Inverted Vee Linked Dipole vs. Endfed Antenna (Part 1)

[DC8YZ]

Hello Sota community, I use an Inverted V Linked Dipole for 20m and 40m to activate Sota. However, at some Summits there is no possibility to set up an inverted V with 10m leg length and central suspension. (just in the forest). That’s why I’m currently thinking about end-fed antennas for Sota. I am interested in your experience in comparing an inverted V dipole and an end-fed antenna. I am assuming that the gain and the beam angle would be better for Sota operation with an inverted V than with an end-fed antenna? How much is the difference approximately.

Thank you for your answers Michael, DC8YZ

Hallo Sota Gemeinde,

ich verwende zum Sota Aktivieren einen Inverted V Linked Dipol for 20m und 40m.

Allerginds gibt es bei einigen Summits nicht die Möglichkeit einen Inverted V mit jeweils 10m Schenkellänge und Mittenaufhängung aufzubauen. (gerade im Wald).

Deswegen mache ich mir aktuell Gedanken über endgespeiste Antennen für Sota. Mich interessieren eure Erfahrungswerte im Vergleich zwischen einem Inverted V Dipole und einer endgespeisten Antenne.

Ich gehe davon aus, dass der Gewinn und der Abstrahlwinkel gerade für Sota Betrieb bei einem Inverted V besser wäre wie bei einer endgespeisten Antenne?

Wie hoch ist ungefähr der Unterschied.

Vielen Dank für eure Antworten

Michael, DC8YZ

[MM0FMF]

@DC8YZ

How much is the difference approximately.

Depends on too many variables.

[EA2IF]

I never used a dipole for SOTA activating and I’ve used verticals, endfed sloper, endfed inverted vee and endfed inverted L.
Most of the times I use endfed sloper because it’s much simpler and easy to setup. The results I’ve got with that are fantastic and I really doubt I’d get any better with a dipole. What I’m sure is that carrying a dipole would be heavier and setting up a dipole would be a bit more complex and time consuming than the endfed sloper.
My preference is very clear: endfed sloper.
73,

Guru

[G8CPZ]

Phew! This question has come a lot [on this reflector and elsewhere]. I have both but more often take a EFHW for convenience despite slightly less performance. I’ve written in more detail on EFHW vs linked dipoles here …

Activation Shining Tor G/SP-004 with a Hamstick

This is shaping up to be an interesting thread. Some activators want ultimate Dx, some want to qualify the summit before freezing up. So there’s no one ‘ideal’ antenna solution. This could get like the old myth about the Sixties where you had to be either a Beatles fan or a fan of the Rolling Stones but not both [I was both]. I’ve used linked dipoles [usually in inverted V config] and EFHWs [horizontal or sloper] happily for years but very recently I have also become a fan of my new [Cha MPAS …

Packable 20m or 40m antenna

Hi Ariel, (At my age) I appreciate the benefits of quick deployment for winter activations. I sometimes find my iambic finger and thumb are cold before I even start making contacts. I have the LNR EFT-40/20/10 (12.5m long), LNR EFT-MTR-40/30/20 (19.8m long) and a SOTAbeams 40-30-10 linked dipole with 60m extension added. I use the linked dipole with a 9m pole and - when activating with my smaller backpack – one of the EFHWs with a 4m pole, so my experience isn’t strictly an A vs B comparison. …

End Fed antenna configuration

I have linked dipoles [60/40/30/20 and 20/10/6] and EFHWs [40/30/20 and 40/20/10]. For everyday [i.e. non big event] HF activations, if I’m not using my new Chameleon MPAS Lite vertical, I usually take an EFHW. I do not favour the situation where the wire antenna itself is acting as 1 or 2 of the pole guying ‘cords’. Despite having more benign weather than many parts of the world, the regions I operate mostly from [in north-west England and SW Scotland] often have strong and blustery winds espe…

Antenna Cable for EFHW Antenne / EFHW Antenne Vertical

I use a 10m length of RG174 coax as the feeder for my 60/40/30/20 linked dipole and 40/30/20 EFHW. The attenuation is spec’d at <1dB at 10MHz (30m band). I run a maximum of 10W (CW). Ten metres is long enough for me to sit in a sheltered spot away from the wind whilst the antenna is out in the open. The RG174 coax on a plastic winder weighs 187g and occupies little space in the rucksack.

Just to complicate the story nowadays I mainly take my Chameleon MPAS Lite vertical which performs well on 10MHz-50MHz compared to my EFHWs or linked dipoles [and in A vs B tests, sometimes better - vertical vs horizontal polarization better for a particular radio path?] and has a smaller footprint (good for busy summits) and is quicker to erect and pack away (good for winter weather).

Regarding comparison of weight:

There’s not much difference in rucksack volume between EFHW and linked dipole assuming same length of coax feeder same fibreglass pole (though I often use shorter pole with the EFHW). The vertical takes more rucksack space.

73 Andy

[MM0FMF]

@G8CPZ

Chameleon MPAS

But you aware of its limitations and don’t expect that antenna to perform miracles or to outperform full size antennas. You do expect it to enable you to have plenty of radio fun from a summit. It does that well and has many operational benefits too such as quick deployment etc.

The antenna you have is better than the antenna you don’t have. The corollary of that is the antenna you can deploy on a summit is better than the antenna you cannot deploy.

[G8CPZ]

@MM0FMF

aware of its limitations and don’t expect that antenna to perform miracles

Too true. It’s funny, until recently I was a dyed-in-the-wool horizontal wire antenna kind of guy (You can recognize them!). But reading activation reports where others wrote about the pros and cons of HF verticals, convinced me to hint to my wife about one as a birthday present.

But it’s nice to have choices. Although, more often than not, I take the ‘new toy’ [the MPAS], for a change last month, I took the 60/40/30/20 linked dipole up Nine Standards Rigg [where as I’m sure you know Andy there’s plenty of space and no one else around] and that was good fun.

[K7EEX]

@EA2IF

Most of the times I use endfed sloper because it’s much simpler and easy to setup. The results I’ve got with that are fantastic and I really doubt I’d get any better with a dipole. What I’m sure is that carrying a dipole would be heavier and setting up a dipole would be a bit more complex and time consuming than the endfed sloper.
My preference is very clear: endfed sloper .

I’ll just amplify what was said.

I use both an EFHW cut for 40m (works well also on 20m and 15m without a tuner) or a linked 20/40/60 dipole depending on the summit. Like Guru says, the EFHW is much easier to use and lighter. It is my go-to for longer approaches. That said, the SOTAbeams linked dipole does get better results, mainly because the design gets the ends higher off the ground better than my self-created EFHW implementation.

You can’t go wrong with either, but the EFHW wins out on weight and simplicity.

[DL6GCA]

HAllo Michael

Antenna topics always makes an entertaining thread…

I understand your question more as: which antenna for which conditions.

In general, the question is first to clarify whether an adapted antenna is necessary, or there is an antenna tuner that also adapts a lightning rod as with HB9BIN.

In dense forests (of which some summits consist) I simply push a wire up the telescopic mast and lay it at a branch. A counterweight on the ground is quickly laid out.

In light forests you can also pull up a horizontal wire with a cord that you throw over a branch.

In open areas you can set up antenna areas with your telescopic mast. (As you did at your foto.)

In rocky alpine areas where you don’t like to carry so much, you can also simply hold the wire with your hiking poles.

Think about which antenna(s) to take with you up the mountain when you’re preparing. I recommend just trying it out beforehand.

73 Armin

[VK3ZPF]

I’m a huge fan of link dipoles, I have one that often comes up the easy hills. Portable link dipole | VK3ZPF Ham Radio Blog

For more difficult or longer walks I have recently added a VK3YE inverted L and L match tuner to my kit. Yet another QRP L match antenna coupler - YouTube

I think the inverted vee link dipole works best however the inverted L is smaller and lighter to carry, easier to set up and much easier to change bands.

The inverted L is for QRP while the link dipole is happy at 100 Watts on those hills where travel distance allows the bigger rigs and batteries to be carried.

[AJ6KZ]

I didn’t see a mention of my most recent favorite antenna, and that is a linked EFHW. My current version is a 20/30 but I’ll probably end up adding a section for 40 meters at some point. I have a 92:1 unun (that’s what it turned out to be after I did real world adjustments to the turns on the toroid) at the radio end and it attaches to the radio with a 6" piece of coax. I get about 1:1 SWR on 20 and 30 and I can easily tune in the harmonics of those, but my main goal was to have an antenna for my MTR-3b that didn’t need a tuner.

[G8CPZ]

Warning: Zombie thread alert

Dear Antenna Expert:

I’ve just read “Antenna modeling shows that a resonant half wave wire can be fed at any point (End, Off-Center, Center) without changing gain or efficiency… only impedance”.

EFHW Straight

If true, for the same physical configuration (e.g. wire type, horizontal, sloper, inverted v) an EFHW should have the same gain as a centre-fed HW dipole (CFHWD). No doubt that assumes the RF power is delivered to the antenna with the same efficiency.

My off-centre fed dipole (at home) uses a 4:1 balun, my portable linked dipoles use a 1:1 balun, and my portable EFHWs use a 49:1 UnUn. I’m assuming the efficiency of these impedance matching transformers depends only on their construction and not on their input-output turns ratio.

So that leaves the transmission line: I have to use an ~10m-long coax feeder to reach the balun of my CFHW portable dipoles (e.g. at the top of my 8m pole) but can use a 1m- or 2m-long feeder with my (sloper) EFHW at the ground end (to allow me to sit in a more convenient spot than the end of the wire). Given the greater attenuation (esp. at 28MHz) of the longer feeder, isn’t it always more efficient to use the EFHW than a CFHW?

This conclusion seems to run contrary to what most activators (including me) have written on this reflector, i.e. that CFHWDs have a bit better performance than EFHWs. I wonder if this is purely anecdotal and based on confirmation bias? And has anyone done a true A vs B comparison switching between a CF and EF HWD on the same Rx signals?

In practise, I configure my CFHWDs as inverted v’s where as my EFHWs are slopers. The mid point of the CFs is also the highest where as the mid point of the EFs is a bit lower, and the radiation pattern is probably different. Maybe that has a marginal effect.

In any case, practical considerations sometimes override any marginal performance benefits, e.g. on very ‘lumpy’ summits I find it’s quicker and less hassle to put up an EF (or a vertical) than a CF.

[DD5LP]

Hi Andy,
Something I have on my list to try at some point is a centre-fed V-Dipole (note V - not Inverted-V). The feed-point is in the centre and just above ground level and the two ends are supported off the ground. I already have the PVC angled pipe joining piece that my telescopic fibreglass “Squiddies” fit into to support the V-Dipole along their length - but of course, an alternative would be to use two nearby trees and some cord to hold the ends up.

This design has the advantage similar to an EFHW “sloper” which is that the coax run is short. In the configuration with the two squid-poles, the antenna can also be turned for some small directivity.

At the moment for “light, easy and resonant” - I’m happy with my J-antennas for 20,17,15,12 and 10m but 40m becomes far too large!

73 Ed.

[MM0FMF]

I’d put differences down to efficiency/loss in the match unit for antennas needing them and loss in the coax for coax dipoles. You really need to quantify how good or bad they are so you can compare apples with apples.

I have limited experience with my EFHW compared with centre fed inverted-V dipoles. It’s a hamshop.cz 40/30/20 trapped EFHW. I was never impressed with it in inverted-V or inverted -L sloper but it was very convenient to use on lightweight SOTA activations. Since I found the match unit was “damned hot” after a SSB/CW session on 40m last Summer, I’ve been using an AA5TB inspired match and the antenna can be used on 40/30/20/15/12/10m and seems to work a lot better than before. But… it’s always been deployed as a slopping inverted-L. (817, 2m RG58 to match box, matchbox typically on floor, 4.7m vertical then rest of antenna run out to 1m AGL end stake, 2m counterpoise of wire laying on floor)

So lots of experimenting needed to try an get some real measurements.

[9A3IV]

EFHW Antenna VS Dipole - Field Strength Measured.

Going up with transformation ratio increases losses. More ohms, more capacity, more inductivity

Comparing hf antenas is very hard. It is better to go up in frequency. Compare 6m, even better 2m antenas in different configurations. Meters or yards are relative measure. Apsolute measure is lambda.

[WA7MWF]

Dipoles are great but the ideal design requires symmetry. That can be difficult to achieve in the field with a lightweight rig. Of course EFHW antennas don’t require symmetry. Dipoles tend to require more and stronger supports than EFHW wires. Wire antennas work best with increased height and are preferably oriented to put the maximum directivity in a favorable direction—which all are a bit easier with an EFHW. Lightweight coax tends to be lossy, and dipoles tend to require much longer coax runs than EFHW antennas.

I think those factors favor EFHW antennas for field use. A bit of loss in the impedance transformer seems a small price to pay.

[DL1CR]

@WA7MWF

A bit of loss in the impedance transformer seems a small price to pay.

With a typical 1:49 transformer, the losses are around 1-2db and practically completely negligible.

73 Chris

[MM0FMF]

@WA7MWF

EFHW antennas don’t require symmetry.

Really? Don’t confuse the physical deployment of the element(s) with how those element(s) are fed. i.e. at the centre and so low impedance vs the end and thus high impedance.

[IK6BAK]

Virtually any antenna is ok when you are an activator.
Linking the RTX to an animal fence also brings home several QSOs, just happened.
The goodness of an antenna is measured in S2S when we are forced to compete with fixed stations.
Currently, before leaving for an activation, I check if there is something on the top to lay a very light OCF dipole.
Where the top is completely devoid of trees, crosses or anything else, I use a proxel pro-x2 stretched to 3 meters and with a couple of random counterpoise wires, easy and very quick to install.
These are the actual configurations, but things can change day by day
In any case no feeling with EFHW.

[ZL4NVW]

I’d expect an EFHW to require the same symmetry as a dipole. The standing wave on both should be identical, after all.

And experience on tricky summits seems to back this up. The following deployments seemed to work very poorly:

• EFHW supported at 1/4 point (well, duh)
• EFHW with inverted V off-vertical (why is this so poor?)
• EFHW with one horizontal half and one steep sloping half (more like a centre-supported inverted L)

All tried in desperation on tight or steeply sloping summits. And all ‘successful’ in that they qualified the summit, all be it with difficulty.

In the latter case (activating on a steep \ face) I now prefer a sloper, mast at top end, and us a long guy rope tied to the top end of the antenna and back to the ground on the far side of the mast to support the mast.

[G4OBK]

@IK6BAK

Virtually any antenna is ok when you are an activator.

Yes, I agree Eliseo but some pieces of wire are better than others!

The half wave end fed - I was a doubter, even a non-believer you may say, in the popular half wave end fed.

On 100s of HF SOTA activations since I started from the hills and mountains in 2005 I have always used the half wave resonant link dipole without baluns, configured as an inverted vee. I have used an inverted L on top band a few times on summits, but not in the last ten years.

Despite working 1000s of SOTA activations mainly in Europe, and UK but also worldwide (I have over 200,000 Chaser points) at very good signal strengths, I was still dubious UNTIL LAST WEDNESDAY when I tried the half wave end fed out on an activation myself.

The reason I wanted to try out the half wave end fed was because I am undertaking a solo trip to the DM/RP DM/HE and LX region in May. Without a fellow operator with me (of late this is usually @GI4ONL) I was worried that if my KX3 lets me down or my link dipole breaks beyond an easy repair, I will have substitutes by way of my YouKIts HB-1B and a half wave end fed antenna.

So a few weeks ago I sourced a 49:1 balun rated at 50 watts made by G4ICD (www.rfcomms.co.uk). This was secondhand on eBay and cost £15. Its quite well made - the internal components are potted and the connecter is a good quality N type. The radiating wire fits into a spring connection and I have a strainer fitted which can be pegged into the ground or be left floating a foot or two above ground in mid-air. I resonated a 67 feet length of wire in my garden for optimum SWR around 7050 KHz and shortened this slightly to get the resonance as good as I could on that frequency. The SWR on 20m,15m and 10m was well under 2:1 over a wide bandwidth on all three bands. On 30m as expected, the SWR was around 8:1. I fitted a link at an appropriate point for 30m operation. This is easy to reach from ground level when the HWEF is mounted on a 5m pole. I also found that with the 30m link open the SWR on 18 MHz was a very usable 1.5 - 2:1. I used no counterpoise, just a 6m length of RG-58CU coaxial cable to the radio. (I use thinner RG-178 on my resonant dipole). The antenna is resonant on six bands therefore without needing an ATU.

On Wednesday I headed up G/TW-002 - one of the nearest summits to where I live, and my favourite out of the three TW summits in the Cleveland Hills which I visit every year.

Here are a few photos of the antenna and parts of it on the summit. I configured this as an inverted L fed at ground level, no counterpoise, just reliance on the 6m length of coax braid in the feedline. I tied off the far end to a stunted tree on the moor at a height of around 1m above ground.

Despite my doubts about the half wave end fed, I have to admit I was pleasantly surprised. I wasn’t using my Elecraft KX3 running 10 watts with it’s superb receiver and filtering. Instead I used an inferior 10 year old Chinese made YouKits HB-1B running 4-5 watts depending on the band used. I operated on 40/30/20 metres for a period of 45 minutes and made 37 CW contacts, all were with EU and included 5 S2S QSOs with stations who called me (Thank you @HB9BIN, @F/DL6GCA/P, @IK2LEY, @HB9CEV, @HB9BQU).

1119z-1134z 40m 18 Qs
1138z-1146z 30m 6 Qs
1148z-1204z 20m 13 Qs

I didn’t try the half wave EF on any other bands.

So am I a convert to the half wave end fed? I would say not yet, but it’s a great tool to have in the cupboard and I will definately be using it again!

Point of note - an aside to the thread - I did not work @OE6GND during this activation. Although he did claim a chaser QSO. Gerhard clearly couldn’t hear me. He called over the top of Art @HB9CEV/P twice when I was in S2S QSO. I called him out in my response to Art sending “SRI ART QRM FM OE6GND” unfortunately Gerhard took this to mean he had a QSO and wished me 73. Reports were not exchanged and the QSO was not logged. If Gerhard had called me later, correctly, I would have been happy to work him, but he didn’t.

73 Phil G4OBK