Date   

Re: Recent FSL Antenna Experimentation

Robert Conboy
 

 

 

I have determined that broadband FSL’s don’t work very well for broadband recording with an SDR to sift thru later, unless wound on a large amount of ferrite. A broadband winding on a small FSL might be useful for live dx using an SDR, to help identify a frequency to tune to. Furthermore, I have not yet explored broadband enhancement for a inductively coupled small portable, relying exclusively on the the portable’s selectivity. It would entail using a bias tee, power supply or battery, and an inductive coupler probe.

 

My testing used a Wellbrook ALA1530LN as a reference antenna and a Perseus receiver. Perseus has a true 50 Ohm resistive input.

The FSL broadband amplifier is a Wellbrook FLX1530LN which I think is the same amplifier as the reference but in a different package.

 

I used copper tape to prototype, using various widths, and tapped the amplifier in at various points to determine the best broadband windings.

 

4 turns of 1-1/2 inch wide flashing wound on a 49 rod 200 mm long FSL yielded signal amplitudes 10 dB below the reference antenna, while the QRN daytime noise floor was about 11 dB below the reference.

 

2 turns of 2-1/2 inch wide flashing wound on a 204 rod 600 mm long FSL (68 rods x3) yielded amplitudes 3 dB below reference, and the daytime noise floor was about 6 dB below reference, (while still above the radio’s own noise floor). I don’t know why the large FSL consistently is yielding better performance than the reference antenna. My guess is that directional nulls of the FSL are broader and deeper than the Wellbrook loop’s and therefore the FSL is intercepting less QRN from some directions.

 

This antenna has broadband and tuned outputs. The tuned portion has a variable selectivity control. 

 

It’s grossly impractical, heavy and the cost of materials was more expensive than I will admit, even here, but its performance is nothing short of amazing.  First off, the field around this antenna is immense. It begins enhancing reception of a portable within about 6 feet.    Selectivity is adjustable. The narrower the selectivity, the greater the sensitivity. Tuning for dx is a balance between bandwidth, sensitivity and offset. Those of us with experience dx’ing with an old Hammarlund that has a regenerative selectivity control should remember what this is like.

 

The ferrite sleeve is 24 inches long and 9 inches diameter and made from 204 eight inch ferrite rods mounted on the outside of a 8-inch i.d. PVC pipe.  There is a 2-rod-width gap along the length of the sleeve that serves a dual purpose. It’s where the coil connections are made, as the electronics are inside the pipe. It also creates a gap to cut down magnetic coupling between conductors that run along the length of the sleeve. Without the gap, the sleeve becomes a toroidal core. The gap runs along the bottom of the sleeve for symmetry.

 

BTW, the 200mm by 10mm ferrite rods were still available on eBay last I looked, from a supplier in China. The specs aren’t given which is probably why they they haven’t been discovered by the dx community (as far as I know), but they appear to be mix 61. 

 

I bought 5, to check their suitability. After some testing and measurement, I was able to determine their permeability is above 100. So I bought 20 more, then 50, then 200.  Mix 61 is commonly used for AM loopstick antennas.

 

Tuned coil: 12 turns 1100/48 Litz, 230 uH, Centered on ferrite sleeve.

 

Capacitor:  20-400 pF, semi- logarithmic taper, 3-turn vernier shaft. This is mounted in the center of the ferrite sleeve (inside it) at the same depth as the coil.  This location was chosen after experimentation. I noticed that a small portable (Tecsun PL-330) placed inside the ferrite sleeve (before winding any coils) had greatly attenuated reception at some spots inside the pipe. So I wound a sniffer probe on a rod and connected it to my Perseus. There is a deep broadband null along the center axis that is greatest halfway in. I chose this spot for the tuning capacitor. The shaft is connected to an acrylic extension shaft with an insulated coupler. The coil/cap combination tunes from 525 to about 1850 kHz. Details on mounting come later.

 

The tuning knob is a dual concentric 1:1 and 40:1 vernier from Ukraine I bought on eBay. When combined with the vernier drive on the capacitor, it takes 120 turns of the inner knob to fully open/close the capacitor. The outer knob takes 3 turns. This makes pinpoint tuning at narrow bandwidths easy. Unfortunately there is some slop in this vernier when reversing rotation. It takes about 1/10 rotation before the rotor plates move. It’s inconsequential with such an extreme vernier ratio, but with a 1:1 shaft capacitor (40:1 vernier instead of 120:1) the slop was intolerable.

 

The pickup coil has 7 uH, is two widely spaced turns of 1100/48 Litz. The pickup coil feeds a step down transformer. This pickup coil is located 4 inches from one end of the ferrite sleeve. 

 

Step Down transformer: BN-73-202 core, 

Primary: 15 turns 64/46 Litz

Secondary: 3 turns 64/46 Litz.

 

The purpose of this transformer ratio is so that the pickup coil places a very light load on the tuned circuit. It also serves as a balun between the pickup and the amplifier. This is critical.

 

From the transformer it goes to a Mini-Circuits low noise amplifier model ZFL-500LN with a 50 Ohm input. This amplifier, due to the mismatch introduced by the transformer, places a 1250 Ohm load on the pickup coil and the amplifier’s effective gain is reduced to about 16 dB from 30 dB

 

Amplifier output goes to a Mini-Circuits signal splitter which reduces the gain by another 3 dB while isolating the feedback circuit from any connected radios.

 

Port one of the splitter goes through a 6 dB attenuator to a Mini-Circuits bias tee for powering the amplifier. This attenuator reduces the possibility of overloading the front end of a radio.

 

The RF+DC port of the bias tee goes to a BNC jack to connect a radio (via an external bias tee). The amplifier gain here is now about 6 dB.  

 

Port 2 of the signal splitter goes to a 10 dB attenuator.  This makes about 3 dB of gain available for feedback.

 

The output of the attenuator goes to a Bourns 10-turn 500 Ohm potentiometer. 

 

The output from the potentiometer goes through a switch to the feedback coil.

 

Between the switch and the feedback coil is a common mode choke balun: 5 bifilar turns around a small mix 75 toroid

 

In series with the feedback coil is 100 Ohms in parallel with 1330 pF. This makes the feedback slightly favor higher frequencies. This high pass filter makes potentiometer feedback adjustment less touchy when changing frequencies.

 

Feedback coil: 1-turn of 1100/48 Litz wire located 4 inches from the end of the ferrite sleeve opposite the pickup coil. Choosing Litz wire here might be complementary to the high pass filter but may yield no advantage over common wire..

 

Broadband  pickup coil:  Two turns of 2-1/2 inch wide copper flashing. They are wound on opposite sides of the tuning coil. 

 

This broadband coil goes through a DPST switch to a Wellbrook FLX1530LN low impedance loop antenna amplifier. The switch is necessary or else the broadband loop behaves like a partially shorted turn when using the the tuned portion of the antenna.

 

The output of the Wellbrook amplifier goes to a BNC jack.

 

The entire assembly is housed in a Rubbermaid trashcan liner.

I used 12 inch and 8 inch diameter wooden discs to center the antenna in the liner at the control panel end. The 12 inch disc fits into the liner, the 8 inch disc fits into the pipe, and the discs are glued together. The electronics are mounted on the outside of a 4 inch diameter, 11 inch tall plastic jar. The jar is mounted in the 8 inch wooden disc. The jar’s threads are lined with teflon tape. The 8 inch disc is cut with a 4 inch hole saw. The jar is mounted in the 4 inch hole using paste epoxy. This jar extends halfway down the center of the pipe. The teflon tape makes it so the jar can be unscrewed. The capacitor is mounted on the outside bottom of the jar, level with the tuned coil. Its shaft runs trough the inside of the jar to the vernier knob outside of the assembly. 

 

I built up the opposite end of the antenna with 2 inch wide strips of neoprene rubber to center it into the liner. 

 

Three modes of operation: 

 

Active tuned antenna with variable selectivity control, powered through a bias tee such as a Wellbrook antenna interface. Tune-able range 525 kHz to 1.85 MHz.  Measured narrowest possible (stable) -3 dB bandwidth @ 1750 kHz is about 80 Hz, making maximum possible Q about 22000 before oscillation.  In use, Q is dialed lower than this because a radio is not a subwoofer. 

 

The other mode is a Broadband antenna with it’s own separate coil and Wellbrook loop amplifier. This is usable up into the shortwave bands but performance gradually begins to degrade above about 2 MHz.

 

Passive mode, amplifiers unpowered. A tuned FSL that is proximity coupled to any nearby radio that has an internal loop antenna. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Re: FM Translators - Why?

Peter Laws
 

On Mon, May 31, 2021 at 1:57 PM Johnny via groups.io
<jlochey=yahoo.com@groups.io> wrote:

Hi all,

Why do FM Translators exist?
Because the FCC says that this is how to "revitalize" AM broadcasting.

¯\_(ツ)_/¯

--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


FM Translators - Why?

Johnny
 

Hi all,

Why do FM Translators exist?

The closest I can tell is that they exist to give an AM station a "Market Presence" in the FM band at a local level.

Is that pretty much it?  Or am I missing it?

Also, I have not come across an FM Booster yet, but apparently these exist (in the US at least).


Johnny


Re: My best FM DX'ing catch so far!!!

Johnny
 

Hi John,

I was using my R-108.

A GREAT radio!


Johnny


Re: Recent FSL Antenna Experimentation

Gary DeBock
 

On Mon, May 31, 2021 at 09:18 AM, <robconboy@...> wrote:
Well, I just unsuccessfully attempted to post a lengthy reply full of technical details but it would not post, or needs to be reviewed by a moderator or something...
Hi Rob,

Moderator approval isn't needed for lengthy messages, so you should be good to go. It's only set up by Groups.io for the first message sent by a new member, in order to avoid spam postings.

73, Gary DeBock (in Puyallup, WA, USA)


Re: Recent FSL Antenna Experimentation

Grant
 

hoping that you get it published, really want to see it - thanks, Grant


Re: Recent FSL Antenna Experimentation

Robert Conboy
 

I will try again later. The post was cobbled together from my various build notes which I still have.


Re: Recent FSL Antenna Experimentation

Phil Pasteur
 

That is too bad. I would really like to see the information. Maybe one of the mods can help you with it. Hopefully the post was saved somewhere.


Re: Recent FSL Antenna Experimentation

Robert Conboy
 

Well, I just unsuccessfully attempted to post a lengthy reply full of technical details but it would not post, or needs to be reviewed by a moderator or something...


Long Term DX Project - 29/05/2021

Paul Blundell
 

Date: 29/05/2021
Time: 4:15pm
Location: Home, Launceston Tasmania.
Radio: AR-1733 / 3” FSL
Notes: A late afternoon session at home, using my AR-1733 and 3” FSL. Signals were a real mix with only two of the 50kw big guns hitting good signal levels. Even 3GG on 531kHz struggled a bit. Both the HPON stations were only logged at poor signal levels.

 

Long Term DX Project Loggings:

FREQ

CALLSIGN

LOGGED

Area Served

Purpose

Power

531

3GG

AVERAGE

Warragul

Commercial

5k

549

2CR

POOR

Cumnock

National

50k

594

3WV

AVERAGE

Horsham

National

50k

621

3RN

GOOD

Melbourne

National

50k

774

3LO

GOOD

Melbourne

National

50k

1053

2CA

UNLOGGED

Canberra

Commercial

5k

1179

3RPH

UNLOGGED

Melbourne

Community

5k

1341

HPON GEELONG

POOR

Geelong

HPON

5k

1422

HPON MELBOURNE

POOR

Melbourne

HPON

5k

1503

3KND

UNLOGGED

Melbourne

Community

5k


Re: Recent FSL Antenna Experimentation

Nick Hall-Patch
 

Have you published details of your broadband amplified FSL, Rob?  

I don't know if others have tried the copper flashing for a pickup winding.   How different is its response from using a simple loop of wire to transfer the FSL's signal to the amplifier?   And, is the amplifier itself a unique design?

Thanks.

Nick


Re: My best FM DX'ing catch so far!!!

John
 

Good DX Johnny. What were you listening with?

John


On Sat, May 29, 2021 at 7:00 PM Johnny via groups.io <jlochey=yahoo.com@groups.io> wrote:
Hi all,

Just had to share...

I heard my 2nd Translator station and was pretty excited!

W227BY-FM (Translator for 1510 AM in Jackson, Michigan)

44 miles away, 130 watts and only 68 feet high of an antenna!

Really cool!


Johnny


Re: Recent FSL Antenna Experimentation

Robert Conboy
 

I have to agree, from my experience, and for mostly practical reasons, a smaller FSL is a better choice for dx.  

I’ve recently built 3 different ferrite sleeve loop antennas using 200mm x 10 mm mix 61 rods:  19 rods housed in 1 and a half plastic metamucil jars, 46 rods on a 6 inch exercise roller wrapped in neoprene, and 204 rods on 2-feet of 8 inch id PVC pipe housed in a rubbermaid trashcan liner. My little 19 rod fsl, from a reception standpoint, is 80+ percent as good for dx as the 50 lb behemoth, but I can pick it up and carry it with one hand, and pack it in a suitcase.

There are a couple or 3 differences between my designs and others I have seen online.

They’re housed in protective enclosures. They look like cylinders with knobs, switches and jacks on one end. No electronics is visible. 
They have adjustable regenerative feedback, but work well passively too.
The two larger ones each have separate, switched, low impedance windings of copper flashing and low noise amplifiers for broadband response.  

Rob, Westford MA


My best FM DX'ing catch so far!!!

Johnny
 

Hi all,

Just had to share...

I heard my 2nd Translator station and was pretty excited!

W227BY-FM (Translator for 1510 AM in Jackson, Michigan)

44 miles away, 130 watts and only 68 feet high of an antenna!

Really cool!


Johnny


Re: Awards Program

Paul Blundell
 

Portable Radio RXing Awards Program.

I have decided to split this off as a separate group, as while the focus is on the "ultralight" side, I want to encourage anybody with an interest in radio to join in.

On Fri, May 28, 2021 at 10:16 AM Paul Blundell via groups.io <tanger32au=gmail.com@groups.io> wrote:
Thanks Johnny, I don't see the admin side of this being too much at this stage, it is more about getting enough people keen and deciding how the program will work / look.

On Thu, May 27, 2021 at 9:25 PM Johnny via groups.io <jlochey=yahoo.com@groups.io> wrote:
Hi all,

I'd love be a part of an awards program!

Let me know if I can help!  I could volunteer 2-4 hours a week if needed to help.

Love the ParkRX idea!  My wife and I are avid hikers.

Thanks,

Johnny



--
Paul



--
Paul


File /PortableRXingAwardsProgram.pdf uploaded #file-notice

main@UltralightDX.groups.io Notification <noreply@...>
 

The following files have been uploaded to the Files area of the main@UltralightDX.groups.io group.

By: Paul Blundell <tanger32au@...>

Description:
Portable Radio RXing Awards Program.


Re: Awards Program

Paul Blundell
 

Thanks Johnny, I don't see the admin side of this being too much at this stage, it is more about getting enough people keen and deciding how the program will work / look.


On Thu, May 27, 2021 at 9:25 PM Johnny via groups.io <jlochey=yahoo.com@groups.io> wrote:
Hi all,

I'd love be a part of an awards program!

Let me know if I can help!  I could volunteer 2-4 hours a week if needed to help.

Love the ParkRX idea!  My wife and I are avid hikers.

Thanks,

Johnny



--
Paul


Re: Awards Program

Johnny
 

Hi all,

I'd love be a part of an awards program!

Let me know if I can help!  I could volunteer 2-4 hours a week if needed to help.

Love the ParkRX idea!  My wife and I are avid hikers.

Thanks,

Johnny


Re: Awards Program

Gary DeBock
 

On Thu, May 27, 2021 at 12:45 AM, Jorge Garzón wrote:
The ULR Group awards, as it is now, is a real gem, with beautiful classic designs and challenges to be beaten. I am awaiting to prepare the first awards and maybe we could first issue the two Ross DX Challenge awards we got, Paul Logan and me, at the end of year 2020. That interesting exercise was, in a way, what allowed to spread this fascinating side of DXing aroud here. 
Thanks Jorge,

The original ULR group Awards program was indeed a real gem, and it was extremely popular. In fact. it was so popular that the demand for the Award Certificates eventually overwhelmed the two volunteers.

Your generous offer to administer a European Awards Program is greatly appreciated, and thank you for your comment on the original Award Certificates! In the ULR-DXing community, the demand has always been for awards honoring long range DXing accomplishments-- especially transoceanic or transcontinental DXing receptions. The State and Province awards here in North America were also extremely popular.

Gary DeBock (in Puyallup, WA, USA)



Re: Awards Program

Paul Blundell
 

All really good points and I am not suggesting in any way that we try to be just like amateurs but instead have something we can all work towards. 

Paul

On Thu, 27 May 2021, 17:45 Jorge Garzón via groups.io, <iberiaDX=yahoo.com@groups.io> wrote:
It's true that Ham world gives much importance to awards and certificates. Almost 100% of them are issued by National Ham Clubs (ARRL, URE,...) or radio clubs. Something allowing the credibility of these documents is that they are issued to somebody holding a Call. My name is Jorge but I get an IOTA award to EB7EFA (my ham call). 

SWLers used to work awards when 'diexism' was in its golden years with powerful DXing Clubs that now are dismantled or survive as just e-bulletins or e-groups like us. Personal social interaction has been an important rol with awards and most of the times were given in meetings, or in the Club facilities, etc... 

I am officially EA1036-swl. This is my International SWL call. This can be asked here: http://swarl.org/ but it is mainly focused to ham contests, but also widely used in SW listening. That's important as Radioamateur world is still important as they feed corporativism and interaction with authorities, these giving rules to properly use the radioelectric spectrum. Unfortunately, despite e-bulletins or e-groups, DXers are mainly solitary people when listening. 

Transmitting a wave involves minimal tech skills. When a SOTA, or IOTA grid is activate, requires to erect an aerial, test it, adjust the SWR and balance the system to be heard by somebody. Getting the place is itself a challenge and be heard away it is also, and be heard by many is again a challenge. That's why DXing awards include a real challenge (number of countries, numbers of stations heards, counties or ### stations in a given time). But getting the same signals from different places is probably not as stations can be widely heard with a pocket portable. It is easy to listen to MW stations every season so not a challenge anymore. Regarding this, and working f. i. FM band, the challenge wouldn't be listen to many stations from a summit, but listen to the same stations from the bottom of the valley and test better aerials to get the better when propagation arrives. 

I also feel that NA and maybe Oz are more on getting awards than here in the Old World. People has found other means to show what they get (FB, Whatt'sApp, Instagram forums and so on...). 

The ULR Group awards, as it is now, is a real gem, with beautiful classic designs and challenges to be beaten. I am awaiting to prepare the first awards and maybe we could first issue the two Ross DX Challenge awards we got, Paul Logan and me, at the end of year 2020. That interesting exercise was, in a way, what allowed to spread this fascinating side of DXing aroud here. 

Sorry if you find some typo, but am writing on a mobile screen, too small in my opinion! 

Saludos


El jue., may. 27, 2021 a 2:08, Paul Blundell
<tanger32au@...> escribió:
Thanks for all the replies.

The below is something I have started in the past but never got off the ground, do you think this might make a good start? The name and details of it are all "up in the air" so I would welcome any and all feedback.

"ParkRXing is an awards program for anybody interested in the radio hobby, which encourages portable operation in parks and similar areas.

 

ParkRXing has been designed to make participation possible for anybody interested in the radio hobby. The rules are very simple and the awards have been designed to be achievable. The purpose is to encourage portable operation in parks and other similar locations, making the radio hobby more public and allow radio hobbyists to enjoy the great outdoors.

 

How do I start?

Get out in a local park with your radios and log what you hear, it really is that simple. A log file is available for download on this site.

 

Rules:

These rules are simple and have been designed to enhance the enjoyment of this awards program and ensure fairness.

 

1) All ParkRXing activity must take part in a public park, lookout, beach, mountain top or other such public location. All equipment must be portable and carried by the participant to their operating location.

 

2) No ParkRXing activity is permitted on private property for award purposes.

 

3) 5/10/15 rule:

- You must walk a minimum of 5 metres from any motorised mode of transport for a valid ParkRXing activity.

- You must log a minimum of 10 frequencies for a valid ParkRXing activity.

- You must remain in your location for a minimum of 15 minutes for a valid ParkRXing activity.

 

4) All frequencies must carry voice traffic. Data / paging frequencies are not permitted for award purposes.

 

5) All HF/VHF/UHF frequency bands are all permitted for award purposes.

 

6) Each location may only be counted once in a 48 hour period for award purposes.

 

7) Each frequency may only be counted once per location per ParkRXing activity.

 

8) All decisions of the ParkRXing administrator are final

 

Scoring:

Each activity counts for 1 point, bonus points are awarded for the first ParkRXing activity at each location (to encourage ParkRXing activity from different locations.) This adds 5 points to your tally.

 

Logging Process:

Below is an example of a valid log.

 

Awards:

Certificates will be emailed to all participants on the receipt of a valid log for the achievement levels below:

10 Activities

25 Activities

50 Activities

100 Activities" 


On Wed, May 26, 2021 at 10:17 PM Harold Cheetham via groups.io <hcheetham=yahoo.com@groups.io> wrote:
I think an awards program would be great. Like you said ham radio has all kinds of different awards so why shouldn't we. It might as you said help to get more people in the hobby. Will offer my help in any way I can.

Harold Cheetham




On Wednesday, May 26, 2021, 08:02:59 AM EDT, Paul Blundell <tanger32au@...> wrote:


Thanks for the information Gary. I was thinking something along the lines of the SOTA program which is very popular in the amateur radio world.

As you said, we need to decide on what awards we want to offer, this is the main thing I am looking for feedback on.

Paul

On Wed, 26 May 2021, 19:20 Gary DeBock via groups.io, <D1028Gary=aol.com@groups.io> wrote:
On Wed, May 26, 2021 at 12:09 AM, Jorge Garzón wrote:
Hi Paul, 
Gary was trying to activate this some time ago and I offered myself as a volunteer for that. Perhaps he could refresh the steps we made! 
73!
Hello Jorge and Paul,

As most of you know, the original Ultralight Radio Awards program has been inactive for quite a few years due to a lack of volunteers. Previously we had a list of categories (U.S. States, Canadian Provinces, Graveyard Frequency Catches, etc.) which qualified for Award Certificates, and each category had certain levels of accomplishment (10 States, 20 States, etc.).

After John Bryant's accident in February of 2010 I volunteered to do the processing of the Award Certificates, which is probably the most time-consuming volunteer position, requiring Adobe Photoshop software skill, and enough free time to draft multiple certificates. As is typical in any volunteer position, occasionally there will be complaints from certain individuals wondering why their Award Certificates are not received as soon as they would like to receive them. Since I was already pretty much "maxed out" on hobby time around 2013, there really wasn't any option for me to devote more time to process the Award Certificates, despite a steadily increasing demand for them. In addition, my long time Ultralight Radio collaborator Rob Ross was reviewing the applications prior to sending them to me, and he and I both agreed that certain individuals were making it tough for us by requesting multiple certificates in each category, despite the increasing demand by all-new applicants. With well over 1,000 members in the group our volunteer efforts seemed to be taking up more and more of our free time, and the situation reached the point where it couldn't continue. As such, the program went into limbo around 2014.

For a new Ultralight Awards Program to kick off, there would first need to be a consensus on which Award Certificates to offer, and after that, at least two volunteers with plenty of free time (one for reviewing the applications, and the other for processing the Award Certificates with the Adobe Photoshop software). Jorge and I discussed having a separate Awards Program for Europe and North America, and of course if there are volunteers in other areas such as Australia, South America or Japan, those areas can also have their own separate awards.

They key point in planning for a new Awards Program is to have qualified volunteers. The second key point is to respect the volunteer work that is done, because those guys are using their own free time to perform a free service for you. Unfortunately, I don't currently have the free time to volunteer for the North American Awards Program, but I've already provided Jorge with several sample Award Certificates, and would be happy to provide them to any other volunteer for new Awards Programs in other continents. Since the DXing challenges are different in each continent, my recommendation would be for each separate continent to determine which Award Certificates to offer-- after they have enough qualified volunteers to start off off their own program.

73, Gary DeBock (in Puyallup, WA, USA)
Ultralight Radio Group Co-Founder

  



--
Paul

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