Phased 80M Array Using Spiderbeam 18M Fiberglass Poles

Photo by Slovenian Contest Club

Its pretty easy to get two of these 60′ fiberglass poles up on my two supports – and 70′ apart. I’m going to start listening to 80M more – because there is a lot more action there than 160M, and I’m starting to feel that making DXCC on Top Band is as good as it gets. Just tape a wire on the outside of each – or even hide the wire inside . . .

Photo by Spiderbeam

I like how they are black – and will blend in with the trees. Its funny, the 72′ version is $200 more than the 60′ version, so I will simply do a small bit of linear loading with the wire at the base – where I will have to trim the wire anyway. $400 extra for 12′ additional is ridiculous – and they are already quite expensive.

One of these will go where my 160M Inverted L is – so it will come down. What I can do for 160M – is create a switching situation where I simply feed the two 60′ verticals bypassing the DX Engineering DV-80-P.


The Pedersen Ray and Chordal Ducting

The ARRL Extra Class License Book contains the best explanation of why my DX Engineering DV-40-P 40M phased vertical array out performs the low Cushcraft D40 rotatable dipole up only 40′ to ZS on the Short Path at night (the lower angle goes farther and its launched in the dark at my end).

The “magic” that I experience during the morning greyline to ZS on the Long Path and with a higher angle ray – is called The Pedersen Ray. It is best documented in the ARRL Extra Class Manual, and also an explanation I received from Tom, N6BT of Force-12 fame:

“Propagation on low bands with a high angle radiator – the probable method is the Pedersen Wave. This is from a high angle launch and then is ducted across the path (long path) and then dumped out at the termonal end. Had this happen for many years when I was using a 42′ high 3el 40, comparing to N6RO’s at 140′ (which I put up). We were usually equal on LP, but short path was a different story. His antenna always opened earlier than mine and closed later.”

The ON4UN Lowband DX-ing Book (starting on page 1-17) and the Ian Poole, G3YWX RSGB Radio Propagation book (page 49) both describe this, but curiously do not call it The Pedersen Ray, but “Chordal Hopping” or “Chordal Ducting”.

A fun way to find your Antipode –

The ON4UN Book does cover this quite well, but one diagram would have really helped. Some take aways:

  1. Higher take off angles penetrate the E Layer which gets the ray into the duct
  2. The antipode from your QTH is where this ducting is most likely to occur, and year round – because when its your sunrise, its their sunset, and vice versa
  3. Ducting seems to work better at low sunspot times because either excessive ionization or auroral disturbances can wipe out these ducts. Furthermore, there are other forms of ionization that happen during a low SSN part of the cycle – galactic and cosmic rays

When Kat and I visited the Museum of the Rockies in Bozeman, we visited a great show on deep space telescopes and the new research that is being done to measure deep space rays and their influence. What is exciting is that there is still much to discover and learn, and so this is a main reason why I am still a DXer – even after “earning” my DXCC Awards.


Phased 80M Array Using 41′ Inverted L’s

I need to tweak the dimensions a little so the gain matches what is expected (3 dB end fire, 1 dB broadsided), but in a way it doesn’t matter because when you tune the verticals for use with the DV-80-P or DV-40-P, you trim to get to a certain frequency. The manual is great this way and foolproof.

The front to back is pretty outstanding. As I tune the verticals I will decrease the F/B and increase the gain. But I still expect to have 20+ dB of F/B

The pattern looks great – both Elevation and Azimuth . . .

I also found that Spiderbeam has 70′ fiberglass poles – that could be used to put a wire in – they are pricey but this could be a good alternative to turning on the radio and usually not working anything on 160M.

There are more stations on 80M, so I will start monitoring and comparing 160 and 80M more.

80M Phased Array: DX Engineering DV-80-P

I like my DX Engineering DV-40-P so much that I will most likely put up an 80M phased array as soon as we get to the bottom of this cycle – which I believe will start toward the end of this year. I would have 3 dB end fire and 1 dB broadside, which would make me competitive on 80M and 40M (with the DV-40-P and UrbanBeam) for 3Y0I.

As much as I love Top Band, its just not productive on the West Coast. Because Bouvet and Glorioso will most likely be activated during the dearth of this solar cycle, 80M would be a much more likely band to work them on than 160M, so after a couple more Q’s on 160M, I might change horses.

I can easily and inexpensively add a wire in a fiberglass pole on top of each Spiderbeam 41′ mast. A cheap MFJ 33′ light duty pole is only 3 pounds, and with a well guyed Spiderbeam push up mast, that would easily handle the top load – much better than trying to tack on aluminum.

Speaking of 80M, I’m listening to a JA who is very strong right now – and there is nothing on 160M. I think 80M will become a real band in my “quiver” this cycle bottom.

My New “DXCC”

I’ve lost 4 pounds in the last 4 weeks. Its watching the carbs and exercise. The biggest surprise is how much I love weight lifting all of a sudden. With DXCC, the goal was to make the count go up, with weight loss, the count goes down. I ride my bike to and from BART to work in SF, I lift weights and do yoga.

I’m a goal oriented person, and while retiring from DXCC left me feeling a bit “stateless”, this new healthy program has me in a similar mindset as when I was chasing DXCC. Once you get in your 50’s, you need to boost your metabolism – and I had read that weight lifting is a great way to stoke the metabolism fires. I sure can validate that!

80M Phased Array

80M Phased Vertical Array using 2 Inverted L’s

I’m playing with what an 80M phased array would look like, with shortened elements.

The first attempt at modeling this in EZNec shows that there is end fire and broadside gain (“almost” 3dB end fire 1 dB broadside), but the pattern isn’t as good as having 60′ verticals.

A while back I had a 60’vertical that used the Spiderbeam 41′ push-up mast, and then “softer” aluminum above that for another 19′. It was too top heavy, so I might look into adding 20′ with wire inside the lightest fiberglass push up mast.

I’m only designing this now, but as I said in yesterday’s post, 160M from the West Coast means you can turn on the radio and sometimes not work any new ones for months.

That one night when 80M was super open, 160M was anemic at best.

Anyway, just more fun ideas in antennalandia!

A Weird Thing Happened on the Way to 160M DXCC: 80M!

160M is agonizing from the West Coast – its really hard to make DXCC here. I can’t even imagine 6M – that would be far worse. HOWEVER, lately I have seen 80M open up like 40M does, and it offers so much more DX than 160M does.

I have no idea why, but I have always hated 80M. No – its not because of 75M – hi hi. There is no good rational reason, and now that we are dropping into the sunspot abyss, I am seriously thinking about taking my spare Spiderbeam aluminum push up masts and turning them into a phased array on 80M.

I have the buried radials (96), the real estate (barely), and the verticals. Hmmmmmmmm…….

Maybe when we hit the bottom of the cycle and when “80 is like 20M”!