Efficiency Comparison between Transformer Cores with 14/2 and 24/3 winding ratios

 Measurements of the efficiency of the transformer cores have been made using the NanoVNA H4.

The results are documented here:

https://www.dropbox.com/sh/y4mb9xnwbn70hll/AACghPO0l2TF4UOuJAwyAGv6a?dl=0

The NY4GEFHW Store is live! ny4gefhw.com

 The URL is ny4gefhw.com

Please take a tour and browse around.

Trapped End Fed Half Wave - What is the Price of Convenience?

The thirty meter band is such a "money band" for SOTA activations that it simply can't be ignored.  Traditional end fed half waves either ignore it or put in a link to enable that band - e.g. the EndFedZ MountainTopper by LNR Precision (now Vibroplex). 

It is possible to configure an end fed wire with two traps, one for 20m and the other for 30m.  When finished, the inductive loading of the two traps shortens the antenna from 66 feet to 58 feet.   The bandwidth for 20m covers the entire band.  The band width for 40m is reduced but still perfectly acceptable within the CW portion of the band.  There are losses associated with this trap - the combined losses from both traps is somewhere between 0.3 and 0.7 dB.

I used it during my activation of Grassy Ridge Bald W4C/EM-001 as documented by this YouTube video and it worked fantastically well with my LNR MTR4Bv2 and GM0EUL paddle.

Here is an image of the end fed half wave antenna.  Only one trap is visible.

 

Is it worthwhile to use an RG8X Feedline for SOTA?

 I was just going through reflection loss calculations and comparing efficient and inefficient transformers.

On 60m, inefficient transformer are only 58% efficient.  Even with low SWR - say 1.5:1, the full entitlement available radiated power is only 2.78 watts.  

Compare that with an efficient transformer at 83% efficiency - radiating into an SWR of 6 but matched with an ATU, the radiated power is 3.77 watts.   Full entitlement with no coax losses is 4.15.  one would not want to go through this exercise with an RG174 feedline as the coax losses are worse - available output down to about 2.3 watts.  With very low SWR say 1.2, you are almost at full entitlement even with RG174.

So the lesson learned is - have a resonant antenna, however, in the case of mismatched antenna use the RG8X feedline instead of the RG174 and it always beats the inefficient transformer.

Having said all that, all this efficiency talk can be dominated by antenna configuration for an intended purpose.  Let's say the intended purpose is to work close in chasers on 60m.  An inverted V with an Apex at 20 feet has close to a 4 dBi  at a high take-off angle as opposed to the same end fed wire set up as a vertical (as impractical as that may seem).  The vertical will have a null at the high takeoff angle.  So an efficient transformer even with low SWR will not work any stations and that inefficient transformer will work those close in stations all day long.   There are a lot of factors that have to be optimized for effective antennas and as always - it always pays to begin with the end in mind and work backwards.  What is the purpose, configure the antenna for that purpose and optimal gain, and then worry about SWR second and last transformer efficiency.  It isn't easy.  As often, summit conditions dictate antenna configuration - presence or non-presence of supports and it becomes a "one size fits all" or "one antenna configuration fits all" proposition - the ubiquitous inverted V.

 The "SOTA Package" antenna includes 30m and 60m.   

Base antenna is a 40m half wave with a powerpole connector at the end for any extensions desired.

Options still include link for 17m, 30m, 60m extension, 80m extension 

Gen 3 of the NY4G End Fed Half Wave (Ariel's Aerials)

 

I have added both the 60m and 80m extensions to the system

The 60 meter extension is particularly suited to the narrow allocation on 60m between 5.3 MHz and 5.4 MHz.  The SWR is at or below 1.5:1 for the entire 60m allocation.  See the image below:

Weight of the entire antenna is 316g with the 60m extension - or only 53g heavier than the base antenna with 40-6m coverage.

Testing of the antenna using the Reverse Beacon Network on December 26, 2020 showed that the second harmonic of the 40m half wave has a better signal than the third harmonic of the 80 half wave as seen on the 20m RBN hits at 1527 UTC on 14.061 MHz (third harmonic) versus the ones at a later time on14.065 and 14.067 MHz (second harmonic).  RBN S/N ratio on both the 60m and 80m extensions were quite good and comparable to the 20m S/N ratio.  One can easily be heard on the 60m and 80m extensions.

The band width on 80m is quite narrow - with the 2:1 SWR band width being about 100 kHz wide and the extension must be carefully tuned for the rig to be employed.   If you are a recent buyer of the LNR MTR4Bv2 or the YouKits 7 Band 2020 version (https://www.youkits.com/products/youkits-hb-1b-mk5-2020-4-band-qrp-cw-transceiver-fully-assembled-and-tested), these extensions would be perfect.

Contrast the above image with the full size 135 foot EFHW Inverted L shown by the image below - shows that the shortening of the antenna has reduced the bandwidth by a factor of 3.  The KX3 being my shack radio has no problem tuning the antenna in the upper portion of 75m in the phone portion

Gen2 of the NY4G End Fed Half Wave

 

Generation 2 with the following improvements:

Winder is separable from the transformer so it can be replaced if damaged or if one that is impervious to weather is desired, a plastic one may be substituted

The end caps are now made of aluminum instead if walnut.   This gives more ruggedness to these parts.

Picture shown below is during testing and pruning for best balance across the bands.

Walnut winder and transformer box

88 feet of wire in the air for 60m operation.  The 60m extension is separable so that the 40-20-15-10-6 can also be deployed - resonant on these five bands

Walnut transformer box and white UHMW winder

Pruning and VSWR scans - the following are typical from the bottom end of each band

to the top portion of the band

The 60m extension connected

Antenna for SOTA, POTA, and DXpeditions

Initial Prototype:  The initial prototype had a turns ratio of 14:2 (14 secondary and 2 primary).  It used a single 100 pF capacitor across the center conductor to ground.  The tests of this initial prototype after pruning for a best compromise resulted in:

2:1 SWR Bandwidth on 40 meters is 6.730 -> 7.530 MHz with a dip to 1.3:1 SWR at 7.060 MHz

2:1 SWR Bandwidth on 20 meters is 13.910 -> 14.806 MHz with a dip to 1:1 SWR at 14.360 MHz

2:1 SWR Bandwidth on 15 meters is 21.010 -> 22.070 MHz with a dip to 1.6:1 SWR at 21.610 MHz

2:1 SWR Bandwidth on 10 meters is 29.1 -> 30.8 MHz with a dip to 1.8:1 SWR at 29.900 MHz

On 10m it is not very usable unless one has an ATU.

The second prototype (photo below) used two 220 pF capacitors in series which technically by the numbers should be 110 pF.  My measurements of the capacitance was closer to 130 - 140 pF.  This had a substantial effect on making 10 meters usable without a tuner.   The results are as follows:

2:1 SWR Bandwidth on 40 meters is 6.820 -> 7.510 MHz with a dip to 1.3:1 SWR at 7.150 MHz

2:1 SWR Bandwidth on 20 meters is 13.990 -> 14.840 MHz with a dip to 1:1 SWR at 14.430 MHz

2:1 SWR Bandwidth on 15 meters is 20.950 -> 22.270 MHz with a dip to 1.1:1 SWR at 21.650 MHz

2:1 SWR Bandwidth on 10 meters is 29.1 -> 30.8 MHz with a dip to 1.3:1 SWR at 29.900 MHz

Being a link dipole for 30m - here are the results for 30m:

2:1 SWR Bandwidth on 30 meters is 9.730 -> 10.880 MHz with a dip to 1.0:1 SWR at 10.280 MHz with a SWR between 1.3 and 1.2:1 from 10.100 to 10.150 MHz

A third prototype had the following results (identical in construction to the second one) with the following results.

2:1 SWR Bandwidth on 40 meters is 6.820 -> 7.500 MHz with a dip to 1.3:1 SWR at 7.150 MHz

2:1 SWR Bandwidth on 20 meters is 13.980 -> 14.850 MHz with a dip to 1:1 SWR at 14.440 MHz

2:1 SWR Bandwidth on 15 meters is 20.780 -> 22.280 MHz with a dip to 1.2:1 SWR at 21.600 MHz

2:1 SWR Bandwidth on 10 meters is 24.5 -> 29.9 MHz (which actually overlaps into 12 meters) with a dip to 1.1:1 SWR which is wide - 28.0 to 28.5 MHz so 10 meters is now perfectly usable without a tuner and so is 12m which is a very narrow band.

This is one heck of an antenna - requiring no tuner on 40m, 20m, 15m, 12m and 10m and power handling ability as follows SSB 60w, CW - 40w and Digital (key down) - 30w.

The final product:

 

 

All Time New One (ATNO) #315. South Orkney Islands

This DXpedition took place between late February and early March 2020 just before the pandemic hit with full force.  Because of the pandemic, the major DXpeditions have been cancelled.  The one going to Midway was one I was looking forward to but became victim to the pandemic.   The last major one I was able to work was VP8PJ and I was able to make contact on 30m CW.  Between the sunspot minimum and the effects of the pandemic - I will likely be stuck on #315 for a long while.

My latest activation videos

My new backpacking set-up for SOTA Activations

 For backpacking where minimalism is important to me, my go to radio is the LNR MTR3B Mountain Topper.   The radio itself weighs 174 grams.  WG0AT has repackaged his into a clear lid tin that only weighs 120g.   With the battery and the key made GM0EUL, the whole set up weighs less than a pound.

I used a small camera case which has the earbud.

For an antenna, I use a 40-30-20 link dipole.  There is a separable link for 30m.  Separating this link makes it an EFHW on 30m.  With the link connected - it is a full wave on 20m and a half wave on 40m.  The winder is a home made UHMW PE plastic.  The line is spearfishing line and the wire is from SOTABeams.  The weight includes the weight of the line thrower.   

The entire set-up including antenna, radio, etc weighs about 1.5 pounds including the waterproof dry bag from Sea-to-Summit.

Worked a new ATNO #314 - 4U1UN - Remotely from a Hospital - 5 Watts QRP

My  Dad had a stroke and so I was doing duty in the hospital (Saint Francis Downtown) and 4U1UN had been on the air.   I have the ability to remotely control my home station via my phone.  I was first alerted that 4U1UN was on the air on 40m CW by HamAlert and my phone by Morse indicated it was an RBN spot.  I quickly dialed into my home station via the browser on my phone.  I listened to 4U1UN work European stations for about an hour or so.  He was calling CQ with the EU at the end of the CQ string.   My finger was ready to pounce on the call button the whole time waiting for the CQ string to stop sending EU at the end.  I had the split frequency all ready to go on the TX.  I was going to transmit exactly 1 kiloHertz up from his TX frequency.AT 2358 UTC on December 8, 2019, he stopped sending the EU string at the end of the CQ.  He was still loud - a solid 599.  Then I pounced - NY4G.  He replied back NY4G 599.  I replied TU 599.  It took about 3 calls and I was in the log.  I later confirmed it through his online log several days later.  It was later confirmed in LOTW for #313.  (Actually #314 but Revillagigedo never confirmed via Card or LOTW despite being confirmed in his online log)

New Book on Summits On the Air Activating

Now available on Amazon:

The 100 Unique Summit Challenge - eBook

The 100 Unique Summits Challenge - Paperback

101 Summit Activations Completed

My blog posts to document the march up to the 1000 point goal is woefully out of date.   If you want to see the detailed blow by blow for every activation - you will have to purchase my book due to be out in October 2019. 

I finally got my Mountain Goat designation after my 97th summit activation of Mount Sterling on July 16, 2019.

In the process i was able to establish the following:

Fastest ever to Mountain Goat (1000+ points) in North America.   The previous mark was held by NA6MG which was over a period of 9.8 months.  The mark I set was 8.9 months.

I was also the 6th fastest to MG ever in the SOTA record books

In terms of number of summits to achieve Mountain Goat - I was able to be among the top 5 fewest summits to achieve it and the only person to have 100 summits or less in less than a year.

Head to Head Test - Center Fed Link Dipole Versus EFHW on 20m

The jury is in.   The same QTH, the same time, the same configuration (inverted Vee), same height above ground at the apex.    There is no significant edge for the link dipole in performance.   The EFHW wins on convenience, ease of deployment, weight (EFHW 160 grams, Link Dipole is 200 grams).

Link Dipole is a Home Brew

EFHW is an LNR 40-20-10

Power : 200 mW

Mode: WSPR