Early last week, Paul (K7CW) sent me a link to an interesting video showing the Duga antenna system. The term was not familiar to me but when I went to the site I immediately recalled the significance of what I was seeing!



Those of you that have been hams for a long time will no doubt recall the Russian 'Woodpecker'. The 'Woodpecker' was a strong, fast repeating signal / racket that often wiped out amateur communications on 20m here in North America ... maybe other parts of the world as well.

Amateurs with yagis eventually determined that the signals (yes there was more than one it seemed) were coming from the USSR. The QRM was persistent and in spite of formal complaints being lodged via diplomatic channels, continued for many years ... from 1978- 1989. Some of the new transceivers built during the time actually had a 'WOODPECKER' position on the noise blanker switch, hopefully offering some relief to the problem.

For you younger folks, here's what Duga usually sounded like:


Several web searches brought up numerous descriptions of the Duga (Russian for 'arc' or 'bow') project, some with conflicting information. From what I can sort out, there were three Duga sites ... one near Chernobyl, another near Chernihiv and a third, much later, in Siberia. The first two (Duga and Duga-1) were in the Soviet Ukrainian SSR (now Ukraine) while the third was located near Komsolmosk-on-Amur in the Russian far east. One source indicates that the second Chernobyl site is often misidentified as the Duga-3 array and should be referred to as Duga-1, with Duga-2 being the Siberian location.

Initial speculation suggested this intrusive signal was some form of 'jammer' ... very common during the Cold War. It wasn't long before the true nature of Duga was thought more likely to be an 'over-the-horizon' (OTH) long-range radar system for detecting the launch of North American missiles aimed at the USSR. The three radar sites gave the Soviets good over-the-pole coverage as well as to the east, where it could also be utilized for tracking domestic rocket launches.

courtesy: http://www.globalsecurity.org/wmd/world/russia/steel-yard.htm

The antennas themselves appear to be phased dipole curtain arrays, commonly used in various configurations by shortwave HF broadcasters.

courtesy: http://www.antenna.be/hr.html

These antennas featured an array of phased dipoles in front of a screen curtain 'reflector', often made of rows of wide-spaced wires. One source indicates that the Duga arrays developed ~30db gain over a standard half-wave dipole ... an enormous task on these HF frequencies. One system had a '4/4/1' configuration meaning each bay consisted of a dipole array 4 wide and 4 high. Another source spoke of  a system that was 32 high and 16 wide in total. Whatever the numbers, these free-standing structures were gigantic and true marvels of engineering. The large Chernobyl array is 150m high and 500m wide, with an estimated weight of ~ 14,000 tons.

Each site was paired with a receiving array ... remember, this was a radar system, with two of the three systems having the receiving array located tens of kilometers from the transmitter. The Chernobyl Duga is said to have had the receiving antenna located on site. Sources discussing physical size indicate the dimensions for the receiving array to be larger than those of the transmitting antenna. It seems possible then, that the pictures and videos commonly found are those of the receiving array and not of the transmitting antenna. It might make sense to have more gain on 'receive' than on 'transmit' as echoes from small targets many thousands of miles away would not be easy to detect. No matter what the actual case, I can only imagine the fun of hooking up an HF transceiver to one of these arrays during a DX contest on 20m CW!

The Chernobyl site shows two arrays, side-by-side ... possibly the larger being that used for receiving and the smaller one for transmitting. This antenna has been noted as a 30/10/2 array ... 2 bays, 30 dipoles wide and 10 high, 600 elements in all!

Further research tends to indicate that each dipole is what is called a 'Nadanenko' dipole. The main feature of this style was its cage-styled construction, giving the element a large diameter resulting in a broad bandwidth.

courtesy: https://shema.info/en/antenna/

Each dipole was fed at the center with open-wire ladder line and some pictures show obvious signs of open wire phasing lines, no doubt used to electrically steer the array over its reported 30 degree directional pattern.

courtesy: englishrussia.com

After watching the video, Paul (K7CW) made some interesting observations, some of which may be seen in the above photograph. His eyes must also be a lot better than mine as he managed to correctly count the number of dipoles in the array!

First, you see that there are two sets of arrays 15 driven elements wide by 10 driven elements high for a total of 600 elements! They are intermeshed and offset from each other by 1/2 wavelength both vertically and horizontally. There is a horizontal wire screen reflector behind the driven elements.

Some of the other things I noticed are ...

... you can see the open-wire feeds and reflector screen. Each set of collinear elements is fed individually with open wire line. There is a support line between each two bays of driven elements.

... that the reflector screen is supported on the sides by the stand-alone free-standing towers at each side of the array. (I had been wondering why they would have those towers next to the array like that. Now I know.)

... that the element supports are steel pipe instead of fiberglass (or something similar). Apparently, the shape of the radiators allows for the pipe supports to enter the element cages at the element low-impedance point which made the supports invisible to the antenna and also allowed for the supports to not radiate themselves.

courtesy: http://anzee.livejournal.com/65530.html

There are a number of YouTube videos showing various adventure-seekers climbing the Duga array near Chernobyl. The videos give you a better idea of its sheer mass as well as a closer look at the dipole structures themselves.



The Duga system was operative between 7 and 19MHz, with 40kHz wide pulses, usually lasting for about seven minutes. The most common pulse rate was at ~10Hz but this sometimes varied. Power levels used often mention 10 megawatts but it's not clear if this was RF output, peak pulse power or ERP.

It's somewhat gratifying after all these years, to actually see close-up, where the Woodpecker signal started its journey around the world and to appreciate the superb engineering that went into these impressive structures ... but sad to see the last one in such a rusted state of decay and abandonment. It would be nice to hear it just one more time ... but please, only for a couple of minutes.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

For the 2016 Colorado 14er Event, I had to choose really easy SOTA summits to activate because I had fractured my ankle earlier in the summer. At this point, I was able to hobble around with a protective boot but walking more than a few hundred feet was difficult. On Saturday, we drove up Pikes Peak and took a short stroll away from the vehicle to operate. On Sunday, we decided to activate Monarch Ridge South (W0C/SP-058), using the sight-seeing tram that goes to the top.

Access is right off Monarch Pass (Hwy 50), where there is a large parking lot. There is a trail that goes to the top and we’ll be back to hike that some other time. (Actually, Joyce K0JJW and I already tried to snowshoe to the top in blizzard conditions but that is another story for another day.) The trail is a popular mountain bike route, so we saw lots of bikers in the parking lot unloading gear. Monarch Pass is oriented north/south and the trail heads off to the east (behind the tram building).

The tram boarding location is inside this building at the bottom of the tram. We purchased tickets in the nearby gift shop, which is worth a look if you need a map, book, ice cream cone or trinkets. See their website for latest schedule and pricing.

 

 

 

Here’s a photo of the tram going up the side of the mountain. Of course, the views are great and the ride takes about 10 minutes. The tram car holds four people and a reasonable amount of SOTA gear.

 

 

 

At the top, Denny KB9DPF made contacts on 2m FM, aided by expert logger Kathy KB9GVC. The actual summit is a ways to the south of the tram, maybe a tenth of a mile, but we operated from a concrete pad on the north side. The ridge is flat and we judged the activation area to be very large.

We made a total of 13 contacts on 2m and 70cm, including 5 other SOTA summits (S2S).

 

 

I used my Yaesu FT-817 on 432.100 MHz SSB, hoping to find someone in the UHF contest that is happening concurrently with the 14er event. I didn’t work anyone on 70cm SSB but I did work K3ILC in Colorado Springs on FM at a distance of ~90 miles. Not too bad. The Arrow antenna is attached to my hiking stick via the camera mount thread.

 

 

 

There is a substantial radio site on Monarch Ridge that did provide some RF interference to us on 2 meters. The 70 cm band seemed to be unaffected but I can’t be sure. The “bad boy” transmitter is the KMYP automated weather station (AWOS) transmitting continuously on 124.175 MHz. Well, at least we could receive current weather information. We did relocate to put some distance between us and the transmitters but my lack of mobility kept us from going too far.

If you are looking for an easy access SOTA summit near Monarch Pass with excellent views, this is it. The hike up should not be very difficult but the tram makes it even easier. If you plan to operate 2 meters, expect some interference. Next time, I’ll try locating even further away from the transmitter site. I might even bring along some bandpass filters. Other SOTA enthusiasts have reported no problems on the HF bands.

At the time of this post, there are plans to put a 2m amateur repeater at this site on 145.325 MHz.

73, Bob K0NR

The post Monarch Ridge South SOTA Activation (W0C/SP-058) appeared first on The KØNR Radio Site.

Bob Witte, KØNR, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. Contact him at [email protected].

On Sunday, 7 August 2016 I completed my 9th SOTA activation.  Which I realize doesn’t sound like very many considering I completed my very first SOTA activation in November of 2011.  Between November 2011 and November 2012 I added seven more to the list.   Then I got sick, got busy, had some personal issues and before I knew it the summer of 2016 was quickly slipping away.

For those who have followed my other blog and my podcast (Practical Amateur Radio Podcast), you are aware I started exercising and eating better to get in better shape and lose weight.  While I’ve taken over 10 million steps, walked just short of 5,000 miles and climbed 22,000 floors since I started wearing my Fitbit in the summer of 2013, today was the first SOTA activation I had attempted since losing over 50 pounds.   While I’m presently in a weight holding pattern, I still make every effort to complete 10,000 steps per day.  This walking has kept me in pretty good shape considering where I was just a few years ago.   Best I can remember, it took me over 2 hours to hike to the summit of Chief Mountain in 2013.

The trailhead of Chief Mountain is about 40 minute drive from my QTH.  As Chief Mountain is extremely popular with hikers/peak baggers I wanted to get an early start.  I arrived at the trailhead just after 6:30 AM.  With my boots tightly laced and my pack strapped to my back, I hit the trail at 6:45 AM.

The above trail sign is approx. 1 mile from the trailhead parking area and 2 miles below the summit.

One hour and five minutes later I’m standing on the summit of Chief Mountain.  The total trail length is approx. 3 miles with a total elevation gain of just under 1,000.  This is a great hike and I highly recommend it.

My SOTA HF setup hasn’t changed since 2012.  If it works, why mess with it?  I use a Buddipole vertical setup with a single wire counterpoise.  For this activation I setup for the 20 meter band.  I pack enough hardware to create a full-size 1/4 wave length vertical (no coil) along with a 1/4 wave length elevated counterpoise.   With band conditions being less than desirable, I believe the extra weight of the two aluminum arms (versus the coil) was worth the effort.

My Buddipole vertical setup with my SOTA flag flying proudly.

Of course, my Elecraft Kx3 (serial number 057) running 10 watts  is still very much my pride and joy of my QRP setup and I power it all with my 4+ year old Buddipole A123 Nanophosphate Battery Pack (13.2v, 9.2Ah).   However, I must admit I was a little worried if my A123 battery pack would still work after all this time.  But I would not be disappointed.  They performed just as expected.

HF Contacts (20m SSB)

In just a little over 45 minutes I worked 24 stations from across the US and Canada.   Many stations were familiar from previous activations along with many new ones.  New Hampshire was the furthest QSO made during this activation.

Thanks to W0MOS, AD1C, N1CC, N1KB, NE4TN, KG3W, K7ZO, VE2JCW, WG0AT, W9MRH, KI4SVM, K2JB, N9FZV, W0MNA, NS7P, VA6FUN, K3SAE, W9RCJ, KK6GMN, KB5IMK, WA9BNZ, N1RCQ, KX3DX, KD0HRM.

A quick “selfie” from my operating position.

VHF Contacts (2m FM)

I don’t always pack along the Elk 2m/440 5 element log-periodic antenna.  But as this was the 25th Annual Colorado 14er and SOTA weekend, I wanted a chance to make as many summit to summit (S2S) QSO’s as possible.  Again, the added weight paid off.  I made an additional six VHF QSO’s with four of those being S2S QSO’s.

Thanks to KD0WHB, WB9KPT, N0BCB, KK6JQV, KC1EPN

Summit to Summit (S2S)

As an activator, we often have the opportunity to work other mountaintop stations in what are known as Summit to Summit (S2S) QSO’s.  As this was the 25th annual Colorado 14er and SOTA weekend, I knew my chances of working several Colorado mountain top stations would be good.  During the 90 minutes I spent on Chief Mountain I managed to work eight stations on seven different mountain tops.  Including two stations out of state (California and Oregon).

All-in-all this was very much a successful SOTA activation.  While the HF band conditions were not perfect, the time spent on the air from almost 12,000 ASL was certainly worth it.  Anytime I take amateur radio outdoors it always ends up being about the experience and not about anything else.  Just the way it should be….

Until next time…

73 de KDØBIK (Jerry)

Jerry Taylor, KD0BIK, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. He is the host of the Practical Amateur Radio Podcast. Contact him at [email protected].

On Sunday, 7 August 2016 I completed my 9th SOTA activation.  Which I realize doesn’t sound like very many considering I completed my very first SOTA activation in November of 2011.  Between November 2011 and November 2012 I added seven more to the list.   Then I got sick, got busy, had some personal issues and before I knew it the summer of 2016 was quickly slipping away.

For those who have followed my other blog and my podcast (Practical Amateur Radio Podcast), you are aware I started exercising and eating better to get in better shape and lose weight.  While I’ve taken over 10 million steps, walked just short of 5,000 miles and climbed 22,000 floors since I started wearing my Fitbit in the summer of 2013, today was the first SOTA activation I had attempted since losing over 50 pounds.   While I’m presently in a weight holding pattern, I still make every effort to complete 10,000 steps per day.  This walking has kept me in pretty good shape considering where I was just a few years ago.   Best I can remember, it took me over 2 hours to hike to the summit of Chief Mountain in 2013.

The trailhead of Chief Mountain is about 40 minute drive from my QTH.  As Chief Mountain is extremely popular with hikers/peak baggers I wanted to get an early start.  I arrived at the trailhead just after 6:30 AM.  With my boots tightly laced and my pack strapped to my back, I hit the trail at 6:45 AM.

The above trail sign is approx. 1 mile from the trailhead parking area and 2 miles below the summit.

One hour and five minutes later I’m standing on the summit of Chief Mountain.  The total trail length is approx. 3 miles with a total elevation gain of just under 1,000.  This is a great hike and I highly recommend it.

My SOTA HF setup hasn’t changed since 2012.  If it works, why mess with it?  I use a Buddipole vertical setup with a single wire counterpoise.  For this activation I setup for the 20 meter band.  I pack enough hardware to create a full-size 1/4 wave length vertical (no coil) along with a 1/4 wave length elevated counterpoise.   With band conditions being less than desirable, I believe the extra weight of the two aluminum arms (versus the coil) was worth the effort.

My Buddipole vertical setup with my SOTA flag flying proudly.

Of course, my Elecraft Kx3 (serial number 057) running 10 watts  is still very much my pride and joy of my QRP setup and I power it all with my 4+ year old Buddipole A123 Nanophosphate Battery Pack (13.2v, 9.2Ah).   However, I must admit I was a little worried if my A123 battery pack would still work after all this time.  But I would not be disappointed.  They performed just as expected.

HF Contacts (20m SSB)

In just a little over 45 minutes I worked 24 stations from across the US and Canada.   Many stations were familiar from previous activations along with many new ones.  New Hampshire was the furthest QSO made during this activation.

Thanks to W0MOS, AD1C, N1CC, N1KB, NE4TN, KG3W, K7ZO, VE2JCW, WG0AT, W9MRH, KI4SVM, K2JB, N9FZV, W0MNA, NS7P, VA6FUN, K3SAE, W9RCJ, KK6GMN, KB5IMK, WA9BNZ, N1RCQ, KX3DX, KD0HRM.

A quick “selfie” from my operating position.

VHF Contacts (2m FM)

I don’t always pack along the Elk 2m/440 5 element log-periodic antenna.  But as this was the 25th Annual Colorado 14er and SOTA weekend, I wanted a chance to make as many summit to summit (S2S) QSO’s as possible.  Again, the added weight paid off.  I made an additional six VHF QSO’s with four of those being S2S QSO’s.

Thanks to KD0WHB, WB9KPT, N0BCB, KK6JQV, KC1EPN

Summit to Summit (S2S)

As an activator, we often have the opportunity to work other mountaintop stations in what are known as Summit to Summit (S2S) QSO’s.  As this was the 25th annual Colorado 14er and SOTA weekend, I knew my chances of working several Colorado mountain top stations would be good.  During the 90 minutes I spent on Chief Mountain I managed to work eight stations on seven different mountain tops.  Including two stations out of state (California and Oregon).

All-in-all this was very much a successful SOTA activation.  While the HF band conditions were not perfect, the time spent on the air from almost 12,000 ASL was certainly worth it.  Anytime I take amateur radio outdoors it always ends up being about the experience and not about anything else.  Just the way it should be….

Until next time…

73 de KDØBIK (Jerry)

Jerry Taylor, KD0BIK, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. He is the host of the Practical Amateur Radio Podcast. Contact him at [email protected].

PSK reporter

Over the weekend I tried some JT-65 HF again after getting great feedback from my last blog post, I was under the impression I had some JT-65HF hits and in fact it turns out I netted ZERO contacts. The reports I was seeing on PSK reporter were stations I was hearing and  not hearing me! One of those who commented advised me to listen to the signal WSJT-X was sending. It turns out that was one of my problems, the software was not sending out CQ but a solid tuning tone. Seems this was a software issue with WSJT-X if I was to use the "tune" button on the software to see my ALC it would then send the same tone when TX was enabled. The way around this was to just restart WSJT-X and don't use the tune button on the software. There is a bata test software out now version 1.7 and I may download and try it. My results have been much better once this error was corrected.

Ham spots report

Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

PSK reporter

Over the weekend I tried some JT-65 HF again after getting great feedback from my last blog post, I was under the impression I had some JT-65HF hits and in fact it turns out I netted ZERO contacts. The reports I was seeing on PSK reporter were stations I was hearing and  not hearing me! One of those who commented advised me to listen to the signal WSJT-X was sending. It turns out that was one of my problems, the software was not sending out CQ but a solid tuning tone. Seems this was a software issue with WSJT-X if I was to use the "tune" button on the software to see my ALC it would then send the same tone when TX was enabled. The way around this was to just restart WSJT-X and don't use the tune button on the software. There is a bata test software out now version 1.7 and I may download and try it. My results have been much better once this error was corrected.

Ham spots report

Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

We’ve drawn the 36 winners of our 50+ NooElec SDR receivers. We had 1,398 entries from ham radio operators all over the world.

I’m always amazed how ham radio brings those with diverse backgrounds and geography together with a shared hobby and passionate interest — sometimes I think the world could take a lesson from us! I’ve made so many radio friends from all corners of the globe.

Before I announce the winners, I want to thank NooElec, our contributors, our sponsors and all of our loyal readers who have supported us over the years. We have over 4,500 newsletter readers and nearly 15,000 followers on social media and I’m grateful for every single one!

So… without further delay, here are the winners:

Two (2)
NESDR SMArt HF Bundles

Ray SM5XLP
Chris KD7DBL

One (1)
Raspberry Pi 3 NESDR SMArt Bundle
Includes Raspberry Pi 3, enclosure, SD card, and
2-pack of NESDR SMArt sets with antennas

James KI4HTC

Three (3)
NESDR SMArt sets with antennas
2-pack

Stefano IUØDFT
Dan W0UHF
Daryl N1BGR

Ten (10)
NESDR SMArt SDRs
2-pack

Sandeep VU3GUD
Mike VE3MIC
Roger G6NTQ
Robert KA1VF
Cori 2E0HWG
Bob W2RWM
Jari OH2BU
Rob W8MRL
Richard 4Z4DR
Pierre HB9FUF

Ten (10)
NESDR SMArt sets with antennas

Tim KJ6OIL
Joe KEODBJ
OK3OMG
James K3SE
John N1UMJ
Doug N2DW
Matt AE7DK
William WB6ANR
Egon VE6EGN
Richard WB2PEF

Ten (10)
NESDR SMArt SDRs

John W5AR
Rick K4NCX
Guy VA6GUY
James N1PZP
Landy KF5ZKR
Regis N1KXE
Rick KA0EGL
Bruno W6USC
Mike KD8KZT
Rich KB3NZV

If you’re a winner, check your e-mail for more details and don’t forget to enter our next giveaway scheduled for September.

If you didn’t win and you’re interested in ordering from NooElec, they’ve generously supplied us with a discount code for our readers:

AMRADIOTENOFF – $10 off orders $100 or more.
No restrictions.   Valid until 14 August 2016.

Thank you. again, to Jeff Crispino and the NooElec team. All of us look forward to more amazing giveaways!

Matt Thomas, W1MST, is the managing editor of AmateurRadio.com. Contact him at [email protected].