40m is more useful, so personally I'd choose that option.

You can build a wire dipole(s) or use a retuned CB antenna on the upper HF bands (including 10m) and it will be more efficient than a small loop.

Regards,

Martin

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If 40m is mandatory and u are involved in local EmComms use the 1788. I have a 1786 since 1995 and actually I have a single element delta loop on 10. I use the loop on 30 ... 12m, installed at H pol. But if comparing signals on 10, the delta loop is at least a "S unit" better. Both are at the same height above my home (~6m). Yes, they are vy sharp, and on the lower bands sometimes I need to readjust after a few hours. On contests is a bit inefficient due to frequent re-tune when changing band or even frequencies inside the same band.

I remember the manual / advertisements on late 90s where they say the 1786 should perform as a dipole at the same height on 30MHz and -6dB at 10MHz. At that time I consider the Isoloop as well.

73
Marcus PY2PLL = PY3CRX

40 meter is not mandatory. I guess my question is which is "nicer to have", 40 meters or 10 meters? I guess for me the question is is it worth rigging up a separate antenna for 10 meters to get the loop that goes to 40 - or just get the 10 to 30 meter loop version and be done with it.

40m hands down..10m hardly open, 40 always ( nearly) for local ish ragchews and if lucky dx..

A 10m antenna is so easy to make and hide..( use cb mobile whip,1/4w etc)

Simon

Hi, Jerry.?

Sorry I guess I misunderstood. As you talk abt EmComms 1st thing that came in my mind was: NVIS radiation patterns. And this prop mode is ok below 14MHz or so.

Anyway 10m is easy to solve as other fellows already proposed.

One last note, and may be this comment is shared by other manufacturers: on MFJ loop all joints are welded: butterfly capacitor plates, capacitor connection to the loop, etc. No screws and nuts to worry about. At least at the 1995 production =:D

Regards
Marcus

Em 28/09/2022 12:17, gfmucci via groups.io escreveu:

Jerry, I used a 1788, chose it over the 1786 because 40 is very active and 10 is under used. Seems I can hear many FT8 signals, tons of CB stations a bit lower and nothing at all on 10CW or SSB.?
GeorgeC W2DB

On Wed, Sep 28, 2022 at 11:12 AM, r388yh wrote:

FYI, this group is mainly for small receiving loops such as used for receiving VLF (3 to 30 kHz) LF (30 to 300 kHz) and MF (300 kHz to 3 MHz) frequencies.

That is news to me, and I'm the listowner.

From the group description:
This is your "HOW TO" Loop Antenna Forum to : Get Information, Plan, Design and Build Loop Antennas for both Radio Reception and Transmission. Air loops, magnetic loops, ferrite loops, shielded, unshielded, SLF to any frequency you can make a loop antenna for.
?
--
Steve Greenfield AE7HD

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Steve,

The broad scope of this listing is commendable and useful.? However, I have noticed many times it is difficult to determine what kind of loop the poster is talking about, which can lead to confusion or misunderstanding.? The list below provides many of the basic classifications of loop antennas – there may be others.? A well-conceived topic or thread title would certainly help, or just stepping back and trying to perceive how one’s posting might be interpreted by the readers before clicking on the send button.

Just at thought,

Dexter

·???????? Receiving or Transmitting – Despite their inherent low radiation resistance, loop antennas are sometimes adapted to transmitting.

·???????? Electrically Small or Large – For electrically small loops, the dimensions of the primary coil are much shorter than the wavelength being tuned, defined as less than or equal to l/10, where l is the wavelength of the incoming signal.

·???????? Resonant or Non-resonant – Resonant loops consist of a coil and variable capacitor which resonate over a band of frequencies to produce an alternating magnetic field having a high figure of merit or Q.

·???????? Passive or Active – For passive loops, there is no active amplification outside the receiver.

·???????? Air Core or Ferrite Core – For air core, the space between turns of the coil, notwithstanding any wire insulation, is air.? It relies on the number and the area of turns for its effective height, or ability to generate a voltage across its terminals.? This differs from a ferrite core coil, which due to its high magnetic permeability can focus or concentrate a larger area of magnetic field through the center of the coil, thus greatly minimizing the size of the coil.

·???????? Spiral or Solenoid – A spiral loop is sometimes referred to as a flat or ‘pancake’ loop; that is, the coil is wound in a single plane.? It differs from a solenoid loop which is wound cylindrically along the coil’s center axis; that is, a solenoid is three dimensional.

·???????? Local or Remote – A local loop antenna is intended to operate near the radio.? Some experimenters have used variable capacitance diodes, or, as they are variously known as a varicap diodes, varactor diodes, variable reactance diodes or tuning diodes.? These devices permit a remote resonant antenna to be tuned.

·???????? Transformer-Coupled or Directly-Coupled – For a transformer-coupled loop, there are two coils, which operate on the principle of a transformer.? The primary coil is the main receiving antenna, which, in resonance with the variable capacitor, produces an alternating magnetic field.? The secondary coil, which is shielded to normalize directional response, operates by mutual inductance, and, along with a transmission line, provides low-impedance input to the radio.? A directly-coupled loop can be connected directly between the antenna input and ground of the receiver and generally operates as a low-impedance input.

Being the OP of this thread, I was subsequently reminded that for "transmitting loops" I should have posted my question on the "Mag Loop" Group forum instead of to this Group.? However, my reference to MFJ-1786 and MFJ-1788 (the Subject line of Dexter's post) are well known models that I did not believe required further elaboration. Perhaps Dexter's post needed a new Subject heading such as "Suggestion to describe type of antenna" or some such rather than a continuation of the MFJ thread.

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Agree, but I was responding to the list owner's posting on this thread.? Gets complicated.

Dexter

Hi

Yes mag loop group is all about trx loops, HOWEVER the knowledge on here is supreme.. I see no issues with posts about mfj or whatever here..

Think about it..no one with real estate in middle of nowhere would use a loop of any kind..why would you?

So if using small active rx loops or tunable rx loops then one may well have experience on trx loops..I do..I have to due to my location..

Also original poster was quite clear in request..yes?

Just my 1penny worth..Simon g0zen

The 1788 covers 10-30 Mhz and the 1788 covers 7 Mhz to 21Mhz

John VE3IPS

Double check all solder joints as the QC can be? poor at MFJ

Can you believe the minimum wage in Mississippi is $7.25 an hour and congress wonders why there is such poverty??

On Tue, Oct 4, 2022 at 08:51 AM, John wrote:

The 1788 covers 10-30 Mhz and the 1788 covers 7 Mhz to 21Mhz

Should be?1786?covers 10-30 Mhz and the 1788 covers 7 Mhz to 21Mhz

John VE3IPS

Double check all solder joints as the QC can be? poor at MFJ

Can you believe the minimum wage in Mississippi is $7.25 an hour and congress wonders why there is such poverty??

I don't want to be forced to pay a guy to fix my loop antenna more than he is worth.

Steve, I apologize for giving an incorrect description of this group to the OP. I stand corrected! Thank you.

73, Joe K9LY