using “bargain” coax connectors

die on incorrectly threaded so239

 

I bought a package of 10 SO-239 chassis connectors on eBay at a great price.  The connectors looked good, teflon insulation, gold plated pins.  However it was not possible to thread a PL-259 male connector on more than 2 or 3 turns.

I then understood why the price was so low.  I decided that the solution was to re-thread the connectors.  I looked for a die at local tool stores but no luck –  I was told that 5/8-24 was a thread used in electrical connectors but not commonly used by machinists.  Checking on Amazon it became clear that the proper die was available at reasonable cost as a “gunsmiths” die.

 

As soon as it arrived I tried it.  I did not have a holder for this size die so I used a “Quick-clamp” with rubber pads.  I used lots of cutting oil and took my time cutting the threads.  The result was a bare brass thread which easily took the Amphenol PL-259 connector.

I don’t know if the manufacturer in China used a 16 mm die in place of 5/8″ or if they failed to take the thickness of the nickle plating into account when cutting threads.  Whatever the reason now I have the tool to make it right!

 

The photos tell the story.  73 and keep on building.  Earl VA6TJ

 

 

die on correct conn after rethreading rethreaded it worksu

VE6MV granted DX award

DXCC Honor roll

Congratulations to Denny, VE6MV for achieving Honor Roll status.

 

Okotoks sunset

Had a great weekend with our son and daughter in law in Okotoks. Had a fantastic sunset one night. Here are a few shots. Check the Gallery for more or click the newest image on the home page to link to the Gallery.

Bob

VE6BLD

 

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Remote antenna tuner

Remote tuners are offered by MFJ, LDG and others.  Here is my brief review of the LDG RT-100 tuner.

I purchased the tuner new, at what I considered was a competitive price.  As you can see from the photo I am using it to tune a horizontal loop antenna close to the feed-point.  The tuner is matching a short section of low loss open wire line and not a long section of coax.  The tuner requires 12V DC at low current so I powered it from a gel cell battery and a small solar trickle charger panel (CND$14).  This remote solar power arrangement has been in operation for several months now without issue.labeled installation show all

The tuner finds a match from 80 – 10 meters on the random length loop (~130m of #10 multi-strand insulated wire, 10m high).

I have found a few issues with tuning; i.e. failing to find a good match on a band or frequency.  As per the instruction manual a tune can be “forced” by changing bands, re-tuning and then returning to the frequency you want to operate on.

The second issue noted is a de-tune with changing weather / moisture conditions.  For example rain or heavy dew on the antenna may cause the antenna to re-tune.  This does not often happen but it is inconvenient there is a re-tune cycle in the middle of a QSO.

tuner interiordownload

I experimented with different baluns and found that a 4:1 air core balun worked best for me.  This balun is very easy and inexpensive to make using parts from the hardware store.   The antenna is maintained at DC ground through the balun and tuner. (Yes, the ground wire should have been green…major fail !)

 

weatherproofed balun

 

Using the remote tuner I was able to operate on SSB effectively on multiple bands with a single wire antenna using only 100 W.  The loop antenna was found to be very quiet as a receive antenna.  On 20m a signal barely audible on a dipole was perfectly Q5 on the loop antenna.

So if your opportunities for erecting antennas are restricted my experience shows that a multi band wire antenna with a remote tuner and one feedline can be an effective way to operate HF.

Needed a place for my antenna

Needed a place for my antenna in the shop for the local UHF repeater,
works good.
Egon VE6EGN/SA3EGNuhf_antenna

Maxdroid

 

Maxdroid

Modification to add a digital display and continuous frequency selection to VHF/UHF Maxtrac transceivers.

By

Avinoam Albo, 4X1HF Avinoam.albo@gmail.com

December 2014


opening pic

Conversion of a Maxtrac to a transceiver with display and frequency selection

In this article I will explain how to convert the venerable Maxtrac to a rig more user friendly to radio amateurs.  The modification requires  the addition of only a few inexpensive and easily available components.  When the modification is completed you will have a rig with digital display and frequency selection enabling continuous  coverage over the whole range of frequencies  where the VCO locks.  An external programmer is no longer needed.

Disclaimer:  Carrying out the modification described requires basic electronics skills.  Any modifications are the sole responsibility of the technician. This modification will likely void type certification for commercial radio service.   This article does not make any specific claims or recommendations.

Specifications of the transceiver after this modification

  • Digital display
  • Continuous frequency selection
  • Selection of transmitter output power (2 levels or more)parts required
  • Selection using VFO or memories
  • Selection of VFO frequency steps (5K, 10K, etc.)
  • Receive PL (on/off)
  • Scanning and saving frequencies to memory (future)

Required Components 

  • Maxtrac VHF or UHF
  • Arduino Nano 328 controller
  • Rotary encoder
  • LCD 08 X 02 (8 characters x 2 lines)
  • 3K, 4.7K, 8.2K, 10K resistors
  • Fine gauge insulated hookup wire such as wire wrap wire

Programming the transceiver More >

Horizontal Quad Antenna

Horizontal Quad Antenna

By:  Eli Kovo, 4X4LH (originally published in the IARC newsletter 08/2015 “HaGal” and used with permission of the author.  Translated by:  Earl, VA6TJ)

I recently came across an article in an issue of “73 Magazine” from 1978 raving about an antenna called “The German Quad” which [at that time] was used by about half the hams in Germany.   Below I summarize the main points of the article.

The first thing about this antenna is that it works without a tuner on 6 bands, from 10m to 80m and also on 2m.  I could not find confirmation that it works on 6m however I am confident that it will also transmit on that band.  Compared to a symmetrical dipole, the horizontal quad has the advantage that it can be fed anywhere, even at a point close to the shack as in illustration 1.

horizontal loop ill 1

More >

45th Anniversary a Success



The 45th Anniversary Red Deer Picnic and Hamfest was a huge success. There were 112 people registered.  On Saturday morning Radio World and other flea market vendors enjoyed selling new and used radios and accessories under a beautiful and sunny sky. Greg and Karen and Karen’s parents began the process of roasting of the pig at 3:00 AM! Thanks for your generous donation of the pig and all your time!  Everyone enjoyed the roasted pork and the pot luck dinner Saturday evening.  Following the meal we watched the 45th anniversary video produced by Vance VA6VAN. Thank you Vance, for editing the pictures and videos sent from numerous hams. The weather was great Sunday morning for the pancake breakfast, egg toss and the  draw prizes.

There were many people who helped in various ways to make our 45th anniversary hamfest and picnic a resounding success. A special thank you to Phyllis and the ladies from the 160 gang from Camrose for organizing the fun craft again this year!  Thank you everyone!

Bob King VE6BLD

CAARC President

Click pictures to see larger files

Picnic pic from RAKsmall

 

Picnic SAR CQ1small

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Pixie II v5.1 40 m QRP xcvr Kit by Earl 4Z4TJ

 

 

 

 

 

 

Pixie II v5.1 40 m QRP xcvr KitCapture

 

 

This small kit is a version of the old Pixie II, two transistor, direct-conversion CW “transceiver”.  Many Pixie IIs were made using Manhattan or dead bug technique.  Now a Chinese PCB version is available    on line at such a low price that you will say:

how can I not build this and try it on the air”.

In this application note I will share some of my experiences and suggestions regarding the kit.  The first question that occurred to me was:  “Is such a simple circuit effective as a communications device?”  The answer is yes, but with severe limitations.  In any event it is a fun project well worth the money.Capture4

The circuit is simple and mostly self-explanatory.  It incorporates some of the later mods developed for the Pixie II.  Q1 is a Colpitts crystal oscillator  using a reverse biased silicon rectifier as a varicap to pull the crystal frequency the 700 -800 Hz required to give a signal a pleasant tone when in receive mode.  This function also gives a small range RIT to clarify signals when listening. The frequency offset is adjusted with W1, the 47K potentiometer.

In transmit Q2 functions as a simple PA with a pi LPF output. This stage buffers the oscillator and increases power to several hundred mW. I measured 250 mW with a 9V supply, 500mW with a 12V supply (see photos).  General purpose 2N2222 type transistors are frequently used in Pixie II circuits.  I looked up the transistors supplied with the kit and was pleasantly surprised to find the kit manufacturers have gone to the effort of selecting components specific for local oscillator and power amplifier functions.

In receive, Q2 functions as the product detector in a direct conversion receiver with Q1 as the LO and U1 amplifying the detected audio to provide earphone volume. LSB as well as CW signals may be received.Capture5

Start construction by inserting 6-32 x ¾” hardware in each of the corner holes.  Head of the screw goes on the bottom (solder) side of the PCB.  Finger tighten.    These screws act as legs that allow the PCB to rest flat when soldering components.  If you plan to mount the PCB in a case this is the time to mark the mounting holes.

Solder the potentiometer and the socket for U1.  If you also wish to use this pot as a RIT use wires and a 47 K potentiometer mounted on the “front panel”.  Next solder the resistors, capacitors (polarity) and diodes (polarity) and inductors in that order.  Solder the transistors.  Solder the 3 mm stereo sockets the BNC antenna socket and the power socket.  I measured all the disc capacitors in the kit and found that they are 20%.  The inductors are also 20%.  I added a ferrite bead on the lead of L1 to bring the inductance up to the nominal value.  L2 was within 10% so I used it.  I was not happy about using -20% value capacitors in the LPF so I purchased 1% ceramic capacitors at the local components shop for 15 cents each.  It took about two minutes to wind a new 1 mH L2 inductor (15 t) on a T30-2 powdered iron (red) toroid. With the L/C meter attached I spread the windings till the exact value was found.  Fix the windings in place with a drop of glue.Capture6

Solder the 7.023 MHz crystal (you may wish to look in your junk box for a crystal that will put you on a QRP calling frequency; 7.030 in EU and 7.040 in North America).

Measure resistance across the power input.  Connect the 50 ohm 1 W composition resistor supplied with the kit or other dummy load to the antenna socket.   With a mA meter in series apply 9 – 12 V.  Current should be approximately 15 mA.  If it is much higher than 15 disconnect power immediately and check your work.  (D1 provides reverse polarity protection so a 500 mA fuse might be in order.)   Insert a Morse key in J3.  Listen for the oscillator on your station transceiver or connect scope probes across the antenna dummy load 51 ohm 1 W resistor supplied with the kit. Capture7

 

 

 

 

If the oscillator and PA are working as expected insert U1, connect headphones and a 40m antenna.  A 9V – 12 V battery works.

Phone another ham in your city and get him to zero beat your signal and then transmit.  Adjust the 47K trim pot for a pleasant tone.  You are on the air!

In the evening I connected a 9V battery, Air Canada complementary earphones and my 40m delta loop antenna.    CW stations from EU could be heard and tuned with potentiometer W1.

Now, where did I put that straight key that I used 40 years ago?

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CW chirp issues were solved by: 1) Preventing a change in voltage across the varicap, D2, when keying by keeping potentiometer W1 in the middle of its range. 2) Addition of a 22 uF 25V SMT chip capacitor on the bottom of the PCB, across the terminals of the power input socket.  To solder one side of the capacitor I scraped away some of the solder mask on the PCB — the other end went tight against the +ve lug of the power socket. (Check for shorts before applying power.)

RF power output with a 12 V supply was found to be 500 mW, as shown at left.  In addition, the higher supply voltage yields a waveform appearing closer to a clean sine wave, (photos above) generating fewer harmonics.

Note:  LPF:  I checked for 2nd and 3rd harmonics and they are easy to find within the shack.  I believe that higher quality components in the LPF will reduce harmonic radiation.  However, another ham in the same city could not hear the second harmonic (this is my spectrum analyzer equivalent test).   So, even with sub-optimum suppression, the second harmonic will be at a level of approximately 0 dbm – not a level that will wreak QRM havoc on 20m and 15m CW (second and third harmonics).

On the air results.

Hams within a 200 Km radius could hear the QRP CW signal.  After correcting the chirp issue reports were good.  Surprisingly the direct conversion receiver also let me hear them easily, so 2 way QSOs are definitely possible.  Listening on 40m just after dark let me hear most of the 40m CW band – all at once.  Stations could be peaked by adjusting the 47K trim pot. Where a few individual CW signals could be identified I found them on my FT-450 – surprisingly they were not S9+ signals but pretty ordinary S7 signals, indicating that the direct conversion receiver is quite sensitive.  Good sensitivity combined with poor selectivity effectively restricts 2-way communications use to daylight hours.  In spite of the receive limitation, it is pretty amazing that two way communications are possible with such simple, low cost equipment.

 

Conclusion

Lots of fun for the money!

To download this original article click this link

Pixie II v5 for caarc

 

  • Calendar

    June 2017

    Sun Mon Tue Wed Thu Fri Sat
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    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    4
    • ARES Net on the CAARC repeater system
    5
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
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    10
    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    11
    • ARES Net on the CAARC repeater system
    12
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
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    • Red Deer Picnic
    17
    • Red Deer Picnic
    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    18
    • Red Deer Picnic
    • ARES Net on the CAARC repeater system
    19
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
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    • Koffee Klatch Join the local Hams for coffee at the A and W in the Village Mall across from Wall Mart on the North hill in Red Deer. .Listen to VE6QE 147.150 MHZ plus 600 for directions. See you there!
    25
    • ARES Net on the CAARC repeater system
    26
    • CAARC 2 Meter NET Please check in to the CAARC net on VE6QE 147.150+ repeater.,VE6VHF 146.91-, VE6PZ 145.210 -, VE6UK 145.25 -...
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