May 25, 2016
At 1.822 my (ungrounded) AB-577 with DXU-32 up at 50′ and another 5′ pipe going up for the boom truss, it ends up looking like a pretty super 160M antenna. The fact that the SWR is 2:1 at 1.822 is a minor miracle. But what about on receive?
Here are readings tonight of a nightly round table up in the Pacific Northwest:
- MA160V – S9 +10 db
- RX Loop – S9 +10 dB
- AB-577 – S9 +20, and sometimes more
This is like 55′ hatted vertical – fed against 96 buried radials and the hat has 5 elements, a 28 foot boom and two elements that are 45′ wide and 3 others that are 36′ wide. This might have the effect of adding such a large hat that makes it resonant in the band. Not sure.
The only issue besides it being only 10′ from the house is that with two baluns on the DXU-32, if I put any real power on this baby, who knows what damage could happen if RF got through the 1:1 current chokes and then back down into the Rat Pak switch. I have transmitted with very low power just to see how a little bit of tuner dials it in perfectly, but am afraid to crank up and real power.
HOWEVER, its a damned great RX antenna on Top Band. Wow – success this early in the Summer (technically end of Spring). This might be a great summer!
May 24, 2016
The good news? I heard several JA’s calling VK9NT, so its a good thing to hear any Northern Hemisphere DX on Top Band this time of the year.
It looks like Norfolk Island (just North East of VK is not itself in a heavily lightning prone area) this morning. No lightning all the way to the West Coast, and also clear to JA. Several on the ON4KST chat said the band was just plain crummy today, although VK9NT did work several JA’s. I just found out he was only running 100 watts, so no wonder – I am sure max power will be needed for any serious DX in the summer (their oncoming Winter). But it also does seem like the N – S path was open at least a bit this morning.
One thing that I always notice is the noise on Top Band starts howling as we approach sunrise. The small loop is swamped first and then the MA160V. The MA160V is probably more than 20′ away from any neighbors property and during complete darkness the little loop actually had less noise and I could copy the JA’s better on it. As soon as it got lighter out – the MA160V was superior. This is very significant, because when I worked FT5ZM and VK0EK on 160M it was just minutes before daylight, although both were still “enough” in the Northern Hemisphere Winter or Early Spring. What this tells me is that the D Layer much more rapidly “heats up” and the band shuts down much quicker in the Summer than Winter. It will be interesting if there is even any real “enhancement” in the Summer months.
The lightning is also a huge factor. Luckily, there is the last DX contest to monitor – the CQ WW CW Contest. I doubt there will be much Top Band activity, but I sure hope I’m wrong. I think I will get the AB-577 wired up to be a RX antenna after work today – maybe battling the summer noise is a really good time to work on this.
I just noticed how important it is to turn off the RX preamp after sunrise. I can “hear” the D Layer forming as it gets lighter and the give away is the rise in noise. This means it seems like you almost have to turn off all preamps during the “enhancement”. I also found that tuning or detuning the little loop using the MFJ-959C in the shack helps quite a bit. This is because the little loops frequency is extremely sharp. I also turned down the RF Gain and turned up the AF gain – to “prolong” hearing some guys that are on 1.875 every morning.
Its all the little things on Top Band.
UPDATE (from the “embarrassment department“):
As soon as turned off my big screen monitor, the “howling” noise went away. It seems as though the MFJ-959C is ultra sensitive to the monitor – since they are about 1 foot apart. When I am calling I certainly don’t need the monitor on – but it does make a good case for using a laptop with quieter screen. HOWEVER, the big screen is so useful and enjoyable its easy enough enough to turn it off when I call the DX on Top Band. The noise gets worse as we approach sunrise – probably because the signals are down as the D layer builds. The noise isn’t nearly as bad on the MA160V – so it goes to show how ANYTHING along the cable(s) from rig to antenna can pick up all kinds of man made noise, and it even changes over time – darkness to dusk and vice versa.
May 24, 2016
Ahhhhh, this is what I love about summer. No hurry to do anything antenna wise, and unlike past years where I’d take any excuse to start throwing wire up in trees, I now like to think, dream and collect a little data first. This means what I end up choosing will have the highest probability of success.
I can very easily add a coax jumper from a port on the Rat Pak remote switch down to the AB-577 and radial field. I’ll try that this weekend – maybe even sooner and start AB testing. I have one last port in that switch – so that’s great, and its FREE.
May 23, 2016
Sadly, the fellow who wrote this book, Grant Bingeman, KM5KG passed away a few months back at the age of 66.
This little book is quite interesting. He covers an antenna that is called a “Paran”, which is essentially two shortened verticals phased as a sort of voltage divider. The resulting pattern is omni-directional, but the efficiency is improved substantially because you have just doubled the radiating area.
That’s when I thought – hey, I can phase two MA160V’s. I got some advice on modeling this from Jim, K9YC, and found that what Grant talks about could work:
The loss is 5.59 dBi with two verticals spaced 35′ apart.
With a single vertical, the loss is now just about 8 dBi.
This means two would be more efficient, maybe by 45% – but I’m not sure. The pattern remains the same – its omni – directional.
With a Christman Feed, there would be very little directionality, but with a really weird phasing of 165 degrees – you could get something worth trying. I’m not sure if that’s even possible or how to do it just with coax cable – bu I’ll look into it. My guess is that no matter what EZNec says, there would be too much interaction which is why EZNec said that 165 degrees would give a nice 13 dBi F/B, but with horrible loss. This tells me my model is not right – its too simplistic, but I am sure 1/16th spacing of two short verticals on TX is an omni directional antenna, and that’s it.
HOWEVER, on RX, I think trying phasing like the Hi Z RX antennas could be useful.
My second idea is something I’ve already done – and that is to feed my AB-577 tower fed against a radial field of 96 buried radials (which are separate from the 44 buried radials on my MA160V). The antenna is like a 50′ version of the MA160V but using the N6BT DXU-32 as an absolute massive top hat:
May 23, 2016
If I remember correctly, Cycle 24 performed about as expected on the upswing, but has under performed projections on the down swing. That still did not stop DXers by any means, and the most astute put effort into their antenna system. Many went from a low dipole to a hex beam or a yagi of some sort, and reaped the benefits. Others just whined and blamed, which was unproductive.
During the very long low segment of Cycle 23 – after 2005 until about 2011, I worked 18 ATNO’s and got on Honor Roll. Since I did it in one solar cycle – 11 years (even though Cycle 23 stretched out to what ended up being about 12 or 13 years – and with one of the longest low parts of a cycle ever):
I’m trying to remember, but I think the very worst part of the cycle lasted 3 years – where the high bands were just about dead. Zero sunspots and low SFI. At that time I struck back and built a very decent 2 element 40M phased vertical array, and that kept DXing alive for me. I will never forget the 40M morning and evening opening to the “double header” VU7 and VU4 DXpeditions. I just got home from working in San Francisco and right at sunset, the VU7 came up out of nowhere, lasted 1/2 hour but maybe 15 or 20 minutes really worakble, and then faded back down into the din. A high dipole would have achieved the same results – as long as it was pointed broadside to the DX. Since my phased array was broadside to the DX, I can’t say if I worked them long or short path – but I think it was long path since that was the direction of mutual darkness. Up to that point I was on a 200 watts or less and wire “jag”, but finally had to cry uncle when I started missing DXpeditions by being so “pig headed”.
But even the low bands require some solar activity or the MUF drops down to a rediculous frequency. Luckily, 160M doesn’t seem to mind much as far as low solar activity goes! Top Band offers the most “magic” of any band, perhaps more so than 6 meters.
I remember silly buggers on DX Forums asking me why I was in a rush to make Honor Roll, and all I can say is that you really (really) have to make hay when the sun shines. Some of the entities I worked are no longer active and won’t be for years, and yes, I missed these (and had to “make them up”):
- South Sandwich – my mistake of not even knowing they were a separate entity cost me 14 years
- ST/0 – my low Moxon didn’t cut the mustard. I had to wait about 3 years to make that one up
- E44 – my two element wire beam just didn’t get over the nearby hills. I had to wait 5 years to make that one up
Thank goodness I worked Syria, North Korea and Turkmenistan when I did. And the one’s I just didn’t snag – (and YES – it was MY fault, NOT the DXpeditions fault):
- 3Y0E – Petrus was on the island and calling CQ. Right as I was calling him, he had to QRT – his tent was being blown apart. My bad. I just didn’t get the work done. Yes – “tough luck sonny boy”, and is “one that got away”
- FT5GA – I never heard them – but just like the others that I missed, my low Moxon at 30′ high was just a rotten antenna. Moxon’s are great – but you need to get them high and in the clear. Mine was so close over the roof its amazing I worked all of the DX that I did with that thing. Again – “tough luck sonny boy” – just another one that got away
Yes, I COULD have been on Honor Roll #1 in 15 years, but I just didn’t get that job done. And you bet yer sweet dollar that it matters – the idea that “you should savor the journey” is not my cup of tea. Not even because I missed out on DX from 1973 – 2001, but because life got in the way and I was off the air from 1977 – 2001. Actually, I don’t savor the award itself – but the things I did to get the award – which is my Antenna Journey.
All while I was working toward my goals I learned that NO DXPEDITION OWES ME A THING. I OWE THE DXPEDITION the courtesy of having a good antenna and operating skills to get in their log. Sure – I want a decent chance, but guess what? If someone like Petrus or the FT5GA guys went there – and all I had was a wimpy antenna, then its MY problem and fault – not the DX-peditions. There were others in the SF Bay Area that did work them. And running to a club station is fair game – even though I chose not to do that – and many days wish I did. I was pig headed . . .
I did work a scientist (Jean – FT5WJ) when he was on Crozet with 100 watts and a vertical. This is the same set up as Petrus had. So there is no reason why I couldn’t have worked Petrus except it was MY bad timing. And many in the SF Bay Area did NOT work Jean. Comme ci comme ca . . .
When I missed a DXpedition, I was angry. Yes, the first knee jerk reaction would be to blame the DXpedition, but I bit my tongue and then directed the “energy” inward. I started asking what I could do to overcome what was MY shortfall. And the answer was a “journey through antenna-land”. I spent the next 10 years giving antenna and propagation presentations, and through that effort very quickly made Honor Roll. That’s THE reason why I made it more than anything. The only reason why this award is actually an award is because I can be proud that I overcame my own stupidity to forge ahead and get past my own pig headedness. (Is that a word?). I guess you can say its a “triumph of the will”.
Its always been ALL about the antenna, and a modicum of half decent operating skills. And yes, teams formed and did the hard work to get there. Its a cooperation not an entitlement.
My current antenna journey is all about Top Band. I have the same obsession about 160M as I did all of the higher bands combined. Making DXCC on 160M from the West Coast will end up being very close to the time it will take me to make Top of the Honor Roll. And its funny – I don’t care that we are entering another long low of a sunspot cycle because I need a whole lot more to make DXCC on Top Band (25) than I need to make Top of HR (2).
I actually can’t wait until these solar disruptions stop and the sun goes silent for a while. I WILL get these last 25 – and it will take 3 or 4 years I am sure. I will make DXCC on 160M right during the low sunspot Cycle 24 years. So this time – LOW will be a HIGH for me. And I will make HR #1, but it probably will happen after DXCC on 160M.
Its kind of an amazing statistic – that Top Band DXCC from the West Coast takes as long as HR or even HR #1. My only competition is myself . . .
May 22, 2016
I just started a matrix of Top Band RX antennas. In the past I put something up just because it looked like a “silver bullet”. None were, but the learning was well worth the effort. I’m going to combine my past experience, the pro’s and con’s and some new data to turn this into my summer project.
We are launching the product and web site at work – so my time will be sequestered by work this summer. But in the hours on the weekends that I have to play with – I will be out in the back yard and down in the creek bed (perhaps).
This summer gives me lots of time to think and play – which is always nice since once Fall rolls around – the attention turns to being on the air – not out playing antennas as much.
- Cost is important – and there is a big decision – phase two small RX loops with the MFJ-2016 – which would cost $200 and would let me eliminate noise. It would also let me move the antennas around – so its the most flexible choice. In fact, I can phase these and set them up for the ultimate in directionality. No other choice comes close.
- The RBOG seems to have great SNR and F/B – but would not work at all for the Caribbean and South and Central America – and these areas are probably the most likely places to help me get to DXCC on Top Band.
- The HiZ could actually be set up to be somewhat moveable and would have great SNR and F/B, but until I try moving the small loop to see if I can eliminate the neighbors noise problem, its too scary to basically end up with another noise swamped RX antenna. Also – 18 – 24′ verticals might be “2 too many” antennas sticking up on my property. Unless I could use black wire for the verticals.
May 22, 2016
One of the Diablo DX-ers, Scott, K2CUB joined the VK0EK Team and helped handle many support tickets. Scott is an avid Low Bander, and he and I met at Visalia and we discussed 160M RX antennas. I must have mentioned that my K9AY Loops were swamped with the neighbors noise, and Scott suggested that I look into an RBOG – or Reversible Beverage on the Ground antenna. The first thing I found on a Google search is Carl, K9LA’s excellent paper:
From this paper I found two things especially encouraging:
First of all, the description of this antenna – that it is especially good at reducing nearby man made noise was BINGO number one for me. The second is the chart above – where Carl compares the RBOG with the SAL-20 RX array. The SAL-20 is not that much different from the K9AY, so for my purposes, his comparison test is almost exactly like my situation. In fact, his Inverted L is pretty much the same as my MA160V, so a “direct hit”. The RBOG sure looks like it is a leap above and beyond the old K9AY that I had – since the SAL-20 is supposedly a bit better than the K9AY. And in “enough” cases, the RBOG is significantly better than the TX antenna – which would be the same case as my MA160V.
The pattern is more like a beam than a K9AY and its cardioid pattern. The only issue here is that my RBOG would end up being N by NE and S by SW. It would be useless for the Caribbean and South America – two very important directions for getting to DXCC on 160M, BUT, it would open up the Polar Path to EU – and the closest I’ve worked to EU on 160M is CU2KG – Azores. My friends tell me that’s not EU – but AF. I wouldn’t even call it AF – its only 5,000 miles away from Orinda – which pales in comparison with VK0EK and FT5ZM as far as distance goes. But with CU and V5 in the bag, I think it shows that as we slide down the cycle – and when we get to solar minimum, 160M will only get better.
For the S by SW direction – there is still good opportunity to work some new ones on 160M.
The cost of the KD9SV RBOG gear and 200′ of wire is about $320. Of course the biggest problem is that I would have to lay this wire down along the creek bed that makes the hypotenuse of my property line. That is only about 150 feet – so I would have to run it down past other neighbors properties along the creek. Since I could rake leaves and junk over the wire (nearly buried), this is doable – and could even keep it out of the deers hooves (this is a heavily deer traveled area).
I’d have to run 100′ of quad shielded RG6, but it looks like the feed point is just one end:
My strong gut feeling is that the HiZ system or anything that is vertically polarized will have noise issues – and so in many ways, the RBOG looks like a thing to seriously consider. I used to live on 5 acres in Lafayette – and I could have had beverages running in every direction. I was just starting as a DXer then – so the higher bands is where I was at. I remember thinking how hard it was to work DXCC on 80M, so that is now pretty funny. Oh well – that’s the challenge – to do the best you can with your own particular situation.