Homebrewing QRP

Pixie II - Packaging List Instructions

Crystal Sets To Sideband‘ – http://www.wa0itp.com/crystalsetsssb.html

…thank you…very nice!

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Motorola MaxTrac

The radio is out of Hay River, NWT…2M, commercial grade, programmable channels, 80$.  Other than a couple of minor scratches its in great shape and cleaned up well. DSC00004 Personally I really have no need for a 2M radio of any sort; I don’t care for voice tx at all.  But a member of our club bought a stockpile of these and emergency communication is a part of what hams do.  This winter I’ll connect it to the Motorola PS and put up a simple antenna so I can monitor local repeaters…   Links: http://www.eham.net/reviews/detail/1632 http://www.repeater-builder.com/motorola/maxtrac/maxtrac-index.html

Six Men, Three Trucks, And a Backhoe

Today is October 6, 2014. Today it snowed. And today we erected the base of what will be a 60′ repeater tower that will provide 2M ham coverage between Swan River and The Pas, Manitoba, and link this site to the 2M network to the south. We had a great day!

We met in Swan River at 8 a.m.. It took us an hour and a half to drive north on Hwy. 10 and then up along logging roads – a rise of 500 meters in 11 miles – into our site on a prominence in the Porcupine Mountain.  Marty, VE4MRT had done all of the background work to gain the required permits from the Natural Resources Dept. of the province. And he had additionally gathered all of the required ham-related gear, tools, and manpower needed.

We had 4, 10′ sections of the tower and an 8′ subterranean base complete with pads that VE4MRT had welded.  Along with it we hauled a small diesel backhoe…

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We also hauled up an equipment shack complete with security door…

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 Snow made the last part of our trip difficult on steeper sections of the gravel.  Upon unloading, the backhoe went to work digging an 8′ deep hole…

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 …while the rest of us assembled the tower…

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…Gibb, the backhoe operator. worked quickly and efficiently…impressive to see what he can do with a small tractor…

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…a pulley and cable was attached to a birch tree opposite the hole from the tower…

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…the tower base was set in place with the hoe’s bucket…

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…manpower positioned the tower correctly…

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…propped up slightly a chain was attached to two of the legs and the cable from the tree was hooked onto it…

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…with the base in the hole the cable was tightened with my diesel F350 and slowly raised…another chain was attached to the trailer of the grey pickup in the background to stop the base from sliding forward…I eased forward while the other pickup eased backward…

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…two guys were tied on either side of the tower to stop lateral movement…

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…and the tower was set perpendicularly in to place and levelled!  Back-filling began slowly…

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…a 45 gallon drum provided water for tamping…

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…and shields were screwed on…

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…the shack was skidded off of the trailer and slid into location and levelled…

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…the horizon in the distance is 40 miles…and you can see farther on a clear day…

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…the shack is already wired and ready for equipment installation…

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…four hydro poles in total were then set, including a trench under the access road…two poles on either side…wiring installed with conduit…

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…the other two poles were set which will feed electricity to the site from an already existing line that powers a tower/equipment belonging to Natural Resources…

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…then it was cleanup as snow flew…

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…and congratulations on a job well done!  What a great group of hard working guys with whom to spend the day!!!  We arrived at 10 a.m. and left the site at 4 p.m. with no scheduled breaks.  This was all just preliminary site prep work that we will return and complete in the spring…

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Left to right: Bob, Dave (VE4NEG), Gibb, Joe, Marty (VE4MRT) (Craig (VA4SR) photographer)

Motorola TPN1110B Power Supply Wiring And Components: Working Your Way Through A Schematics (Rear Panel)

Schematics are traditionally written from left to right.  In other words, the flow of electricity through the components on the schematics begins on the left side of the diagram and flows through the drawing, ending up with the output on the right side of the page.  I began with the front panel on the previous post because the components on the face of the power supply are roughly laid out in that same order.  However, turning attention to the rear panel the opposite will be true…a mental reversal of the schematics will be called for here…the components will be addressed from right to left.

This is the pic of the Motorola TPN1110B rear panel, and I am immediately impressed by the beauty and solid construction at first glance.

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Motorola TPN1110B VHF Power Supply Rear Panel

This time working from right to left the major components that are readily visible are:

(1)  An aluminum box.  This is directly opposite the transformer mounted on the front.  A 110V AC power cord complete with a grounded plug (grey/not in pic) enters this enclosure on its right side and provides power to the unit. A familiar 110V AC outlet  is located on the back of this enclosure. This outlet is live when the unit is plugged in and is unregulated.  There is a black cap on the top left of this box.  Screwed off it contains a 10A fuse (F1) inserted into the wiring after the 110V AC outlet and before AC enters the transformer windings.  The wiring inside this box can be accessed by removing four screws that fasten it to the panel.

There are two holes through the aluminum plate above this enclosure.

(2)  The hole to the top left allows two red wires to pass through.  These are from a resonant, high voltage winding and proceed left to another enclosure that is the back side of C1 (listed in post about front panel).  This enclosure is marked Danger High Voltage and may contain over 800V.  On the face of this box is mounted the 13.8V DC (regulated) power strip.  Two wires, red and black, proceed from this strip and are the power source for VHF radios.

This same hole also allows three blue wires to pass through.  The two solid blue wires are each attached to their own diodes (CR3, CR4) and grounded at the top of the rear face plate along with several other grounds.  The blue/yellow wire runs down to the rear of the C10 capacitor, which serves as further rectification for the 12.9V – 14.5V DC portion of the regulator board located on the far left of the rear panel.

(3)  The hole to the top right allows the passing of three yellow wires.  Two of these solid yellow wires each run to their own diodes (CR1, CR2) mounted both above and below the rear transformer enclosure respectively.  The yellow/green wire is the main supply tap from the transformer for 13.9V DC regulated electricity.  This striped wire runs to the back of the first two main rectifying capacitors (C2, C3).  A black wire then runs from C3 to the inductor (L1), located in the approximate centre of the rear plate.  Two black wires then emerge from L1 and proceed down to the rear of the two lowest capacitor cans (C4, C5).  All of these capacitors have a common grounding bus that runs back to the top right of the rear of the plate and are grounded in the same location as the blue wires previously mentioned.

The last heavy black wire emerging from L1 then proceeds upward and supplies the four remaining capacitors mounted along the top left of the panel (C6 – C9).  These are all grounded again with a common bus ultimately attached again at the top right of the panel.  However, another ground wire also goes to the 13.9V DC power strip (TB1) in the centre of the panel.  The other side of these capacitors is then put through two resistors located at the far top left of the rear panel (R1, R2)…a red wire then attaches to the + terminal of the power strip (TB1).

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Regulator Board

(4)  The regulator board on the far left actually consists of two regulated circuits side-by-side…virtual identical images of one another.  Each is powered off of the blue/yellow wire and are separately fused (F2, F3), respectively.  The former protects the circuitry for the 9.6V circuit, the later for the 13.6 V circuit.  Each is connected to its own transistor (Q2, Q6) mounted on the panel below and slightly tot he right.  Both of these final  voltages are present in the five wire plug (P2) that is the terminal for these circuits.

Motorola MYCOR TPN1110B power supplies provide 13.8V of well regulated DC current for powering VHF transceivers.  They provide other voltages and a plug for interface with Motorola repeaters and other gear.  They are robustly built and easy to understand and analyze.  Better yet, these are becoming readily available, and like my own, may well be had for free.  What more could I want?

Motorola TPN1110B Power Supply Wiring And Components: Working Your Way Through A Schematics (Front Panel)

After cleaning this power supply and mounting it in the rack I carefully separated all  wires and plugged it into a 110V AC outlet equipped with a breaker.  The transformer started humming and there was no arcing; when it comes to any power supply this is always a good thing!

Studying the schematics I saw that there are three power outlets on this power supply.  The first is a standard plug that is located on the back of the panel behind where the transformer is located.  Using a volt-ohm metre this tested 110V AC (a good sign…and I later ground some coffee beans using this outlet just because I could!).  Next I tested the 13.8V DC strip, which once again is located on the rear of the panel in its centre.  This, too was spot on at 13.8V DC (a better sign).  Not needing the 9V outlet I decided to leave testing that for later (the coupe-de-grais when/if it comes!).

This is the pic of the Motorola  TPN1110B front panel.

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Motorola TPN1110B Power Supply Front Panel

Working from left to right the major components that are readily visible are:

(1)  A substantial transformer (T1) is mounted in its own bracket.  According to the schematic (https://va4sr.files.wordpress.com/2013/10/tpn1110-power-supply-schematic.pdf), this is a ferrous core transformer.  Ferrous material is used in the core of some transformers in order to introduce a certain permeability that will introduce a certain inductance to the windings (or at least not be hostile to them).  The value of the inductance  chosen by the manufacturer depends on the intended operating frequency as well as the bandwidth to which this inductor will be subject.   This transformer is being used on a VHF radio (2M) frequency and is meant to step down 110V AC to a regulated13.8V DC and 9.6V DC output. On the schematics this transformer is listed a ‘ferro-resonant’.

(2)  A series of capacitors (8) all marked with green circles (C2 – C9).  Capacitors are commonly used to store energy in the electrostatic field between their plates or to block the flow of DC.  These capacitor cans are all rated at 17,500 micro-farads and are grounded.

(3)  An inductor (L1/L2) that has a painted black frame with coated brown paper wrapping inside the frame.  This is located in the approximate middle of the panel and extends both to the front and to the back of the aluminum plate (these are actually two inductors mounted back-to-back).  Inductors store energy as well as restrict the flow of AC.

(4)  A shorter capacitor cavity is located to the bottom left of the other capacitors and has no coloured tag.  Its rating is 5,000 micro-farads and serves to rectify the regulator board (fuse protected).

(5)  The oblong/oval metal casing at the left of the top row of capacitors and above the bottom cluster of capacitors contains its own capacitor connected to the windings of the main transformer.  According to the schematics, this box may hold a voltage of more than 800V and should be treated with extreme caution.  It is rated at 6 micro-farads.

(6)  Two other components, mounted on an angle and toward the bottom right of the panel are transistors that are a part of the regulator board(s) mounted on the back of the panel.  Transistors amplify signal energy.  According to the schematic these transistors are of NPN design, meaning that the emitter and collectors both have negative charges.

(7)  The final component visible on the front panel is located at the top right.  It is a resistor and is paired with one on the back panel.  These feed off of the final main rectifying capacitor and are R1 and R2 in the schematics.  These flow to ground and are rated at 30 ohms each.

Radio Rack

Once again, with companies in our area trashing their old radio hardware this rack was offered to me.  It is ideal for holding equipment next to my operating station.  I will clean it and repaint it over the next couple of days.  Its width between uprights is 18″; my widest gear is 15″.  It stands over 5’6″ tall; it’s vertical opening is 5′.  The total height of all my ham gear that would go on it is less than that, and some of it can be placed on shelving side-by-side.  Plus it will hold the 2M power supply and amplifier perfectly as these were built to fit it.  It was suggested to me to put it on wheels so that if I need to change the cables/wiring it could simply be rolled out to do these changes…brilliant idea!

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