Ramsey Electronics Radio Antenna LPY2 User Guide

THE ‘LOGI’  
LOG PERIODIC  
ANTENNA  
Ramsey Electronics Model No.  
LPY2  
Constructed on rugged FR-4 material, it requires no tuning and  
has no fragile antenna elements to break or twist! Covers the  
entire 900 to over 2,500 MHz frequency range.  
Why settle for any old antenna… this little baby “compresses”  
the signal into a powerful beam that is 4 times more powerful in  
the direction you desire!  
Easy hookup to your Receiver or Transmitter  
Small thin size with excellent broadband performance  
Solid 6 dB gain from 900 to over 2,000 MHz!  
VSWR less than 2:1 - great for transmitters up to 10 Watts!  
Easily mounted by itself or makes a great feed for reflector  
dishes  
Construction ideas for a wideband corner reflector and a  
‘grid’ reflector dish are covered in the manual!  
Very directional - ideal for point-to-point links  
 
Ramsey Publication No. MLPY2  
Price $5.00  
KIT ASSEMBLY  
AND INSTRUCTION MANUAL FOR  
Logi  
LOG PERIODIC  
ANTENNA  
TABLE OF CONTENTS  
Introduction.................................4  
Antenna Description ...................4  
Standard Hook-up ......................5  
Low Frequency Modification .......7  
Building a Corner Reflector.........7  
Building a Reflector Grid.............9  
LPY2 Return Loss Plot ...............10  
Return Loss vs. VSWR Chart .....10  
Warranty.....................................11  
RAMSEY ELECTRONICS, INC.  
590 Fishers Station Drive  
Victor, New York 14564  
Phone (585) 924-4560  
Fax (585) 924-4555  
LPY2 3  
 
INTRODUCTION  
This small log periodic antenna, which we call the ‘Logi’, is ideal for getting the  
maximum performance out of any UHF to low frequency microwave wireless  
system. Its directional properties “compresses” the signal into a powerful beam  
that is 4 times more powerful in the desired direction. It is the ideal antenna for  
scanners, wireless LANs, and other wireless devices. Its directional properties  
make it exceptionally well suited for point-to-point links! The units small size  
and wide bandwidth also make it ideal for feeding reflector antennas, such as  
the easily constructed corner reflector or grid that are discussed later in the  
manual.  
ANTENNA DESCRIPTION  
To start with, what is a log periodic antenna? The seeming simplicity of the log  
periodic antenna belies the remarkable features of the design. It uses a  
common transmission line to alternately feed a group of 1/2 λ dipoles that are  
strung together. These antennas together display excellent radiation qualities  
over a wide range of frequencies as well as relatively uniform input impedances  
and good VSWR characteristics. While the log periodic design has been  
around since the late 1950’s it has now been discovered to be at the cutting  
edge of antenna development.  
Looking at the physical layout of a  
log periodic antenna, one would see  
that it is comprised of multiple  
elements working together to provide  
a wide bandwidth of usable  
frequencies. The active (radiating or  
receiving radiation) portion of the  
antenna effectively shifts with  
Feed  
Point  
frequency as one stage becomes  
‘more resonant’ than the next. The  
lowest operating frequency is  
determined by the longest element  
and the highest operating frequency  
is set by the shortest element. As the frequency of the transmission (or  
reception) increases, the active region of the antenna shifts forward to the  
shorter 1/2 λ dipole elements or vice versa as the frequency decreases.  
Obviously then the ‘secret’ for proper operation must lie in the length and  
spacing of the antenna elements. These and other factors must be carefully  
chosen to cover the desired frequency range for the antennas’ application.  
Instead of forcing you to figure out all the math and spend hours experimenting,  
the creation of the Logi antenna (for frequencies between 900 and 2600 MHz)  
comes to the rescue!  
LPY2 4  
 
STANDARD HOOK-UP  
Normal applications are well suited by the default performance of the unit  
without the need for cumbersome reflective elements. The standard wiring  
configuration is simply to use the Logi as the complete antenna and merely add  
a means of connection for your radio. The easiest method to interface your  
antenna and radio is through the use of a coaxial cable with a pre-mounted  
connector. Standard RG-58 and a BNC connector are often used by ‘scanner  
buffs’ to quickly and easily monitor the airwaves. Other types of coaxial cable  
such as RG-142, .141 and .085 semi-rigid will also provide you with a good low  
loss connection as well as excellent high frequency characteristics.  
Let’s take a look at the circuit board for a moment to  
become more familiar with its layout. The bottom side  
Via  
Bottom  
Top  
is the ‘ground’ connection and is labeled with the  
designers call sign “WA5VJB”. Notice that the via (the  
small plated through hole) near the narrow front of the  
board is not directly connected to the center trace on  
the bottom side. It is directly connect on the top side  
however.  
Bottom View of the LPY2 Logi Antenna  
Time to start playing! Interface  
the other end of the coax feed  
with your radio and enjoy the  
benefits of a broadband  
directional antenna!  
4 1/4"  
7/16"  
1/16"  
LPY2 5  
 
LOGI LOW FREQUENCY MODIFICATION  
If your radio system requires DC isolation or you plan to use your Logi below  
900 MHz, the small connecting traces near the rear of the antenna should be  
cut. By removing these traces you can extend the effective frequency range  
down to 825 MHz. You will however  
wind up with some ‘lumps’ in the  
matching response on the high  
frequency end.  
Soldered Coax Positioning  
BUILDING A CORNER REFLECTOR  
Corner reflector antennas have long  
been used by the Military and Radio  
Amateurs for high forward gain  
applications like field data links. Using a  
properly sized 90° angle corner reflector  
will typically give you a 10 dB gain or  
higher over that of a stand alone dipole  
antenna. The construction of a traditional corner reflector is very simple. Two  
plates are connected at a 90° angle with a feed element, usually a dipole,  
positioned along the vertex at the angular focal point of the plates. The  
dimensions of the reflector plates are luckily not critical (within reason of  
course) and the frequency characteristics are much better than most other  
parasitic arrays with the same gain rating. One drawback of the normal corner  
reflector arrangement is the fact that the active (radiating or receiving) element  
is usually a narrow bandwidth dipole. In our case, we suggest using the  
‘broadband’ Logi as the feed element. This gives you the same corner reflector  
benefits but without the normal narrow bandwidth limitations!  
With the wealth of information available today on the Internet, countless articles  
and design schemes can be found covering the construction of corner  
reflectors. The main difference from the norm is the use of the Logi as the main  
element versus a simple dipole. The following diagram gives a few basic  
dimensions for an experimental corner  
reflector. The main points to key in on are  
Final Installation View  
the base reflector size and the element (the  
Logi) placement for proper broadband  
coverage.  
Different types of materials can be used to  
form the reflector plates. Any type of  
perforated aluminum or copper sheet will  
work well. Small holes in the material help  
to cut down on wind resistance. The overall  
reflector length and width sizes should be  
chosen to properly work at the lowest  
LPY2 6  
 
frequency you plan to use. In the case of the  
Logi, 900 MHz was used to calculate the  
dimensions. A gain of 10 dB can be obtained  
with a reflector side length of one wavelength. A  
two wavelength reflector can be used to achieve  
upwards of 12 dB gain! It just means you’ll have  
a bit more wind resistance to factor in.  
The positioning of the Logi as the active element  
must also take into account the frequencies  
you’ll be dealing with. Thankfully, the physical  
layout of the circuit board takes care of this for us automatically! The narrow  
front end of the board should be placed so that it points into the vertex of the  
reflector plates. Rotate the board so that it lines up directly with the seam  
created by the two plates. This allows one side of the Logi to collect (in  
receive mode) or emit (in transmit mode) the electromagnetic energy from one  
plate to one side of the active element. If the Logi is turned 90° so that it does  
not line up in parallel with the seam, the antenna will not function properly.  
The boom length that positions the Logi at the focal point of the reflector is  
also critical factor. This will require a bit of trial and error to get things just  
right. Use a piece of PVC pipe (1/2” to 7/8” will work well) with a slot cut in the  
end just big enough to wedge the entire Logi in place. The narrow front edge  
of the circuit board should be positioned between 1.5” to 3” from the seam  
formed by the two reflector plates. PVC couplers can be mounted in the vertex  
of the reflector to allow you to slide the boom in and out while testing. Once  
the optimal position of the Logi is set, tighten the coupler and your ready to go!  
BUILDING A REFLECTOR GRID  
Building a reflector grid antenna as a home-brew project is a little harder then  
the corner reflector. It would be very difficult to achieve the proper parabolic  
shape for the reflector by banging on an old BBQ grill! The best way to insure  
your antenna will function the way you want is to use a pre-fabricated dish.  
There are a few different dishes that are easy to get and very affordable. We  
experimented with the ISM19R and ISM24R and found that they work  
wonderfully with the Logi!  
Look at the how the Boss used a piece of PVC and a few couplers to form a  
boom. He cut a slot in one end of the PVC pipe to hold the Logi antenna in  
place. Then he used a nylon wire tie at the end of the boom to squeeze the  
slotted pipe like a vise! Wow!!! Simple to make and highly effective!  
If you plan to do the same, here is a quick shopping list:  
LPY2 7  
 
ˆ 1 Ramsey ISM19R or ISM24R (or equivalent)  
ˆ 1 16 1/2” piece of 1/2” PVC pipe  
ˆ 1 1/2” to 1” PVC coupler (non threaded)  
ˆ 1 3/4” to 1” PVC coupler (threaded on the male 3/4” side only)  
ˆ 1 can of PVC cement  
ˆ 3 4” minimum nylon wire ties  
10.0" -12.0"  
°
90 Corner Reflector  
12.0"  
Insert the Logi  
narrow end first.  
Cut a slot into  
the PVC boom.  
Logi front edge placed  
1.5" to 3" from vertex.  
LPY2 8  
 
LPY2 mounted on a Grid Reflector  
LPY2 mounting Boom for a Grid Reflector  
LPY2 9  
 
LPY2 RETURN LOSS PLOT  
RETURN LOSS VERSUS VSWR - CONVERSION CHART  
Return Loss VSWR  
(dB)  
Return Loss VSWR  
(dB)  
Return  
Loss (dB)  
VSWR  
1.0  
2.0  
3.0  
4.0  
5.0  
6.0  
7.0  
8.0  
9.0  
10.0  
17.391  
8.724  
5.848  
4.419  
3.570  
3.010  
2.615  
2.323  
2.100  
1.925  
11.0  
12.0  
13.0  
14.0  
15.0  
16.0  
17.0  
18.0  
19.0  
20.0  
1.785  
1.671  
1.577  
1.499  
1.433  
1.377  
1.329  
1.288  
1.253  
1.222  
21.0  
22.0  
23.0  
24.0  
25.0  
30.0  
35.0  
40.0  
50.0  
60.0  
1.196  
1.173  
1.152  
1.135  
1.119  
1.065  
1.036  
1.020  
1.006  
1.002  
The LPY2 offers exceptional wide band characteristics from 900 MHz to 2.6  
GHz and can be used as a Receive or Transmit (10 Watts max) antenna!  
Standard guidelines for antenna systems:  
Receiver Antenna Match >  
Transmitter Antenna Match > VSWR = 2.0 : 1.0 or better  
VSWR = 3.0 : 1.0 or better  
LPY2 10  
 
The Ramsey Kit Warranty  
Please read carefully BEFORE calling or writing in about your kit. Most problems can be  
solved without contacting the factory.  
Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too!  
All Ramsey kits will work if assembled properly. The very fact that your kit includes this new manual  
is your assurance that a team of knowledgeable people have field-tested several "copies" of this kit  
straight from the Ramsey Inventory. If you need help, please read through your manual carefully.  
All information required to properly build and test your kit is contained within the pages!  
1. DEFECTIVE PARTS: It's always easy to blame a part for a problem in your kit, Before you  
conclude that a part may be bad, thoroughly check your work. Today's semiconductors and passive  
components have reached incredibly high reliability levels, and it’s sad to say that our human  
construction skills have not! But on rare occasions a sour component can slip through. All our kit  
parts carry the Ramsey Electronics Warranty that they are free from defects for a full ninety (90)  
days from the date of purchase. Defective parts will be replaced promptly at our expense. If you  
suspect any part to be defective, please mail it to our factory for testing and replacement. Please  
send only the defective part(s), not the entire kit. The part(s) MUST be returned to us in suitable  
condition for testing. Please be aware that testing can usually determine if the part was truly  
defective or damaged by assembly or usage. Don't be afraid of telling us that you 'blew-it', we're all  
human and in most cases, replacement parts are very reasonably priced.  
2. MISSING PARTS: Before assuming a part value is incorrect, check the parts listing carefully to  
see if it is a critical value such as a specific coil or IC, or whether a RANGE of values is suitable  
(such as "100 to 500 uF"). Often times, common sense will solve a mysterious missing part  
problem. If you're missing five 10K ohm resistors and received five extra 1K resistors, you can  
pretty much be assured that the '1K ohm' resistors are actually the 'missing' 10 K parts ("Hum-m-m,  
I guess the 'red' band really does look orange!") Ramsey Electronics project kits are packed with  
pride in the USA. If you believe we packed an incorrect part or omitted a part clearly indicated in  
your assembly manual as supplied with the basic kit by Ramsey, please write or call us with  
information on the part you need and proof of kit purchase.  
3. FACTORY REPAIR OF ASSEMBLED KITS:  
To qualify for Ramsey Electronics factory repair, kits MUST:  
1. NOT be assembled with acid core solder or flux.  
2. NOT be modified in any manner.  
3. BE returned in fully-assembled form, not partially assembled.  
4. BE accompanied by the proper repair fee. No repair will be undertaken until we have received  
the MINIMUM repair fee (1/2 hour labor) of $25.00, or authorization to charge it to your  
credit card account.  
5. INCLUDE a description of the problem and legible return address. DO NOT send a separate  
letter; include all correspondence with the unit. Please do not include your own hardware  
such as non-Ramsey cabinets, knobs, cables, external battery packs and the like. Ramsey  
Electronics, Inc., reserves the right to refuse repair on ANY item in which we find excessive  
problems or damage due to construction methods. To assist customers in such situations,  
Ramsey Electronics, Inc., reserves the right to solve their needs on a case-by-case basis.  
The repair is $50.00 per hour, regardless of the cost of the kit. Please understand that our  
technicians are not volunteers and that set-up, testing, diagnosis, repair and repacking and  
paperwork can take nearly an hour of paid employee time on even a simple kit. Of course, if we find  
that a part was defective in manufacture, there will be no charge to repair your kit (But please  
realize that our technicians know the difference between a defective part and parts burned out or  
damaged through improper use or assembly).  
4. REFUNDS: You are given ten (10) days to examine our products. If you are not satisfied, you  
may return your unassembled kit with all the parts and instructions and proof of purchase to the  
factory for a full refund. The return package should be packed securely. Insurance is  
recommended. Please do not cause needless delays, read all information carefully.  
LPY2 11  
 
LPY2 LOG PERIODIC ANTENNA  
Quick Reference Page Guide  
Introduction ........................................................4  
Antenna Description...........................................4  
Standard Hook-up..............................................5  
Building a Corner Reflector ................................7  
Building a Reflector Grid ....................................9  
LPY2 Return Loss Plot.......................................10  
Warranty ............................................................11  
REQUIRED TOOLS  
Soldering Iron  
Ramsey WLC-100,  
Ramsey RTS12  
Ramsey RTS05  
Ramsey RTS04  
Thin Rosin Core Solder  
Needle Nose Pliers  
Small Diagonal Cutters  
<OR> Complete Soldering Tool Set RS64-2801  
ADDITIONAL SUGGESTED ITEMS  
Optivisor Magnifier Headband  
Holder for PC Board/Parts  
Desoldering Braid  
Ramsey OPMAG  
Ramsey RTS13,  
Ramsey RTS08  
TOTAL SOLDER POINTS  
Price: $5.00  
Ramsey Publication No. MLPY2  
Assembly and Instruction manual for:  
2
ESTIMATED ASSEMBLY  
TIME  
RAMSEY MODEL NO. LPY2  
Beginner ........... 1.00 hrs  
Intermediate...... .50 hrs  
Advanced.......... .25 hrs  
RAMSEY ELECTRONICS, INC.  
590 Fishers Station Drive  
Victor, New York 14564  
Phone (585) 924-4560  
Fax (585) 924-4555  
 

Radica Games Video Game Console 71023 User Guide
Radio Shack Portable Radio 12 521 User Guide
Rangemaster Cooktop U109948 04 User Guide
Rangemaster Ventilation Hood L1 400370 User Guide
RIDGID Vacuum Cleaner RV2400A User Guide
Samsung MP3 Player YP MT6 User Guide
Samsung Range FER300SB User Guide
Samsung Satellite TV System SIR S300W User Guide
Sanyo Battery Charger N 600AA User Guide
Sears Sewing Machine 385 User Guide