9:1 Wideband RF Transformer
For SWL Receiving

- Smooths the extreme impedance swings associated with end-fed antennas as they pass
through odd and even, multiple or sub-multiple, resonant points.
- Allows maximum signal energy transfer from antenna to 50 - 75 ohm feedline.
- Provides a continuous bleed of static electricity by DC shunting the antenna feed to ground.
- Rejects common-mode noise signals that are present on the coaxial shield, and keeps them
from entering the antenna feed line.
- Offers additional protection for sensitive solid state equipment from nearby lighting strikes,
by offering a high impedance to the high frequency components of the strike and DC
decoupling of induced voltages to the antenna feed line.
(Note that due to the unpredictable nature of lightning
and nearby strikes, no guarantees or performance claims for the transformer can be made. A direct lightning strike will likely destroy
this transformer, the antenna itself, and any/all equipment connected to the system.)
20KHz to 30+MHz (Flat from 50/100KHz 30MHz)
End-fed Antenna Transformers
T-5030-R & T-5030-P20
These transformers are built on a design that has been developed and refined from several
years of R&D, prototyping, and beta testing, to determine the best combination of transformer
core material (ferrite mix), winding configuration, inter-winding coupling, source impedance,
terminal impedance, and efficiency.

The basic design considerations for this model transformer are to provide:

1. A very flat transformation response from 100 KHz to 30+ MHz, and down to 20KHz with a
3-6dB loss (depending on feed impedance of antenna), which includes the LF (lofer and
NDB-nondirectional beacon band), MF (AM broadcast band), and HF (shortwave band).
2. A significant smoothing of impedance swings at non-resonant frequencies to more closely
match a 50 - 75 ohm load (or source) and provide maximum signal energy transfer.
3. A total broadband loss of less-than 0.5 - 1dB (3-6 dB loss at LF frequencies).
4. Absolutely minimal inter-winding capacitance.
5. Over-designed, heavy construction for long life and reliable weatherproof service.
6. Completely weather and environment proof against UV, ozone, moisture, salt, environmental
alkali and acids. Assembled with marine epoxy (encapsulated).
7. Common mode choke against RFI (electrostatic and electrodynamic), local pickup (acting as
an antenna to strong local signals), and neighborhood / household noise sources.
8. Isolation / shunt of DC static buildup currents.
Environmental resistance to corrosive and caustic elements, plus salt, ozone, and UV
Direct ground connection recommended (the correct way) at the feed point, but not required
for operation).
All components are marine epoxy encapsulated against weather and environmental damage.
Just solder 4 wires to your connectors of choice and add your own enclosure.
Photo of typical
T-5030-R Transformer module.
Connectors and hardware are NO LONGER supplied.
Due to so many requested assembT-5030-R
ly options with various connectors and
enclosures, we decided to offer ONLY the module and
reduce the price accordingly. You must supply all other
construction materials.

We request that you contact me (below) to indicate your interest in this product.
You are not obligated, in any way, to purchase this product, but your interest to purchase one is
important to our planning and scheduling. These are "batch made" and may be out of stock for as long
as 2-3 weeks. E-mail me to reserve one and I'll advise you of our inventory status.
We will not accept any funds until the product is available for immediate shipping.
I usually ship within 3 business days of payment via PayPal or check clearance.
Payments received via check through the postal service will be held for check clearance - usually 10 business days.

A note on the cost of this item:
The cost of the parts for these transformers has not been spared; they represent the bulk of the sales
price. The components are of the highest quality available. Very little allowance has been given for labor
costs, and any funds above and beyond the cost of parts will go toward maintaining this Web site.

Please send your intentions to buy, or interest in, the these Antenna Transformers
to me. You are
not obligated to purchase this item in any way - click here.
Once sold, only the owner of the transformer is responsible for its safe and proper installation and use. The maker or seller
assumes no responsibility for proper and safe installation and use. Damage, of any kind, including storm, lightning, and any other
hazards of Nature or accident, whether intentional or coincidental, are the sole liability and responsibility of the owner
No refunds, returns, or replacements will be honored unless the item fails to function as specified. The seller is not responsible for
lack of technical knowledge in installing or use of the item, damage incurred, or any other personal, material, or monetary liability.
The customer is expected to ask questions of the maker if in doubt as to proper installation and/or safe use, and to read and retain
any/all instruction materials.
Returns for refund must be in "as received", re-saleable, factory fresh condition and accompanied by all original paperwork,
packing, accessories, etc. Refund will not include postage/shipping charges.
Shipping damage must be claimed by the buyer and filed with the delivery carrier upon receipt of the item. The shipper assumes no
liability for shipping damage or any other damage beyond his control.
Erroneously referred to as a "balun" or "MLB", but more properly an "UNUN," this Ultra-Widebabd RF transformer will improve the
quality of signals from an end-fed, random wire, long wire, inverted "L", or Marconi type wire antenna.
Module Prices:

T-5030-R Receive only. Very Limited Quantity
$35.00, (Plus $5.00 shipping, USA)*

100KHz - 30+MHz. Lowfer, Medium Wave (AM broadcast band), Shortwave band.
(Down to 30 KHz response with 1/2 to 1 "S-Unit loss" depending on antenna impedance and other
conditional variables.)


T-5030-P20 Receive and Low power Transmit (QRP) (Average 20 Watts, depending on
VSWR mismatch)
$45.00, (Plus $5.00 shipping, USA)*

50KHz - 30+MHz. Lowfer, Medium Wave (AM broadcast band), Shortwave band.
(Down to 30 KHz response with 1/2 to 1 "S-Unit loss" depending on antenna impedance and other
conditional variables.)
I could use lesser-quality parts and lower the manufacturing costs of these items, but as with everything I have offered so far, I try to design to (or close to) MIL-SPEC
assembly and component standards, for quality of performance and operational durability. This design is exceptional and meets the qualifications that I would want for
my personal use. In fact, the very first unit is still in use, feeding a Marconi antenna to my
listening post. The same design is used in the RFP-1, with multiple taps to offer
36, 50, 75, 150, 300, 450, 600, and 1200 Ohms. The design criteria was simple:
minimal loss, wide bandwidth, and high saturation level.
I wish to thank all of my previous customers for their nice comments and feedback; it's appreciated.
If you want one of the 9:1 modules, (as shown), you are invited to e-mail me and I will advise payment and shipping schedule I normally do not stock these
transformers. They are made in small batches, so if you really want one, please contact me and I'll reserve one from the next batch.
Photos of typical
T-5030-P20 Transformer module.
Receive & 20-Watt Transmit.
We currently offer ONLY the module. You must supply all
other construction materials.
Note: This is not a current balun - it is a 9:1
impedance ratio transformer