as well as the upcoming K1N Navassa DX-pedition.
Just for laughs – I might see if maybe adding a reflector for 17M adds any F/B to any of the bands above 17M. If it does, then the antenna will be a 17 – 10M 2 element yagi when I am done with this! Imagine 4 dB gain on 17M and 2 or 3 dB on the other bands – that would be awesome. Stay tuned – I will be doing more modeling tonight – but alas – its time to run to work.
October 27, 2014
(Click on the images to get a larger / readable view) . . .
I enjoy designing and building antennas more than working DX, but I use the DXCC program as a “marker” or way to test my antennas in a competitive situation (pileups) and see how well they work. I have submitted applications and earned awards – because I do find that level of participation useful. I only chase 160M DXCC and Honor Roll #1. I also know that propagation predictions are “iffy” – but I enjoy them as others enjoy gambling at slot machines – hi hi . . . I change my antenna farm at least 4 times a year, and tweak something on a monthly basis. So as you can see – tinkering is the number one reason I stay active in ham radio. The learning is what drives me and keeps me active.
If I didn’t like tinkering so much – I would have a SteppIR yagi that works on 40 – 10M for sure. Not the largest though – because I love my AB-577 military mast and have become a military surplus junkie when it comes to “towers”. They are just way too cool . . . . And the SteppIRs are heavy. The other reason I do what I do is that I can fix anything myself and do it in hours – not days or weeks. No need to wait for UPS – hi hi. This means my “back up plan” is in my full control. I have backup rigs, antenna parts, etc, etc. Trusting one antenna to do it all is IMHO dangerous. I’ve never run over to a club or friends station – but my neighbor an world class DX-er, Oliver, W6NV has offered his station for my use. I should have taken him up on his offer for me to try to work FT5GA – Glorioso. He worked them and I didn’t – and he is only 5 miles away from me. Ugggh.
I am very lucky to have had such mentors as Dean, N6BV, Tom, N6BT, Jim, K9YC and Stu, K6TU in both the antenna design and modeling and the propagation prediction areas of my ham radio endeavor. I have also have been very lucky to have my very close friend, Dr. Bob, KK6EK as a mentor in DX-pedition planning. I have enjoyed many discussions with Paul, N6PSE and enjoy all of the “point / counterpoints” along the way. Its been a blessed adventure, and these guys are my “homies” right here in Northern California!
I am going to start this propagation analysis using Dean Straw, N6BV’s propagation prediction tables. The main reason – he shows the strongest paths – LP or SP, and by denoting the LP path using an (*) asterix. He also shows all other areas of the world at the same time – so in a sense – you get everything all in one chart. 20M is listed above, and it surely reminds us of the long path direction – and especially in the AM gray line – which jives with a very strong South African path that I have experienced all summer long – and even going into this fall. Even though there seems to be many SP openings during the West Coast night fall, I will bet I make a Q on 20M at 1400Z on the 20M LP. However, since I have worked E3 recently on 20M SP – as long as FT4TA looks for West Coast on our SP at night – it does seem quite possible. The big problem – and this is a theme throughout all of these predictions – is that the rest of the world has 24 x 7 stronger openings. FT4TA operators will simply have to call “West Coast Only” quite a bit to combat that and stick to their guns.
Dean shows 17M as a “money band” for the West Coast – with a lot of nightly LP openings. Now that would be awesome – 17M LP because the rest of the US will be into darkness. The problem is that EU has an even better shot – so it will be very important for FT4TA to call for “West Coast Only”. I hope they even have one station dedicated to ATNO’s on one “money band”.
15M also looks great. These charts are helping me make a big decision. One idea is to build a 17-10M rotatable dipole and put it on a mast that I have up that can go at least 1/2 wavelength on 17M. This means I will have full QRO ability on 160-10M. I do expect at least one QSO on one band between 40 and 15M. I can’t imagine the FT4TA team won’t try hard for West Coast since they have openly and publicly stated they would on their web site. We also have an awesome pilot on duty – John, K6MM, so I expect that as long as I do my part – good things will follow.
VOACAP online predicts 20 – 10M to be “money bands” for the West Coast, with 15M and 17M being the best. It does not offer much hope for the low bands – but it is close to what Dean, N6BV’s propagation charts say – and this is fully to be expected. Personally, and based on my past experience working all of the 3B’s, Madagascar and TO4E (Europa) during a similar time of year with similar conditions (the downslide of Cycle 23), 40 and 30M during the morning gray line Long Path must be paid attention to. In fact, I’d bet on these, plus 20M during the morning gray line – based on what I have heard personally all summer and even this northern hemisphere autumn.
This is Stu, K6TU’s propagation service analysis, and I think I will mostly ping pong between it and Dean, N6BV’s – since Dean shows the LP – which for this DX-pedition I think will be very much critical. It does seem to jive with my on air experience given the time of year, solar activity and past actual QSO working experience. I fully expect that we will hear them on 40 – 15M and that 20, 17 and 15 will be quite good. Interestingly, Stu predicts 15M as the money band. With 10M opening nicely this past weekend – who knows, maybe 12 and 10M will be on fire. I don’t expect 160 or 80M so much, especially because the JA’s and OC, VK/ZL should do better during mutual darkness, and EU holds dominion 24×7 and on all bands! Maybe there would be a small sliver of time on the West Coast gray line – but I won’t count on it.
So – I have a small dilemma – put up a 17-10M rotatable dipole – or put up my 15M 3 element full sized yagi. Luckily, I have a telescoping support and rotator up waiting for my decision – and I have all of the antenna elements already built. I might even make a 15/10 or 17/12M 2 element yagi and get two bands for the price of one. Since I already have a full sized 3 element 15M yagi – adding 10 would be a breeze.
I have 3 or 4 days to do this – this is a fun “contact sport” – eh?
October 23, 2014
The DX News for rare ones keeps coming. I need to go on vacation more often! Yesterday, the announcement that K1N – organized by the KP1-5 Team will activate Navassa as early as January 2015. I expected that the KP1-5, who did a superb job with K5D would also activate KP1 – sooner or later. I just did not expect it for about a year – due to the fact that there is so little time to prepare. This time frame is very good news – (for many reasons).
The East Coast and Central states will have 24×7 band openings with S9 crushing signals. The West Coast will have plenty of opportunities, but I am guessing that we will have to wait a bit for the K1N team to work through the East and Central “walls”.
On 20M, at 0100Z, there is a time when EU will be quiet and the JA’s will have weaker signals. Almost all bands have this same sort of pattern – but I do expect that this operation will be a lot like K5D and HK0NA.
Tromelin – coming up just next week will require some extra “strength” and effort for sure. I’m betting on the lower bands on the morning grey line – and maybe even that weird 3:30 AM (PDT) 20M opening that lasts about 1/2 hour for the West Coast.
We should be getting more details on who will be on Bouvet, but for me – my “needed” list is looking pretty darned great:
October 21, 2014
The model above shows the pattern for a 60′ aluminum vertical that then has a linear loading “stub” made from 15′ of 450 ohm ladder line that drops down along the vertical to 45′, and then which is connected by a 45′ “stinger” – or Inverted Vee “tail”. The part that has the stub does affect the pattern – and causes a sort of shadow at a high current point. Here is a close up of just that section:
The biggest benefit is that I can maintain resonance without a heavy coil at the top of the vertical. But I’m not too crazy about how the pattern is affected. Here is the same vertical, but with a coil at the top:
This is a much nicer pattern, but it then becomes an antenna that is a lot like what I have now – except that it introduces a high angle horizontal component that sort of acts like a hat – but not like it does with my present antenna. If the coil can be set up to trap at 80M and then let the rest of the wire add in resonance at 160M, maybe its of value.
This idea – just a regular Inverted L with a tiny “tail” hanging down at the far end (meaning a little linear loading) works the best on 160M. Resonance is achieved on 160M, and the pattern is still a low angle vertical (DX) pattern. HOWEVER, the pattern on 80M ends up being an NVIS “cloud warmer”.
So – this is the first and most compelling reason to stick with what I have now – and just improve on the variable capacitors ability to handle higher voltage. And then – after replacing the capacitor – just keep the power down to maybe 1 KW instead of 1.5 KW?
I will have increased my power from 500 watts to 1 KW – and will have done it as efficiently as possible and will have a good DX pattern and angle on 160M and 80M. Furthermore, 1.5 KW on 80M will be no problem. Here is what my present hatted vertical looks like:
And this is the same pattern on 160M and 80M. Mechanically, it ends up being the best of all worlds. Trying to keep multiple “tails” up in trees where squirrels have constantly eaten through my antenna rope leads me to just replace the capacitor . . . .
October 21, 2014
Besides enjoying the gorgeous autumn colors here in the West, the DX News engine is running at full “fever pitch”:
I could very well be two away from DXCC Honor Roll #1 by Visalia of 2016. Now this is something I did not expect – but again – I never expected to go from 325 to 331 in a year – my last year to make Honor Roll – 2012, and where the 331st QSO was New Years Evening, 2012/13. Its autumn 2014, and who knows, maybe I could make Honor Roll #1 in less than 20 years? That would be pretty darned cool.
And this is why I stay in the game . . .
October 19, 2014
I have figured out a way to get a “nearly resonant” 160M antenna and a resonant antenna up for 80M. I can have two separate wires – or maybe one aluminum and one wire vertical and use a Stackmatch II switch to switch one or the other. I have two trees that can be used – one that will give me 70′ on 80M, and the other that will give me about 100′ on 160M – so on Top Band, I will need to add some L, C or both. But it will be much more efficient and have better bandwidth than my short hatted lowband antenna – where the voltage high point requires a very high voltage capacitor. Mechanically, this new antenna idea should be better than the big capacitance hat – that makes the short vertical VERY top heavy, and could be subject to some issues in high winds.
The only issue with the new antenna would be squirrels eating through the support rope – but getting this much height on a lowband vertical on a small lot is tricky.
One other idea would be to attach a 30′ Jackite pole on top of a 40′ aluminum vertical to get resonance on 80M, and then just run the 160M wire as more of a “slanted” Inverted L. The entire antenna could be telescoped up from the base – with a ladder leaning against the base support as I have it now. It won’t be top heavy, and it tapers and gets lighter at the top – so can support 70′ height easily.
I have all of the components to experiment, and it seems that the best idea so far is to not have a flat – horizontal “tail” – or a tail that drops back down from the top of the vertical – as you would with an Inverted L or other variation. Keeping the vertical always going up – even on a slant seems to really be the trick.
Oh – don’t worry about the picture showing the feed at 50% of the elements – I am using an old PC that has the demo edition of EZNec – which is pretty useless, but it at least shows the pattern OK.