BC Band Rx ant advice sought

[KA1ZGC]

I know this sort of question has come up in the past, but I'm looking for something specific, here.

Problem: I'm a Red Sox fan (no, that's not the problem part) and I have lousy reception of Sox games on WEEI (formerly WHDH) in my office station in Framingham, MA. WEEI is on 850 kHz, 50kW omni just outside of Boston, for what that's worth.

The station in my office is a Kenmore TS-430S feeding a flat-top dipole which is roughly 50 feet total length, broadside slightly west of north, and tuned by a homebrew parallel-tune matching network. No matter how I arrange the primary or secondary taps on the tuner, I get very little signal on 850 kHz. No, that doesn't suprise me, either.

I'm thinking my best bet would be some kind of helical ant, preferably without a ferrite core, but I've never done much with helicals. Considering that I'm interested in one frequency, and one frequency only, I don't mind the inherent high-Q of such a design, but I'm curious about some of the properties involved. For example:

Can such an ant be balanced-fed, or would I be stuck with a single-ended design, and are there advantages/disadvantages with either scheme?

Should I even bother trying to design such an ant to present an impedance that a parallel-tuned circuit would be happy with, or just shoot for 50 ohms unbalanced and feed it straight to the rig?

Are there other BC Rx ants besides helicals that present a relatively small form factor with similar results?

Should I try to load the existing diplole's feedpoints to unbalance the ant into some sort of end-fire setup, since the station is off the east end of the dipole?

Or am I just missing something even more obvious and simple?

Any thoughts, guys?

Tnx in advance,

--Thom
Killer Agony One Zipper Got Caught

[w3jn]

Try connecting the coass directly to the antenna terminal of the rig, and leave the shield shell unconnected.  In my experience you don't hafta have this matched well, just good coupling to the antenna (which the tuner is preventing) oughta do the trick.

The tuner's acting as a bandpass filter, and keeping that Fine Business MF from getting to the rig.

73 John

[flintstone mop]

Hi Tom,
I'm sure the others here will have many thoughts. There's a guy in Austrailia that makes tuned loop antennas that you can inductively coulple to your radio's loop ant OR connect directly via BNC or PL259 to your rig.
I'm ordering one his loops for the 160M band. He can modify the pre-amp for on or off or reduced gain.
Here's some info from an email to me:
Yes Fred, it is a tunable system, all but the single station loops I make are
tunable, there are no broadband antennas in our range, I consider response and
performance the as the leading specifications, and Hi-Q gives great results...

The Preamp cannot be bypassed, however I can give you a low and high gain
setting on the 3 position toggle switch, (centre off) no extra charge.

Qty 1x Modified Tropics Shortwave loop, to become a Dedicated 160m tunable
shielded magnetic loop, an indoor unit that will tune 1600 to 2000 KHz
approximately, comes with BNC to cable and DC power lead and external 9volt
battery holder

Let me know what you want on the other end of the BNC cable, a BNC or a PL-259

pkloops@bigpond.net.au


FRED YUP.......spend that money!!!!

[KE1GF]

I was thinking of a loop also, but one came to my mind the most... I don't know much about these but how about a Magnetic Loop?

[KA1ZGC]

Try connecting the coass directly to the antenna terminal of the rig, and leave the shield shell unconnected.  In my experience you don't hafta have this matched well, just good coupling to the antenna (which the tuner is preventing) oughta do the trick.

The tuner's acting as a bandpass filter, and keeping that Fine Business MF from getting to the rig.

Hmm... that's plausible, but the ant itself is fed by that cheap plastic 420 ohm ladder-line crap. The tuner is unbalanced in, balanced out. As it stands, I'm already bypassing the impedance transformer, maybe I should bypass the output tuning cap as well and get true DC coupling to the ant. Or, maybe I should just jam one leg into the center of the PL259 and see how that works...

I was thinking of a loop also, but one came to my mind the most... I don't know much about these but how about a Magnetic Loop?

Dunno... I don't know much about them, either, but I can certainly research it.

There's a guy in Austrailia that makes tuned loop antennas that you can inductively coulple to your radio's loop ant OR connect directly via BNC or PL259 to your rig.

I'll have to check that out, too... tnx fer the info, guys!

--Thom
Kerolene Apparatus One Zooming Golf Cart

[wavebourn]

Thom;
you may build something similar:

http://www.wavebourn.com/forum/viewtopic.php?t=194

Numbers of turns of both antenna loop and plate col are counter-proportional of frequency.

[2ZE]

Sure that the Kenwood doesn't have a bc band attenuator? Most kenmore's have a 20 db pad switched in when the rig tunes to the bcast band.

[w3jn]

Yeah, just jam one end of the balanced line into the ant jack.  Works on a Sunair milspec transciever I've been working on lately.  I don't see any reason to mess with loops, etc., unless you've got really bad noise or adjacent/on channel interference.

73 John

[wavebourn]

Yeah, just jam one end of the balanced line into the ant jack.  Works on a Sunair milspec transciever I've been working on lately.  I don't see any reason to mess with loops, etc., unless you've got really bad noise or adjacent/on channel interference.

73 John

What if a loop+attenuator?

A loop coil + breadslicer + 1-FET source follower loaded on a split resistor load to attenuate.

[KA1ZGC]

Thom;
you may build something similar:

http://www.wavebourn.com/forum/viewtopic.php?t=194

Numbers of turns of both antenna loop and plate col are counter-proportional of frequency.

Hey there, Tolly!

Well, that's quite the project, but it really shouldn't be necessary for what I'm trying to acheive. In this case, the transmitter is a 50 kilowatt omnidirectional station within 50 miles of my receiver. I should be able to hear them in my fillings! If I'm going to go that far, I might as well say "screw the Kenwood" and build a dedicated receiver from scratch.

Not that the active antenna isn't a sexy little unit, though!  

Sure that the Kenwood doesn't have a bc band attenuator? Most kenmore's have a 20 db pad switched in when the rig tunes to the bcast band.

  DOH!

Damn, I never even thought of that! I'll have to dig out the schematic when I get home... thanks for pointing that out! I was hoping for something simple and obvious, and that could be it! 20dB would definately put me back in the right ballpark (pun not intentional).

Thanks for all the input, guys! I gotta get back to work now, but I'll be listening on the outside speaker!  

--Thom
Keep Away One Zorched Ground Conductor

[WA1GFZ]

Tom,
Try series tuning the feeders or connect it as a T.

[W1DAN]

Hi Thom:

Good question!

WEEI is located in Needham and is a three tower directional signal. My guess is there is a null where you are listening. See Fybush's page here:

http://www.fybush.com/sites/2004/site-040604.html

I like Ferrite loops.

I have built a ferrite loop with preamp (copied form the old McKay Dymek DA-5) with good results. you can use a ferrite rod from Amidon.

http://www.amidoncorp.com/aai_ferriterods.htm

Kiwa makes an indoor loop:

http://www.kiwa.com/kiwaloop.html

Here is a page with general loop info:

http://www.frontiernet.net/~jadale/Loop.htm

Also in your neighborhood 1200 (WKOX) and 890 (??) are strong, and may overload your front end.

73
Dan
W1DAN

[KA1ZGC]

Hi Thom:

Good question!

WEEI is located in Needham and is a three tower directional signal. My guess is there is a null where you are listening. See Fybush's page here:

Already seen it.

It's a three tower array, but it's omni by day and east pattern by night. That's what the phasor shack is for. I have poor reception in broad daylight when they're in omni pattern, so a null isn't the issue in this particular case.

I like Ferrite loops.

I have built a ferrite loop with preamp (copied form the old McKay Dymek DA-5) with good results. you can use a ferrite rod from Amidon.

http://www.amidoncorp.com/aai_ferriterods.htm

I won't rule it out completely, but I'm trying to avoid ferrite ants if I can.

Kiwa makes an indoor loop:

http://www.kiwa.com/kiwaloop.html

Here is a page with general loop info:

http://www.frontiernet.net/~jadale/Loop.htm

Also in your neighborhood 1200 (WKOX) and 890 (??) are strong, and may overload your front end.

They don't bother my car radio, so hopefully the Kenmore won't experience anything I can't work around.

Tnx, I'll check out the loop ants.

--Thom
Kraft Advertisement One Zesty Grated Cheese

[flintstone mop]

Hi Guys,
The email address below is a VK HAM in Austrailia that makes tuned magentic shielded loops for half the price of the Palomar stuff.

 PALOMAR Prices:
Palomar is $130 for the base unit and the tuned plug-ins for various freqs ranges are $130 ea.


Paul
VK3KHZ

pkloops@bigpond.net.au

You can work with this guy.

Have a nice weekend
Fred

[KA1ZGC]

It's a three tower array, but it's omni by day and east pattern by night.

Whoops, I mis-spoke, there. It's semi-cardioid by day and cardioid by night.

Daytime pattern:
http://www.fcc.gov/ftp/Bureaus/MB/Databases/AM_DA_patterns/305498-3017.pdf

Nighttime pattern:
http://www.fcc.gov/ftp/Bureaus/MB/Databases/AM_DA_patterns/305498-3018.pdf

General license info:
http://www.fcc.gov/fcc-bin/amq?list=0&hpat=2&facid=1912

My bad.

--Thom
Killer Album One Zappa's Greatest Compositions

[wavebourn]

flintstone mop,
transistor amp in his tuned magnetic loop will be easily overloaded causing additional intermods.

[W1DAN]

Thom:

Thanks for posting the antenna patterns.

Looks like a null to the west?

Also, on my Ferrite loop antenna, I have not noticed the loop preamp overloading, but under certain situations My Yaesu FRG-7700 will overload (i.e. aimed and tuned to 1200 (WKOX) with all gains full on.

As usual a passive loop will not have that problem.

Dan

[Ed KB1HVS]

Thom. Maybe you could try to tune in to WBOQ 104.9FM. They simulcast the Sox games and maybe if conditions are right you might be able to hear them I live about 4 miles NE  from the transmitter so its no prob for me

[W1JS]

Hey Thom,

You got a medium wave band dx'er nearby in Billerica and he is an original member of the "75 meter gang". 

Mark's, WA1ION, web page is here:

http://www.qsl.net/wa1ion/

Check it out.  Mark is quite the expert on tuned circuits and antennas for medium wave.

[WBear2GCR]

Watson, my dear Doctor Watson, we must first analyze the evidence before we snatch the purp!!

So, the question is, how does it come in on the CAR RADIO???   
How about some one else's car radio?

(double vector on the issue)

Clearly, if it sux on the car radio, then there is a problem for sure... if not, then there is an ant problem! 

It may be heresy, but are the games streamed on the 'net??

         _-_-wBear2gcr

[Ed KB1HVS]

Just in case... FYI



2006 Red Sox Radio Network Affiliates
The Boston Red Sox radio network is comprised of 68 stations (49 AM, 19 FM) in the 6 New England states. For the 12th year, the flagship station is Boston's WEEI 850 AM. The announcers are play-by-play man Joe Castiglione, in his 24th year with the Red Sox, and color commentator Jerry Trupiano, with 14 years on the job.
If you live outside of the network coverage area, you can listen to every game over the Internet for just a $14.95 fee. To sign up visit mlb.com.



 
Massachusetts

Beverly/Gloucester WBOQ 104.9 FM
Boston WEEI  850 AM
Fall River WSAR 1480 AM
Fitchburg WEIM 1280 AM
Greenfield WHMQ 1240 AM
Milford WMRC 1490 AM
New Bedford WBSM 1420 AM
North Adams WNAW 1230 AM
North Hampton WHMP 1400 AM
Pittsfield WBEC 1420 AM
Springfield WHYN  560 AM
West Yarmouth WXTK  95.1 FM
Worcester WTAG  580 AM
Rhode Island
Providence WEEI 103.7 FM
New
 Hampshire


Berlin WMOU 1230 AM
Concord/Hillsboro WTPL 107.7 FM
Franklin WFTN 1240 AM
Hanover/Lebanon WTSL 1400 AM
Keene WKBK 1290 AM
Laconia WLNH 1490 AM
Littleton WLTN 1400 AM
Manchester WGIR  610 AM
Nashua WSNH  900 AM
Newport WNTK 1020 AM
New London WNTK  99.7 FM
Plymouth WPNH 1300 AM
Portsmouth WGIP 1540 AM
Rochester WGIN  930 AM
Wolfeboro WASR 1420 AM
Connecticut

Greenwich WGCH 1490 AM
Hamden WQUN 1220 AM
Hartford WTIC 1080 AM
New London WXLM 104.7 FM
Putnam WINY 1350 AM
Willimantic WILI 1400 AM
Vermont
Bennington WBTN 1370 AM
Brattleboro WKVT 1490 AM
Burlington WJOY 1230 AM
Middlebury WFAD 1490 AM
Morrisville WLVB  93.9 FM
Newport WIKE 1490 AM
Rutland WSYB 1380 AM
Springfield WNBX 1480 AM
St. Albans WRSA 1420 AM
St. Johnsbury WSTJ 1340 AM
Warren WDEV  96.1 FM
Waterbury WDEV  550 AM
Maine

Augusta/Gardiner WFAU 1280 AM
Bangor WZON  620 AM
Biddeford WVAE 1400 AM
Boothbay Harbor/Camden WCME  96.7 FM
Brunswick WJJB  900 AM
Calais WQDY  92.7 FM
Dover/Foxcroft WDME 103.1 FM
Ellsworth WDEA 1370 AM
Farmington WKTJ  99.3 FM
Houlton WHOU 100.1 FM
Machais WALZ  95.3 FM
Madison WIGY  97.5 FM
Mexico WTBM 100.7 FM
Millinocket WSYY 1240 AM
Norway WOXO  92.7 FM
Portland WLOB 1310 AM
Portland/Westbrook WJAE 1440 AM
Presque Isle WEGP 1390 AM
Rockland WRKD 1450 AM
Rumford WLOB  96.3 FM
Topsham WJJB  95.5 FM

[WBear2GCR]

       





       Go Yanquis!?[/b]













Sorry, couldn't resist...

           WBear2GCR

[2ZE]

Thom,
I had to tear into my TS850S for repair of my RF board this week
The 850 is pretty similar to the 430/440s as far as RF and IF. If you dig into your RF board, you'll find a set of small inductors that are in a row towards the RF amplifier for rx. These should be labeled as to what freq. they are setup for. These are the bandpass filters for each band. You should find a set for the broadcash band ( labeled like .5 - 1.6 or similar). There should be a set of solder pads for a jumper. All you have to do is install a jumper whioch bypasses the circuit for the 24Db attaenuator.
A service manual would be nice. I Googled my service manual and came up with several copies, I'm sure the 430 would be easy to locate.
Good luck.

Mike

[w3jn]

So, did using your existing antenner directly work, Thom 

[KA1ZGC]

Watson, my dear Doctor Watson, we must first analyze the evidence before we snatch the purp!!

So, the question is, how does it come in on the CAR RADIO???   

Full strap, Q5, solid copy, OM.

Over!

Clearly, if it sux on the car radio, then there is a problem for sure... if not, then there is an ant problem! 

BINGO!! Tell him what he wins, Johnny!

I was beginning to think that nobody understood that I was looking for a better BC Rx ant because the ant I'm using sucks on the BC band! Thank you for restoring my faith!

It may be heresy, but are the games streamed on the 'net??

They are, but I shouldn't have to pay for something that is already permeating the air around me free of charge.

I Googled my service manual and came up with several copies, I'm sure the 430 would be easy to locate.
Good luck.

This rig came with one. The previous owner was a member of a club I belong to, and as a service to widow(er)s we liquidate shacks of members who become silent keys and turn the proceeds over to the estate. This guy took great care of the rig and already had the service manual, so I'm all set in that department.

So, did using your existing antenner directly work, Thom

Haven't tried yet. Watched the games on the toob this weekend (and I'm glad I did), so it's been on the back burner. I'll try it out fairly soon and let you know.

--Thom
Kilimanjaro Africa One Zulu Goat Cheese