AmateurRadio.com

W7OS - Radio Club of Tacoma working the CX

This fall's running of the CW "Classic Exchange" will take place on Sunday, September 23 and on Tuesday, September 25. The following week will see the Phone "Classic Exchange", on Sunday, September 30 and on Tuesday, October 2.


The "CX" encourages participants to use older vintage gear including any homebrew equipment, both receivers and transmitters. A unique scoring system provides bonus points for various equipment and combinations as well as encouraging 'repeat contacts' when you switch to different equipment.

W8KM and his wonderful vintage station

No vintage gear? ... no problem! All amateurs are invited to participate and get in on the fun no matter what they are using and submit their scores.

K3MD's Heathkit AT-1 and Hallicrafters HT-37 ready for the CX

The CX is a low-key relaxing affair and the 'extra' Tuesday operating period should encourage a lot of midweek activity from the vast numbers of retired operators who cherish and run older gear.

Lots of combos ready at W4BOH's CX setup

K6ZI, Las Vegas - WWII ARC-5s ready to go

For complete details, see the web site announcement here.

If you've never entered the Classic Exchange, why not give it a try this year as it truly is a case of 'the more the merrier' ... and eastern operators, make sure to keep the porch light on for us out west!

In the years before amateurs in the UK had access to the 630m band as we know it today (472-479kHz), hams there could apply for a 'special research permit' allowing them to operate between 501 and 504kHz.


One of the first and most active stations was operated by Finbar O'Connor, EIØCF, located in the most northern part of Ireland, near Malin Head. In the early days, Finbar might as well have been AC4YN in Lhasa, Tibet, as a 630m or a 2200m QSO with EIØCF was a much prized DX trophy and a genuine 'right of passage' for many little backyard LF and MF stations throughout Europe.

Nowadays, 630m activity in Europe is not as robust as it once was but Finbar is still active on MF from his modest station. He reports being copied in North America on several occasions. Although mainly active in the WSPR mode, Finbar is now considering the two-way JT9 weak signal QSO mode and may hopefully once again, tease east coast North American MF operators with a new rare entity from his seaside location.

Finbar's WSPRlite setup for 630m

Over the years, EIØCF has gone portable as well as marine mobile to demonstrate the viability of this part of the spectrum for very reliable groundwave comms using equipment that is both simple and quick to deploy. Although he used a CW-based system, his conclusions could just as easily apply to SSB or digital modes.

EI0CF/marine on 630m!

What follows is a delightful adventure, in Finbar's own words, describing some of his field trips back in the 500kHz experimental days ... perhaps it will inspire some North American portable work or provide ideas for an emergency prep 630m grab-and-go kit, or just get you excited about our newest amateur allocation.


                                    ******************
              Operating Portable on 501 - 504 khz Medium Wave



Operations on the north flank of Slieve Snacht Inishowen Peninsula.

In June 2009 Ireland joined a growing number of countries permitted to operate on a small portion of the medium wave band, just below the commercial broadcast segment, in the range 501 - 504 khz. Several stations were granted permission and operations commenced. As has been documented elsewhere many stations have been worked, both in band and cross band, at home and abroad, ranging from Continental Europe, across the Atlantic to the USA and Canada, down to the southern end of Ukraine and finally up to Iceland, Norway, Sweden, Finland and also being heard in Moscow.

A notable feature of this band is the steady reliable nature of groundwave coverage and with this in mind I recently availed of the facility whereby portable operations can take place. Comreg, together with the IRTS and the individual involved, require that each event is applied for, giving relevant dates, location, contact details, hours of operation and the power of the transmitter being used.

In the period leading up to all this it was necessary to build and test a viable portable station based on the use of my Berlingo van. A 30' part of a 40' Spiderbeam fibreglass  pole was used with a simple round wooden peg to secure the 'Tee' wire antenna, which was fabricated from twin twisted multistrand speaker wire. The vertical used both, while the rest was pulled apart to form the two horizontal legs.

A 100 metre roll of 1.5 mm insulated earthing wire was cut into 16 lengths to provide radial wires, with lugs soldered to one end and a bonding bolt used to secure a single point for the radial kit. The far ends formed a small loop which was sealed and secured with insulating tape. The loop provided an eye for a small L shaped stiff wire, fashioned from discarded coat hangers, an ideal and cheap way to hold the ends of the radial wires in place in the ground.

To secure the antenna support to the van, I refer you to the excellent idea described by John EI7BA, on his web page, for a ball hitch connection:

http://www.qsl.net/ei7ba/a_ball_hitch_mobile_mount.htm

Using this superb idea, I got the welder out and made one for myself. It worked perfectly.

I now had the support and wire antenna, with a ballpark figure for what might resonate, along with the radial kit. I next needed a dedicated antenna tuning unit. An old variometer and two extra fixed multitap coils were selected. A home made 1 amp ammeter and SWR twin meter unit completed the fit-out. These were all assembled on a base with a handle on the top, making it easy to move around whilst out and about.

The main antenna for 500kHz was disconnected and left floating and the van set up with all this gear, but no transmitter. Instead, my little antenna bridge running off a 9-volt battery provided the necessary signal to start testing for basic resonance.

Whether from sheer good luck or some sub-conscious input, resonance fell within the range of the variometer with only one of the two extra coils in circuit. The relative height and length also play a part in the range of resonance secured. Matching to 50 ohms was then optimized by selecting 4700 pf Mica capacitors using Croc Clip links. The available value ranged from 1 nF to 14 nF.

I have a selection of 500khz transmitters, two of which are to the design of Roger, GW3UEP, who lives 10 miles inland from the coast, in south Wales. His 500khz web site is well worth checking out, containing plans for versions of his 500khz transmitters, test equipment pictures and recordings of 500khz activities.

http://www.gw3uep.ukfsn.org/

One of these was used to put some RF into this first portable style installation, and by arrangement, Roger listened and heard my signal. We delightedly completed a short contact, with my transmitter running just 10 watts.Things were looking good.

One of the very valuable things about portable operations stems from the need to bring together several elements to secure a working radio station, without the usual backup we enjoy from home. Planning is essential. Doing a dry run, i.e. actually physically building the intended station then notating all the gear required and making a list as well as providing backup items, particularly those that which if broken or lost, would render the whole radio station non-viable. This also extends to the operator of the equipment. Will they be warm or cool enough, have shade, food, water and enough needed rest? Always be prepared to abandon the project if safety is compromised, for whatever reason.



Now that I had a viable portable station for 500kHz working, it was time to head off and test both the equipment and myself in the real world, but without any live transmissions taking place.

Several sites were chosen and tested, with particular emphasis placed on remoteness, i.e. high up on mountains or near the sea. All sites worked very well, but those by the sea proved really excellent. Reception of NDB’s (Non Directional Beacons) provided a ready supply of medium to low frequency signals for range testing. I was now itching to “ have a go “ out in the wilds, on 500kHz! Using the method required by Comreg, an application was made for several sites, on specific days.




In early June I loaded up the van with all the gear and headed off for the mountain above Redcastle, County Donegal. Using a narrow track and climbing higher, to about 270 meters, a place was found leading to an old quarry. Typically, it had started to rain. By the time I had erected the support pole, pulled out and secured the top hat wires using light nylon line and deployed the radial wires around and below the vertical drop wire, my trouser ends were very wet!

Plugging in the 12-volt supply, the receiver was very quickly perked up, using the variometer. The Morse key connected to the QTX transmitter and the transmit / receiver switch flicked over. Time to get some RF flowing in the antenna. Sure enough, on key down, the antenna current meter shot right up to 400 mA, but the SWR match was not exactly perfect. Time to work those Croc Clips and start selecting shunt capacitors to find the perfect match. Soon I had that sorted to my satisfaction, with antenna current now up to 550 mA. A quick return to receive showed that Roger, GW3UEP was already tuned up on frequency.




"..... GW3UEP DE EIØCF/P HW K"

He came back straight away! Oh joy, we were on the air on 500, in a remote mountain area, the top of my antenna almost tipping the clouds as they swept past. I was open to the elements, standing at the back door of the van with the tips of my fingers reaching for the knob of my very favourite old Amplidan morse key, snug beside the other bits and pieces of equipment on the van floor!

My logbook, with its pages flapping back and forward in the wind, soon had the first 500kHz portable contact documented. A full hour later, solid steady signals continued at a distance of 250 miles. Proving just how good groundwave signals can be, I terminated communications from the remote portable location, happy with the results. Within 12 minutes I had dismantled the station and was on my way to Moville, along with a strong cup of coffee at the café on the town's main street.

Several other portable operations have since taken place. A number have also occurred at my home location. We live right beside the sea; high tides lap up on to the salt marsh, which is part of the property.




Driving a single earth rod into the sea shore to a depth of 1 metre, with no radials and just a single wire between the rod and the ATU earth, the 1 amp RF meter had its meter needle slamming against the end stop. Lots of antenna current for 15 watts transmitter output power. Those same 15 watts only providing, at best, 550 mA, whilst up on the mountain sites.

Finally, it was thought productive to try a kite-supported antenna from the seashore portable set up. Winds on the day selected seemed strong enough to enable my Delta shape kite to head aloft with a flying line and antenna wire attached. The Berlingo van was driven down on shore, everything connected and tuned up. All was well, or was it?

The receiver now seemed quite dead with no band noise and no antenna current on transmit. Looking skywards I could see nothing. My eye followed the antenna wire heading for deeper water. Then I saw it. The kite had plunged into the sea! The following 30 minutes entailed untangling loads of seaweed with the line wrapped around rocks, barnacles and everything imaginable. What a mess! I almost gave up, but knew that Roger would be coming up on frequency, on sked, in about 15 minutes.

Eventually I managed to get the kite skywards again but by now the wind was acting more unpredictably. I established contact with Roger and he immediately gave me an S 7 report for my 15 watts. This equated to the report I would get from my main station antenna running 100 watts. My single ground rod and 150 feet of wire were doing the business.

We carried on our contact, but what remained became a battle of wits, with a kite constantly diving down and soaring up again. Several times the antenna wire was in part lying on the sea shore and antenna current way down to 200 mA or lower. My left hand was on the variometer tuning knob, tweaking the setting as best as possible, while pulling in the slack to keep the antenna wire off the ground. Feeding the wire out again to a misbehaving kite, I kept keying away with my right hand, keeping Roger updated so he could understand why my signal was changing both in pitch (sudden antenna mis-match conditions) and signal strength.

Luckily he was also making a recording, which proved later to be a fascinating record of a difficult portable antenna and station operation. It’s remarkable how tolerant, despite the wildly changing antenna conditions, the system actually was in practice. Communications were maintained despite all these negative factors and severely decreased radiated power at times.


Several other tests were conducted within these experiments which would have been almost impossible to conduct without the challenges thrown up by my portable operations. To my mind the 501 – 504khz band exhibits a distinct advantage for enhanced groundwave coverage over that available to higher frequencies.

Relatively simple equipment deployed in remote locations, with or without the availability of the power grid, would provide a solid backbone link or network in times of emergency. Transmitter power output was kept deliberately low to ensure that a higher ERP would not mask any possible weakness in the system. I am happy to conclude that Medium Frequency CW proved it’s worth once again.

Already I have further plans to test smaller, more compact portable antenna and earthing systems in more remote locations.

Finbar O’Connor EIØCF Malin, County Donegal.

BF-362 Seattle

courtesy: NOAA

My log consisted of 30 stations, with all but two from Friday night before the storm. As usual, the receiver was a Perseus SDR and an 'Inverted-L', resonated at 300 kHz.
25 12:00  350     SWU   Idaho Falls, ID, USA
25 08:00  350     RG   Oklahoma City, OK, USA
25 07:00  350     NY   Enderby, BC, CAN
25 07:00  351     YKQ   Waskaganish, QC, CAN
26 12:00  352     RG   Rarotonga IAP, CKS
25 07:00  353     ZXY   Whitehorse, YT, CAN
25 08:00  353     PG   Portage La Prairie, MB, CAN
25 13:00  353     LLD   Lanai Island, HWA
25 07:00  353     AL   Dixie, WA, USA
25 12:00  355     AUB   King Salmon, ALS
25 12:00  356     ZXE   Saskatoon, SK, CAN
25 08:00  356     ZF   Yellowknife, NT, CAN
25 08:00  356     PND   Portland, OR, USA
25 08:00  356     ON   Penticton, BC, CAN
25 12:00  356     MEF   Medford, OR, USA
25 09:00  358     SIT   Sitka, ALS
25 09:00  359     YQZ   Quesnel, BC, CAN
25 09:00  359     YAZ   Tofino, BC, CAN
25 07:00  361     HI   Holman, NT, CAN
25 07:00  361     E3   Wabasca, AB, CAN
25 07:00  362     YZS    Coral Harbour, NU, CAN
25 07:00  362     RPX   Roundup, MT, USA
25 07:00  362     BF   Seattle, WA, USA
25 08:00  362     6T   Foremost, AB, CAN
25 07:00  365     YGZ   Grise Fiord, NU, CAN
25 12:00  365     MA   Mayo, YT, CAN
27 08:00  365     DPY   Deer Park, WA, USA
25 07:00  365     AA   Harwood, MN, USA
25 12:00  368     ZP   Sandspit, BC, CAN
25 12:00  368     VX   Dafoe, SK, CAN

The results from ALL participants may be viewed here.

BF-362 courtesy: Steven M O'Kelley

This coming weekend will see another monthly CLE challenge. This time the hunting grounds will be 350.0 - 369.9 kHz.

 


For those unfamiliar with this monthly activity, a 'CLE' is a 'Co-ordinated Listening Event', as NDB DXers around the world focus their listening time on one small slice of the NDB spectrum.

A really good challenge in this one is to hear BF-362, located in Seattle, Washington. I suspect that it's a 25-watter but is rarely logged outside of the Pacific Northwest region. If you are east of Montana and can hear it, your system is working well!

Listen for BF's  upper-sideband CW identifier (with your receiver in the CW mode) on 363.030 kHz while its lower-sideband can be heard on 360.943 kHz.

Although we are getting ever-closer to the fall DX season, lightning storms may yet be a problem, but at this time of the year we may get a lucky few quiet nights like this one in mid-June.

courtesy: http://thunderstorm.vaisala.com/explorer.html

If you are interested in building a system for the new (U.S.) 630m band, the CLE will give you the chance to test out your MF receiving capabilities and compare against what others in your area might be hearing.

When tuning for NDBs, put your receiver in the CW mode and listen for the NDB's CW identifier, repeated every few seconds. Listen for U.S. NDB identifiers approximately 1 kHz higher or lower than the published transmitted frequency since these beacons are modulated with a 1020 Hz tone approximately.


For example, 'AA' near Fargo, ND, transmits on 365 kHz and its upper sideband CW identifier is tuned at 366.025 kHz while its lower sideband CW ident can be tuned at 363.946 kHz. Its USB tone is actually 1025 Hz while its LSB tone is 1054 Hz.

Often, one sideband will be much stronger than the other so if you don't hear the first one, try listening on the other sideband.


Canadian NDBs normally have an USB tone only, usually very close to 400 Hz. They also have a long dash (keydown) following the CW identifier.


All NDBs heard in North America will be listed in the RNA database (updated daily) while those heard in Europe may be found in the REU database. Beacons heard outside of these regions will be found in the RWW database.


From CLE organizer Brian Keyte, G3SIA, comes the details:


Hello all

Here are the full details for this weekend's co-ordinated listening event.
It is open to everyone including CLE new-comers:

Days: Friday 24 August - Monday 27 August
Times: Start and end at midday, your LOCAL time
Range: 350.0 - 369.9 kHz

This range is a busy one, usually giving us a high number of NDBs heard.

We last concentrated on these frequencies during CLE219 in May 2017.

Wherever you are, please join us and log the NDBs that you can positively
identify that are listed in this busy frequency range (it includes 350.0 kHz
but not 370 kHz) plus any UNIDs that you come across there.

Send your CLE log to the List, preferably as a plain text email
(not in an attachment) with "CLE235 - FINAL Logs" at the start of its
subject line.

Please show on EVERY LINE of your log:

# The date ( e.g. 2018-08-24  or just the day no. 24 ) and UTC
(the day changes at 00:00 UTC).
# kHz (the beacon's nominal published frequency, if you know it)
# The Call Ident.

Show those main items FIRST on each line, before other optional details
such as Location, Distance, Offsets, Cycle time, etc.

If you send any incomplete logs to the List during the event, please also
send your 'FINAL', complete one.

Please always make your log interesting to everyone by showing your
own location and brief details of the receiver and aerial(s), etc., that
you were using.

We will send the usual 'Any More Logs?' email so that you can check that your log has been found OK.


You can check on all CLE-related information from the CLE Page

http://www.ndblist.info/cle.htm

It includes a link to seeklists for the Event from the Rxx Database.

Good listening
Brian
----------------------------------------------------------
From: Brian Keyte G3SIA ndbcle'at'gmail.com
Location: Surrey, SE England (CLE coordinator)
----------------------------------------------------------

(REMINDER: You could use any one remote receiver for your loggings,
stating the location and owner - with their permission if required.
A remote listener may NOT also use another receiver, whether local
or remote, to obtain further loggings for the same CLE). 
-------------------------------------------------------------------

This past weekend's 'Barn Door' CLE' saw a lot of participation, in spite of the mid-summer doldrums and the universal nasty lightning noise.


After reading CLE-organizer Brian Keyte's interesting posting to the ndblist, describing his homebrew single transistor regenerative receiver, I was inspired enough to dig out the soldering iron and build one for myself.

The circuit widely described as a '1AD regen' was originally designed several years ago by crystal-radio guru Mike Tuggle out in Hawaii. Mike is widely known for his exquisitely designed "Lyonodyne" DX crystal radio, which inspired an entire decade of intense DX crystal radio building activity back in the late 90's.

Mike Tuggle's 'Lyonodyne' DX Crystal Radio

His  '1 Active Device' medium-wave regen consists of a handful of simple components and a MOSFET that is up to the task. His design was, and still is, being duplicated by many throughout the NDB DX listening community.

Mike's original 1AD regen

Mike recently sent me the circuit diagram that he eventually settled with, showing two possible ways of extracting audio with the widely popular Bogen T725 output transformer.



My own version used Mike's output scheme on the right and the RF circuitry in Roelof Bakker and Steve Ratzlaff's modified version, shown below. I had to increase the tickler (feedback) winding from 4 turns to 11 turns in order to get any regeneration. With 11 turns, my regeneration kicked-in at about three-quarters from the end of the regen control. At some point in time, while testing, some of the leads from my Bogen T725 output transformer momentarily brushed against each other, smoking my FET. Upon replacing it with another BF966, the receiver was much hotter, with regeneration kicking-in very close to the start of the pot. I'm not sure if the first FET was already damaged or that there is enough variation from FET to FET (of the same type) to make some have more gain than others. Accidentally blowing up the FET proved beneficial in the end!



Although most users employ sensitive sound powered headphones with their regens, including myself, some use modern phones with an extra stage of audio, such as an LM386.

Although not nearly as pretty as Mike's regen, my own 1AD was built in an afternoon, just for the recent Barn Door CLE.

My own MW 1AD regen

I later added a calibrated dial plate, breaking the segment from 200kHz to 550kHz into two separate bands, with calibration ~ +/- 1kHz so that I pretty much new where I was tuning at all times. This allowed me to target specific beacons and wait for them to fade up.

When first published, Mike suggested the BF966 MOSFET seemed to work well and I purchased five of them with the intention of someday building a 1AD for the NDB band. The purchase came in handy, as today, the BF966 is no longer available. Apparently the similar, and still available BF998 works well (from tests done by Steve Ratzlaff) but is now in an SMD package at just 18 cents! No doubt there are dozens of MOSFETS that will do the job and at these prices, experimenting with various devices would be a very worthwhile project.

When operating, the regen proved to be surprisingly sensitive, and by using my 10' x 20' loop, I was able to put my local pest (AP-378 kHz and 1/2 mile away) into a deep null so that its huge signal was no longer blocking the top half of the NDB band. The null allowed me to hear beacons within a few kHz of the blowtorch signal as shown below:

This coming weekend will see the 'Barn Door' CLE, mentioned in a previous blogspot here. Listeners are required to challenge themselves by listening on a receiver using a wide enough bandwidth that several kHz worth of signals can be heard at once.




The 'immersive' effect this wider bandwidth mode provides is much different than when listening with narrow filters and can make digging out IDs a lot more challenging. Throwing in some mid-summer lightning noise makes it even tougher, but if it were easy, it just wouldn't be much fun!

Many, including myself, will be using homebrew single MOSFET regenerative receivers, often called a '1AD' since they normally use just one active device. I've just finished testing my own version and have been able to hear some night time DX so hopefully the band will be quiet enough to hear some signals during the CLE.

From CLE organizer Brian Keyte, here are the details explained ... and good luck to all participants!

Hi all

It is an opportunity to bring back to life basic kinds of receiver - anything with low selectivity which allows you to hear NDBs on several frequencies simultaneously - leaving the barn door wide open!

Listening with 'back to basics' equipment often gives very satisfying and unexpected results.  It can also show us ways of improving our listening when operating more normally.

Our last Barn Door CLE was No. 209 in July two years ago.

Here comes our fifth 'Barn Door' CLE.  Between us there will be a great variety of different receiver types in use.

    Days:      Friday 27 to Monday 30 July 2018
    Times:    Start at  ## 11 a.m. on Friday 27th, your LOCAL time
                   End at   ## 3 p.m. on Monday 30th, your LOCAL time
    Frequencies:   Centred on 360 kHz (see below)
    NDBs:     NOT MORE than 100 'normal' NDBs including any UNIDs
                   (That is not intended to be a target to reach)

We are all asked to listen with NON-SELECTIVE receivers - i.e. with a WIDE
filter or NO filter.  Your 'barn door' should be open wide so you could
hear, at the same time, any NDBs 2 kHz away on both sides of your receiver
setting - E.g. NDBs on 348, 349, 350, 351 and 352 kHz with the receiver set
to 350 kHz.

## The extra daytime hours on the first and the last day might help some of
us planning to listen out of doors.

You could listen with:

1. A simple home-made receiver, such as a single transistor set with regen.
    (e.g. based on the sets used by Mike, Finbar and others).

2. OR - an Ultralight receiver, maybe one converted to cover the NDB
    frequencies with a modified aerial.

3. OR - an 'antique' receiver (e.g. Eddystone, R1155, Scott, etc.)
    Perhaps you have something you've not switched on for many years?

4. OR - a normal receiver but with NO filtering, or using a WIDE FILTER,
    (not less than about 2 kHz and no selection of an audio filter).

You choose how wide a RANGE of frequencies you will listen in, CENTRED ON
360 kHz.  You could choose 350-370 kHz or 330-390 kHz or 260-460 kHz, etc.
   (This allows each of us to choose a +/- range with enough NDBs to
   match our equipment's capability.  It will also allow our loggings to
   be compared in the Combined Results, at least around 360 kHz).

Logs should show NOT MORE THAN 100 NDBs please (if more than 100, the
harvester program will 'drop' the loggings furthest from 360 kHz).

There are several extra targets you could set yourself - maybe the wide
bandwidth, the centre frequency of 360 kHz and the 100 loggings limit do not
challenge you enough!

You could listen only in daytime and/or away from home.
Or how about NDBs on 360 +/- 10 kHz or even +/- 5 kHz?
The Twente remote receiver in Holland could be interesting to use for the
whole of your (only) CLE log.
( Go to http://websdr.ewi.utwente.nl:8901/ and read the advice there:Select AM and 'MAX IN', enter e.g. 354.7 in the frequency box and change the
filter's limits to 2 or 3 kHz from the centre frequency on both sides )

We’ll summarise everyone's equipment on the first page of the combined
results, so please describe:
The RECEIVER/AERIAL you used and the FILTER(s) selected, if any.
If homebrew, please quote:  the total number of active devices used –  e.g.
1 for a single transistor stage ( 1AD ) -  the transistor/valve types,
whether using regen.,  etc.

All the usual procedures for making logs apply:

Send your CLE log to NDB List, if possible as a plain text email and not in
an attachment.

Please show on EVERY LINE of your log:
    # The full date (or Day No.) and UTC (the day changes at 00:00 UTC).
    # kHz - the beacon's nominal published frequency, if known.
    # The Call Ident.

Show those main items FIRST on each line, before other optional details
such as Location, Distance, etc.  Please send your complete log with
CLE234 and FINAL  in the Subject line.

Whether you are a first time CLE-er or a regular, make your log interesting
to everyone by showing your own location and your equipment details.
Do feel free to share any comments you have on this unusual event.

Joachim or I will send the usual 'Any More Logs?' email at about 17:00 UTC
on Tuesday 31st so that you can check that your log has been found OK.
Make sure your log has arrived on the List at the very latest by 08:00 UTC
on Wednesday 1 August.   We hope to complete making the combined
results a day or so later.

However you choose to take part, we hope you will find your 'back to basics'
listening enjoyable and worthwhile.


P.S.   NOT FOR YOU?

Listening without narrow filters is not going to revolutionise our hobby!
But there ARE some unexpected benefits and advantages:

1. Hearing several beacons on a few adjacent frequencies at the same time
becomes easier as you get practice at recognising them by listening to their
very different audio tones. At first, when listening to a random frequency
setting, you may hear just one or two beacons. But after listening for a
little while you realise that there are three - - four, maybe more, all of
them audible without altering any of the receiver controls.
It is a skill that gives satisfaction as you improve.

2. Hearing multiple beacons like that can be useful because, with no extra
tools, you can hear NDBs over a wide frequency range much more quickly than
usual, perhaps spotting the arrival of new UNIDs or the return of occasional
beacons.  (To protect your hearing, keep your receiver gain controls fairly
low, except on very quiet frequencies).

3. With normal listening it is easy to miss any NDBs that have abnormal
carrier frequencies or non-standard offsets.  With 'Barn Door' listening
they won't escape because everything is let through.

4. When using a wide filter, you may be surprised by hearing some Broadcast
Station signals (e.g. harmonics) among the NDBs and you will be able to
identify them.
With a narrow filter, often you may not recognise an AM signal as audio
- it just sounds like nondescript 'hash' affecting a wide range of
frequencies around the central carrier.


Maybe listeners will report some other good things about their barn door
listening during the CLE - and probably some bad things too!

Do join in if you can.

   Brian
----------------------------------------------------------
From:   Brian Keyte  G3SIA          ndbcle'at'gmail.com
Location: Surrey, SE England         (CLE coordinator)
----------------------------------------------------------

Don't forget that help and chat regarding NDB DXing can be had on the ndb group list here.