Sorry for the lateness of my comments. I would suggest
that anyone wanting a "crash course" on the construction
of delta loops read Doug DeMaw (W1FB) and Lee
Aurick's (W1SE) article titled "The Full Wave Delta Loop
At Low Height" in the October, 1984 issue of QST.
I have used delta loops for DX'ing on 40, 80 and 160
meters and constructed my loops exactly as per the
article. I used a length of 75 ohm coax as a matching sec-
tion (as discussed in the article) to "convert" the antenna's
impedance to the required 50 ohms.
I have always hung my loops with the apex at the top, for
the lowest angle of radiation (as discussed in the article).
For feeding, I simply used one of the bottom "corners"
for the feed-point. I DID NOT feed any of my loops "1/4
wavelength up from the bottom," as suggested by others.
I don't know if this would be of any added benefit; my
loops seemed to work just fine the way I fed them.
When first starting out my DX'ing on 40 meters, my loop
was a very competitive antenna in the pile-ups. That is,
until so many hams started putting up 2, 3 and 4-element
yagis for that band.
I started out DX'ing in 1982; after upgrading from Novice
to Advanced. I had worked a few DXCC entities as a
Novice - VE, KP4 and V7. These were worked with a
"coaxial inverted vee" antenna. Shortly after reading the
above-mentioned article, I constructed my first 40 meter
delta loop. The following DXCC entities were worked
with this type of antenna:
3B8, 3B9, 3C0, 3D2/F, 3D2/C, 3D2/R, 3DA0, 3X,
3Y0/B, 4J1, 4U/ITU, 4U/NY, 4X, 5H, 5N, 5T, 5V,
5W, 5Z, 6W, 6Y, 7Q, 7X, 8P, 8R, 9H, 9J, 9L, 9Q,
9Y, A3, C2, C3, C5, C6, CE, CE9, CE0/EI, CE0/JF,
CM, CN, CP, CT, CT3, CU, CX, CY0/SA, CY0/SP,
D4, DL, EA, EA6, EA8, EA9, EI, EL, ES, F, FG, FS,
FK, FM, FO0/CI, FO0/FP, FR/R, FT8W, FT8X, FT8Z,
FW, FY, G, GD, GJ, GM, GW, H44, HA, HB9, HB0,
HC, HC8, HH, HI, HK, HK0/SA, HP, HR, I, IS0, J3,
J5, J6, J7, J8, JA, K, KG4, KH1, KH4, KH5, KH5K,
KH6, KH8, KL7, KP1, KP2, KP4, KP5, LA, LU, LY,
LZ, OA, OH, OH0, ON, OX, OY, OZ, P4, PA, PJ2,
PJ5, PY, PY0/F, PY0/S, PY0/T, PZ, S0, S9, SM, SP,
SU, SV, SV9, T2, T32, T7, TA, TI, TI9, TK, TR, TU,
TZ, UA, UA9, UB, UC, UF, UG, V3, V4, V5, V7, VE,
VK, VK9L, VK9W, VP2E, VP2M, VP2V, VP5, VP9,
VR6, VU, XE, XF4, YB, YJ, YL, YN, YO, YS, YU,
YV, YV0, ZD8, ZF, ZK1/N, ZK2, ZK3, ZL, ZL7, ZL8,
ZP, ZS and the following deleted entities...OK, ST0,
ZS/PI and ZS/WB.
I am not trying to make myself look like a super DX'er;
only that delta loop antennas work very well. I still use a
delta loop on 80 meters (273 wkd / 270 cfmd) and also
used a delta loop on 160 (176 wkd / 174 cfmd).
I might also add that at one time, I had my 40 meter
delta loop mounted "inside" of the 80 meter loop and
saw no degradation of performance of either antenna. I
just wanted to share my experiences that I have had over
the years with delta loops and have been extremely
pleased with the results that I've obtained.
Good luck & good DX!
73 de Brad, N9EN @ Radio Free Roscoe (IL) [tm]...
----- Original Message -----
From: "Joe Giacobello" <firstname.lastname@example.org>
To: <Towertalk@contesting.com>; <email@example.com>
Sent: Wednesday, September 15, 2004 2:56 PM
Subject: [TowerTalk] Delta Loop Info and Opinions?
> I have just read the section in Low Band DXing on delta loops and was
> giving consideration to putting up concentric loops for 30 and 40M and
> hanging them by one of the apices from my 70 foot tower. Although I
> plan on modeling the setup and reading W4RNL's write-ups also, I do have
> several questions and would appreciate hearing from those of you who
> have practical experience with these antennas.
> * I presume that, as with quads, there should be no problem in using
> concentric delta loops?
> * ON4UN in his book recommends detuning the tower by running a wire
> down the side in series with a variable capacitor and tuning for
> minimum current with an RF current probe. However, it seems that
> this would only work for one of the bands, and you'd have to
> accept some interaction with the tower on at least one of the bands.
> * Does anyone have any experience with this detuning trick? Did you
> find that it was really necessary?
> * Do you have any suggestions for how to accomplish detuning for two
> bands? Two wires and two capacitors?
> * Does a crankup tower alter this detuning requirement in any way?
> I'd appreciate any info you folks out there can provide.
> 73, Joe
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> TowerTalk mailing list
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
TowerTalk mailing list