This blog was created to share my projects, ideas, and experiences in amateur radio with other operators around the world who also enjoy this wonderful hobby.

Saturday, June 30, 2012

PL-259 Connector Installation on Belden 9913F

step 1

The first step is to make sure your coaxial cable end is properly cut and the cable is not dirty or corroded. You will know this when the coaxial outer cover is removed. If the shield is not bright and clean, cut the cable further inside until you find the braided shield wires shiny. When the coaxial cable is new, this inspection is not necesary. If the coax is old or has been used outside your shack, it is very important to check the coaxial. If it is corroded it won't take solder. In this example I am using Belden 9913F coaxial cable and the Amphenol  83-ISP-1050 Pl-259 connector.

step 2

Next, you will need to cut about one inch of the outer coaxial cable cover with a sharp knife. Use a coaxial stripping tool if you have one and be very careful not to cut the braid wires.

step 3

The next step is to cut the braid leaving about 3/8" of it trimmed with a  very sharp cable cutter or a small scissor. Trim the braid all the way around  to the proper lenght and make sure there are no wires left above the 3/8" mark.

step 4

Now you need to solder the braid all the way around with a good quality 60/40 rosin core solder. I use Radio Shack 60/40 rosin core .032" diameter (part number 64-009)  You also need a soldering iron, pencil type or a soldering station, 40 watts or higher. Avoid using soldering guns unless you have some experience soldering with them. They are more than 75 or probably 100 watts and excessive heat will damage your coaxial cable, melting the dielectric material and shorting it. Do not use too much solder, just the right amount to fill the braid. You will see the solder being absorbed by the braid, If the solder is not absorbed, you need more heat or the coaxial cable is not clean enough. If you use too much solder, it will be impossible to install the Pl-259 connector to the cable.

step 5

The next step is to cut the dielectric material above the braided area you have just soldered. Use a sharp knife and be careful not to cut the center conductor wires. The Belden 9913 has an aluminum foil shield on top of the dielectric material, make sure that there are no wires from the braid or foil touching the center conductor. Trim them as necessary.

step 6

Now, insert the Pl-259 ring with the threaded part facing out, do not apply any solder to the center conductor wires. The Belden 9913 (solid center conductor) and the Belden 9913F (stranded center conductor) have a large center conductor diameter, if you apply solder to the center conductor it won't fit inside the center pin of the PL-259 connector. On other coaxial types, like RG-8/U or RG-213 it is a good idea to apply a little solder to the tip of the center conductor wires. Since the diameter of the center conductor on these coaxials is smaller than the Belden 9913, it is not a problem when trying to install the connector on them.

step 7

In this step, you install the PL-259 connector body to the end of your coax cable. Pliers are needed to help install  the connector to the coax cable. Stop, when you see the braid thru the four holes on the connector barrel and the center conductor is visible at the tip of the center conductor pin.

step 8

Now,  it is time to solder your connector. Before you start soldering, it is a good idea to file the four holes on the connector barrel with a thin round file. This will expose the metal below the nickel plating on the connector barrel and help the soldering process. If you are using silver plated connectors, this step is optional. Smaller wattage soldering irons will require more time to heat up the barrel of the connector to an acceptable temperature for the solder to flow. If high wattage soldering irons or soldering guns are used, care must be taken not to bring the temperature of the barrel too high, or you will end up shorting the coaxial inside and ruining the connector. After you have soldered all four holes, solder the tip of the center pin. Please allow enough time for the connector to cool down between steps. Do not use water or any other substance to force cool the connector body to speed up the process.

step 9

The completed Pl-259 installation. Once the connector cools,  it's time to inspect all the soldering, you can file or scrape any excess solder on the connector tip. Slide the connector ring toward the Pl-259 body and screw it carefully, making sure there is no solder residue on the threads.


The last step is to verify the connector for any shorts. Using a VOM (volt ohm meter) or DMM (digital multimeter). Measure the resistance between the tip and the body of the connector. You shouldn't get any reading (infinite resistance) when performing this check. If there is a low resistance reading, your connector is shorted and a new one will need to be installed. If you have never installed a Pl-259 before, it is a good idea to practice on a small piece of coax, just the cable preparation and connector installation, not the soldering. Once the connector is soldered it is very hard to remove from the coax. Avoid using paste flux, to help with soldering and never use acid type solder.( the one used at plumbing) Rosin type solder contains the right amount of flux inside and as long as the coaxial is clean and not corroded it will flow easily and provide a good connection.

The tools needed for the Pl-259 installation are, soldering iron or soldering station ( I use a Weller 921ZX), a sharp knife or coaxial stripping tool,  small flush cutter or small scissors, a large cutter (to cut the coaxial), medium size pliers and a thin, round metal file. Materials needed for the installation are, PL-259's (I use the Amphenol 83-ISP-1050) 60/40 rosin core solder (Radio Shack 64-009 or equivalent) and the needed length of your choice of coaxial cable. Always keep the tip of your soldering iron clean and tinned. A small sponge soaked in water is recommended to clean the tip of your soldering iron periodically. On the 921ZX station I use maximum heat (850 F.), to solder the connector barrel holes and (700 F.) to solder the tip. If you need any help with your Pl-259 installation or have any question, please  e-mail me. I hope this tutorial helps tackle your PL-259 connector installations. Good luck!

Monday, June 25, 2012

Baofeng UV-3R MK II Dual Band Mini Hand Held

Front view of the Baofeng UV-3R MK II The UV-3R is a mini dual band hand held that covers VHF from 136 thru 174 mhz. and UHF from 400 thru  470 mhz, power output is around two watts in high power and less than one watt in low power. The radio is available in blue, black, red, yellow and camouflage colors. The price fluctuates between $40.00 and $50.00 including shipping from different vendors on the internet and E-Bay. Most of the vendors are located in China, there are a few dealers in the United States, but expect to pay a little more.

Back view of the UV-3R MK II with the battery cover removed. the radio uses a 3.7 volt, 1500 ma. lithium ion battery similar to a cell phone battery. It is the same size and shape as the Yaesu VX-3R, also a mini dual band radio.

A close view of the right side of the radio. The top rubber protector covers the speaker
microphone/programming jack. the bottom rubber protector covers the dc input/charger jack.

A close view of the left side of the radio.From top to bottom,ptt switch, f/a switch and l/r switch. The antenna connector on the top is an SMA type and the antenna supplied is a dual band antenna. The older model before the MK II comes with two different antennas,one for VHF and one for UHF. You have to switch antennas when changing bands or upgrade to a dual band antenna. I have used the Nagoya NA-701 with good results with this radio and the Yaesu VX-3R.

Close up view of the top portion of the radio. From left to right: antenna socket (SMA male)
LED for the flash light function and rotary control with lock . When pressed inside, the knob is locked, when pulled, it un-locks and lets you change frequencies, memories, menu items and adjust the volume. The knob works in conjunction with the front and left side switches and even lets you program the radio without the programming software.

Rear view of the UV-3R with the battery and cover removed. The notch on the top part of the cover is for the belt clip installation. The belt clip is installed to the metal top portion of the case with a Phillips screw. The battery terminals are on the top right side of the radio's battery cavity. The cover is secured in place with a small sliding lock on the bottom of the radio.

The Baofeng UV-3R includes an external charging dock for the battery. You can charge the battery inside the radio or in the cradle. While the battery charges outside, the radio can sit on the back. Charge an additional battery while operating the radio.

Battery charging cradle with the charger connected. On the latest versions of the Baofeng UV-3R MK II the supplied charger is a USB type 5 volt charger, the USB to Baofeng mini jack cable is included. You can charge your battery from a USB port on your computer or with a USB car charger. On older versions, like this one, the cable can not be removed from the charger.

The remaining accessories included with the Baofeng UV-3R: The belt clip,ptt speaker microphone ( in ear type) and a landyard. I have noticed that on some versions the length and color of the  lanyard  varies. On this particular version the lanyard is blue and has power printed  in English and Chinese. (white letters) A problem has been reported in some versions when using the speaker microphone supplied or aftermarket hand held speaker microphones. The radio will stay in transmit after the ptt switch is pressed in VHF mode. A disc capacitor must be installed inside the ptt switch enclosure on the speaker mike. This modification is available on the internet and Youtube..

This is the programming software screen as it looks when you open the UV-3R programmer. The file was downloaded from Before entering any information, first you need to connect your USB or serial programming cable to your computer and configure the port (this is done under settings). In my case, I am using a USB cable with the Baofeng type plug on the radio end (a four contact 3.5mm plug). I ordered the cable from Mega 409 Shop on E-Bay. Once you are all set, start by entering the receive frequency, transmit frequency, receive tone, transmit tone (can be ctcss or DCS) wide/ narrow and tx power. Select the scan type on the left, the step (5,10,15 kHz etc) assign your priority channel, the squelch level, vox level, time out timer, and channel name if any. Remember the Baofeng UV-3R has 99 memory channels, start by channel number one and keep entering the remaining memory information in the order you prefer. I started with the simplex frequencies, then moved to the VHF repeaters and last, the UHF repeaters. Since there are not many active repeaters in Puerto Rico, I was able to enter all my favorite frequencies in just 49 channels. I noticed that the UV-3R program has some "bugs". When I started entering the frequencies on memory number 8 (146.83 rx and 146.23 tx) the frequency changed to 146.22999 automatically.The radio display showed this change. I had to program the radio with this frequency change and then manually, enter the correct frequency using the radio's programming instructions. This happened on several of  the forty nine memories I programmed.

This is the programming software screen as it looks with all the information entered for the forty nine memories. Once you have entered all frequencies ,tones and settings,verify there are no errors,open the
program tab and click, write to radio. You will see a small screen popping out showing a progress bar.
When it is done, click the file tab and "save" your programming information. If you wish to make changes later you can open the file,make the changes and reprogram the radio. You can also use the software to "read" what is programmed into it.To do this, open the program tab and click, read from radio. The software is free to download and works well, except for the "bugs" I have described. If you have any questions about the Baofeng UV-3R programming, manually or via software, feel free to contact me. Any other contributions to this information about the Baofeng UV-3R are welcome.

For the price of this radio, I can not complain. It is a very capable radio,frequency wise. The only drawbacks are the two watt power output (sometimes two watts is not enough for distant repeaters) and the somewhat clumsy response of the front and side panel switches when operating or programming the radio via its own buttons. Leaving the confirmation beep on all the time helps with this issue. Make button presses slowly and listen for the confirmation beep. When programming from the radio, make a list of your frequencies and program simplex first, minus offsets second and leave the plus offsets for the end. Remember the Baofeng does not set your offsets automatically. The nice aspects of the radio are, the good ,loud audio (500 milliwatts) and the very little background hiss on receive. Other handhelds,even on strong signals have a very irritating hiss at the background. Radios like for example, the Kenwood TH-F6A, Icom IC-Q7 and IC-T90A are terrible reproducing the hiss. Another thing to keep in mind is that the UV-3R is a DSP radio, it is like a direct conversion receiver,going straight from the band pass filters into the DSP chip.Many people on the internet  describe it as a zero IF radio. The other radios on the market are conventional two or three conversion designs and I think that this difference is what makes the Baofeng so quiet and pleasant to listen . The radio also covers the FM radio band and has a very good recovered audio on this mode too.Like many Chinese transceivers, the built in flash light, torch, LED is included. RFI immunity is one of the weak points on the Baofeng, it is practically useless on the VHF band in close proximity to computer monitors and my D-Link DI-624 wireless router Wi-Fi signal interferes badly when operating on VHF. On the UHF band it works a lot better,with very little interference from monitors and Wi-Fi signals.The best radios I have tested regarding RFI immunity are the Alinco DJ-C5 and the Yaesu VX-3R. Both radios lack a powerful audio output but the resistance to interference is amazing. I hope this information helps deciding about the Baofeng UV-3R purchase. There is a new model that will eventually replace the UV-3R MK II ,it is called the UV-3R Plus. The same radio in a different case, styled to match the new UV-5R. I tested the UV-5R and found it to be a better radio in terms of power output and other features, but the audio is on the bright side and with higher hiss on the background than the UV-3R. Receive sensitivity (MDS) is comparable to the other radios on the market. The antenna plays a very important role, I have used the Nagoya NA-701 with good results on the UV-3R and the Yaesu VX-3R. For the price it is an amazing radio,even taking into the account the negative areas mentioned.

Monday, June 18, 2012

Welcome to my new blog. I decided to create it, to expose my projects,operating activities and ideas ,with other amateur radio operators through out the world. I was first licensed in 1979, WP4AOH is my original Novice call sign. I have over 35 years of experience in the electronic field, most of the time as a two way radio and audio technician. Since 1983 I started my own business, R.F. Electronics, in San Juan P.R. dedicated to sales,  repair and installation of two way radio, audio/video equipment and more recent, alarm and cctv equipment.I have built hundreds of kits, since the era of  Heathkit's, to the modern Elecraft's. An aavid experimenter with special interest in antenna construction, telegraph keys, vintage equipment, restorations and kit building.This blog will cover several areas of the amateur radio hobby, including QRP, antennas and antenna construction, soldering techniques,transmission lines, modifications,home brewing,morse code ,telegraph keys, high speed telegraphy ,transceivers, receivers, tuners, and power supplies, just to name a few. If you want  to help with any particular project or want to contribute to the blog, feel free to contact me with your ideas or sugestions to improve it. You can follow me on Twitter and Facebook. Please contact me via the blog or to the following e-mails, or I will always answer all e-mails as soon as possible. Thank you for taking time to read my blog.  WP4AOH

MFJ Cub 9320 Qrp Transceiver Repair and Modification

MFJ Cub Model 9320 single conversion QRP cw transceiver. Purchased used on E-Bay a few months ago. The volume and tuning potentiometers were replaced. Previous owner or MFJ ( I am not sure if it is a 9320 or a 9320K) installed the pots on the incorrect board locations. The MFJ Cub's volume and tuning potentiometers must be soldered to the mounting pads (holes) closest to the front board edge. There is a second row of pads about 1/4 " further inside the board. If the pots are installed to the inside pads, the potentiometers won't fit flush against the front panel, thus creating excessive force and stress the potentiometers when tightened. The incorrect installation damaged both controls, the volume could not be adjusted and the tuning was unstable. After the controls were repositioned and replaced, the transceiver now works like a champ.

Transceiver's rear panel view-  Notice the antenna connector, an RCA type jack. Notice toroidal inductor L-11 through the knock out for the BNC jack installation. The MFJ Cub is in its original configuration, except for the addition of the BNC jack. Covers about 60 kHz of the cw portion on 20 meters Power output is about 2 watts with 12 vdc supplied, and a little more when connected to a 13.8 volt power supply.

Internal view of the 20 meter Cub with top cover removed. The  transceiver is supplied fully assembled or in kit form. The surface mount components are pre installed on the kit version. More information on the MFJ website

BNC connector modification, the BNC is wired to the RCA jack in parallel. The ring (ground) terminal of the BNC is bent 90 degrees, cut and soldered to the RCA's jack top ground portion. The center conductor is connected to positive (central) part of the RCA jack with a piece of solid hook up wire. The wire at the same time will prevent an UHF to RCA type adapter not (center pin cut ) to touch or damage toroidal inductor L-11 if inserted.

Comparison of two different type of UHF to RCA adapters. Needed to connect the antenna to the transceiver in its original configuration. On both connectors the tip needs to be cut or filed to about half its length, otherwise when the adapter is inserted it will touch or interfere with toroidal inductor L-11

An introduction to the Sideswiper

My favorite video showing the correct manipulation of the sideswiper , also known as cootie key.
Thanks to Carlo Consoli, IK0YGJ for the excellent demostration.