• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

Box Loop Update

I just got a Kaito KA33 small indoor loop to start with, and it makes some difference on AM. 660-which used to be KIXI/KXPA with maximum overloading, is now a fair signal of KAPS Mount Vernon. Easily listenable.
1520 KKXA is so strong it pegs the S-meter from Snohomish.
I had 540 XESURF Tijuana last night at a slightly better signal strength.

-crainbebo
 
I made a wooden 4' loop with plans from the NRC years ago called The NRC Loop, I still have it but don't have the room to use it right now. It was made to be used with an RF amp but it seems to work OK without it. I also made a loop called the Wedge from NRC plans which worked well. They were both made to hook up directly to the radios, they have pick up loops consisting of about 2 turns of wire in line with the main body of the loop. They were made to tilt as well as to rotate so you could just about null any station into the noise that you wanted. I used 365 pf caps with them.
 
I've had some pretty decent catches with a simple Grundig AN200 loop. I have used it with a number of radios and it pulls in what they can't barefoot. I've never had much luck with connecting it to anything though, as it always seems to overload anything that way.
 
With a preamp or large loop, it's good to have a radio with an RF Gain Control. I have one setup where I have to turn the gain all the way down. Then if something is really weak, I turn it up a little if I can. The preamp I used with that is a modification of the one in "103 Simple Transistor Projects" by the late great Tom Kneitel.
 
Schroedingers Cat said:
With a preamp or large loop, it's good to have a radio with an RF Gain Control. I have one setup where I have to turn the gain all the way down. Then if something is really weak, I turn it up a little if I can. The preamp I used with that is a modification of the one in "103 Simple Transistor Projects" by the late great Tom Kneitel.
Click to expand...

I don't think I own a receiver without an RF gain control.
 
Back at Valpo Tech DE Wiggins had a big "diamond" loop in his office, connected to a fine boatanchor.
It was a square wooden frame, mounted upright diagonally.
It must have been about 2 feet on each side and also had a seperate coupling loop.

Back in the 80's, in an antique store, I found a ready-made loop from about 1925 that is a sort of a squashed diamond.
Think of a diamond-square, but being spueezed on the side to form vertical sections.
It requires less free room to spin. It's maybe 20 inches tall, and is an all wood frame.
/\
/ \
| |
| |
| |
\ /
\/
The outer loop when wound on this frame is about 8 inches deep. It fully tunes the AM brodcast band
when used with a 365 pf cap. I use a flat, "book" type Crosley cap right at the base of the loop.
A center post holds the frame and allows the loop to spin through 1 turn.
A smaller loop of about 5 turns is mounted on the centerpost on a subframe within the bigger loop, and the two ends of that feed to the radio.
The angle of coupling between the outer and inner loop is fully variable, so it's always been a lot of fun to
not just null other signals, but to truly be able to hear so MUCH more in every signal.
I've also passively coupled and phased the loop signal against a longwire signal for even better nulling.

Then there's the MFJ "noise cancelling" amp, feeding the loop and the longwire opposite each other.
Loops are too much fun and effective to not use.
 
The NRC FET loop is 4' on one side and balanced, you need an old boatanchor with balanced inputs to use it. I used it quite a bit with a Hammarlund HQ-180 years ago.
 
As of tonight, we have gotten eight turns of wire onto the antenna. Next step is the mount a surface for the variable capacitor.

-crainbebo
 
The box loop is finished! Highlights around 4:30PM

1700-Issaquah TIS went from nothing to a 35dbu, very good signal!
1670-KNRO Redding, CA went from threshold to 39dbu (1000w)

Unfortunately I do hear a LOT of 880 and 1150 bleed all over the band. East is the only direction to point. Nighttime is better (from 50kw-880/10kw-1150 to 10kw-880/6kw-1150). Anyway to help this? Or is the only option to go up in the Cascades? I live two miles from 880 and 1150.

-crainbebo
 
More to add

1610-WQBV569 Union Gap and about 14 other TIS stations (WOW!)
1630-KRND in splatter
1640-KDZR/KBJA PEGGING S-meter!
1650-Redmond TIS and likely Denver
1660-KTIQ/KXOL and English Christian program (Who?) Plus NOAA station from somewhere in Oregon (10 watts!)
1670-KNRO big
1690-KFSG big
1700-Issaquah TIS very listenable.

-crainbebo
 
crainbebo said:
The box loop is finished! Highlights around 4:30PM

1700-Issaquah TIS went from nothing to a 35dbu, very good signal!
1670-KNRO Redding, CA went from threshold to 39dbu (1000w)

Unfortunately I do hear a LOT of 880 and 1150 bleed all over the band. East is the only direction to point. Nighttime is better (from 50kw-880/10kw-1150 to 10kw-880/6kw-1150). Anyway to help this? Or is the only option to go up in the Cascades? I live two miles from 880 and 1150.

-crainbebo
Click to expand...


Wow. You have shown that a loop does work with skywave DXing too.

And I've never noticed a difference with my Terk loop.

Now, I'm more motivated to build one of my own.

And as far as the bleeding all over the entire band, there's nothing you can do.

I have the same thing happen during the day with WFLA and WHNZ only a couple miles away even without any loop.

There's a park a few miles to the east where it isn't an issue even with the loop.
 
crainbebo said:
More to add

1610-WQBV569 Union Gap and about 14 other TIS stations (WOW!)
1630-KRND in splatter
1640-KDZR/KBJA PEGGING S-meter!
1650-Redmond TIS and likely Denver
1660-KTIQ/KXOL and English Christian program (Who?) Plus NOAA station from somewhere in Oregon (10 watts!)
1670-KNRO big
1690-KFSG big
1700-Issaquah TIS very listenable.

-crainbebo
Click to expand...

I'll be interested to hear if you pick up those eastern blowtorches better than before.
 
1650 KFOX is really, really good tonight. Probably around S-8 or 9. Swapping with Redmond at times. KDIA did pop up on 1640 briefly, but for the most part KDZR is pegging the S-meter at probably 30 over! 1kw, 145 miles S. 1700 XEPE and the Issaquah TIS are very listenable, and I think there was another co-channel (The Little Station that Could-aka KVNS?)

More to note
The capacitor unfortunately starts heating up around 580 khz. 530 does not work. Cuba got away I guess :(
600 CJWW was very good tonight, probably also S8-9. Could listen to a bluegrass version of "Frosty the Snowman" and a CJWW ID clearly.
640 KFI was so strong it was taking over the KXPA spur on the G5. Probably 25 over 9.
I caught XESURF and CBK on 540. Maybe co-channels.
Lots of slop from KYIZ on 1610, but WQBV569 Union Gap (WSDOT) and Naval Kitsap from Bremerton (the emergency station) popped up.
CJYM and KKPZ had huge signals on 1330.
KSTP came in, although only poor-fair, on 1500. Maybe next time.

Putting the capacitor near 880, it turns into a 97dbu overload monster. 1150 is around 93dbu and 1540 around 89dbu. I will definitely AVOID those areas of the band!! Unless if I move somewhere far, far away...

-crainbebo
 
KB1OKL said:
I don't think I own a receiver without an RF gain control.
Click to expand...

I don't own a receiver *WITH* an RF gain control.

Crainbebo, have you tried combining the loop with a chain-link fence or with a utility pole ground wire?
Looks like WWL and WLS may still be a wee bit tough, though (especially getting full-fidelity C-Quam audio from WLS), based on what I'm reading. I would think it should be a bit easier than trying for WHAM here, though. I didn't attempt it due to the time of day, and didn't have the presence of mind to try for KERN or KSL. Also 909-BBC would have been tough (or rather impossible with my basic equipment, although I would hope a well-designed SDR like a Perseus could get full-fidelity audio from BBC in the evenings without any trace of splatter from KECR) due to proximity to 910-KECR's transmitter site.

So when you got 97 dBu on 880, it was actually starting to clip the audio, right? I bet you could get 98 dBu (pegging the meter), although to fine-tune it you might have to tune to its 3rd harmonic, 2640 on SW. Also I find that while sometimes spacing the radio from a loop can in most cases improve the signal, when boosting the strongest signal on the dial I find that putting the radio right on the loop gives the largest boost.
 
Actually I think I did have 98 dbu at times with the capacitor on the 880 frequency.

1180 should be interesting. I'm going to try all I can for Radio Rebelde Cuba. It was heard a few nights ago by a DXer about 10 mi S of me.

I've heard WWL and WLS here. WWL a couple times, WLS once.

I used the G5 on a utility pole one time, and many signals went from good to pegging the S-meter. 1630 KRND very strong (this was in Gresham, OR at the Hampton Inn).

-crainbebo
 
If you can disconnect the radio's pickup loop from the internal ferrite bar and just connect the external loop,
there should be a lot less of a problem rejecting nearby local powerhouses.

I've mostly used my tunable loop with a Collins 390 and a Philco 116-X.
Neither of them have internal antennas, and both provide for balanced or unbalanced inputs.

The idea of connecting a "wire" antenna to the loop or the pickup loop is a good one, it can improve rejection of an undesired
signal.
 
Daytime with the loop will only be used outside this area ONLY. Even pointing the loop's capacitor way past 1600, KXPA and KIXI bleed in everywhere.

-crainbebo
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom