You can get them on ebay;

http://www.ebay.com/itm/500mA-Bench-Top-Meter-NEW-/380603397258?pt=LH_DefaultDomain_0&hash=item589dbaf48a

http://www.ebay.com/itm/Vintage-Milli-Ammeter-1ma-EDM-Lab-Bench-Meter-/181110883867?pt=LH_DefaultDomain_0&hash=item2a2b0cc61b

etc.

Hammond make some, eg;

http://www.hammondmfg.com/dwg16.htm

and cheaper ones are available, eg;

http://www.jaycar.com.au/productView.asp?ID=HB6094&form=CAT2&SUBCATID=986#1

You can also cut a plastic or diecast box at an angle, eg;

http://i49.tinypic.com/24e6q2d.jpg

It's not easy to see in this photo but the rear is about an inch higher than the bottom front; I did this years ago with just a hacksaw and a file.

A nice filter; you can find out how it works here;

www.axtal.com/data/publ/mcf.pdf

(The page numbers are muddled-up which is confusing).

The greater proportion of filters described in amateur literature and built by amateurs are of the ladder variety; I have assumed that it is that kind of filter that we are discussing.

I previously referred to " ... the difficulty of making simple ladder filters with a high bandwidth/centre-frequency ratio ...".

Zverev (chapter 8, p.422 in my edition) covers the matter mathematically and observes that "... the obtainable bandwidth of the filter, as is easy to recognise, is dependent on (the ratio of Cp to Cs)..."; since Lm is constant, Cp determines the parallel resonance frequency and Cs determines the series resonance frequency, so that Cp/Cs is equivalent to Fp/Fs.

To clarify; when designing simple ladder filters for SSB-type bandwidths, choose a high IF, perhaps 9 or 10 MHz or even higher.

I accept that ",,, quite difficult ..." is too strong; I regretted using this term when I re-read my post.

A warning about the difficulty of making simple ladder filters with a high bandwidth/centre-frequency ratio would be a better way of putting the point.

The sentence that followed my quoted comment reads;

"The difference (between series-resonance and parallel resonance) increases with crystal frequency which is one reason for using 9 or 10MHz crystals instead of lower-frequency ones".

The principle remains; the parallel-resonance causes a lop-sided response; this asymmetry increases as the filter bandwidth increases.

W7ZOI described the effect in QEX (Jun 1995) and, abbreviated, in EMRFD (3.20 & 21); W7AAZ (unpublished paper) advises us to "... be aware that filters that are a large percentage of the crystal frequency may not be possible in simple ladder filters ...".

In pers.com to me W7AAZ has also commented that "... In technical terms, you cannot make a filter wider than the difference between series resonance of the crystal and parallel resonance with the "holder" capacitance. In fact you cannot approach that width very closely. Thus a 4.434 MHz xtal with a spacing of 5 KHz makes it very difficult. SSB width ladder filters are easy to make at 9 MHz where the two resonances are separated by 15 KHz".

I think that you should consider actually measuring the response of the filters you have built.

Your Flex Radio looks like a useful signal source with either 5 watts or 1mW available.

I did say earlier that your 'scope would make a good detector but, considering the power/voltage levels involved, I don't think that's correct; it would not have the required sensitivity.

An AD8307 meter as described in EMRFD and elsewhere is ideal; I used mine a great deal for this kind of measurement, entering the DUT output at various frequencies into Excel and producing response graphs of filters, amplifiers and the like before I graduated to other test instruments.

Just the basic AD8307 with a DVM on the output is trivial to construct for low frequencies but a kit such as KA7EXM sells would be worth building.

If you measure your filters you will have information that will help you decide what, if anything, is wrong with them and how you can improve them.

It's possible to design very good crystal filters but it takes some effort; the crystal parameters are important.

Many simple projects use a few crystals of unknown specification; sometimes it works, sometimes it doesn't, sometimes the builder is unsure.

Crystal parameters can be measured with simple equipment; a signal source and a detector.  You have those in your radio and 'scope.  Suitable attenuators will embed the crystal-under-test in a 50-ohm or 12.5-ohm environment (see the K8ZOA paper referenced below).

The G3UUR method doesn't even require that, just a simple oscillator, but it does require a frequency counter.

These methods are somewhat tedious if you are sorting large batches of crystals; better equipment speeds the process but is not essential.  It's usually necessary to measure a lot (20 - 50) of crystals to sort them into reasonably-matched sets for filters but, if you want good filters, that's what you have to do.

Jack Smith K8ZOA has written the best paper on crystal measurement that I know; go to http://www.cliftonlaboratories.com/Documents.htm and find the Crystal Motional Parameters paper.

A fixture similar to Jack's is excellent for the series-resonance method; the G3UUR oscillator is simple to build if you want to try that.

Filters can be designed once you have the parameters; the free program from the AADE site is a good one but there are several others available for downloading.

It's perhaps counter-intuitive but good narrow filters (CW bandwidths) aren't difficult to make; the wider SSB filters are quite difficult.  The essential reason is the small frequency difference between the series resonance and the parallel resonance of a crystal; you can only make a filter with somewhat less width than that difference.

The difference increases with crystal frequency which is one reason for using 9 or 10MHz crystals instead of lower-frequency ones.

I've looked in my computer files and found a few articles that are available on the 'net;

www.arrl.org/files/file/QEX.../QEX_Nov-Dec_09_Feature.pdf

http://www.giangrandi.ch/electronics/crystalfilters/xtalfilters.shtml

http://www.w0qe.com/Projects/crystal_bandpass_filters.html

Patient searching using various search terms will find a good deal more.

I've found working with crystals to be fun; I've worked my way through all the measurement methods described by K8ZOA, from simple series-resonance to the final graduation to VNAs.

Capacitors have a property called Equivalent Series Resistance (ESR); that is a "real" resistance that dissipates power in the form of heat.

ESR is made-up of lead resistance and dielectric losses.

Your 150-watt amplifier will drive roughly 2 amps into a 50-ohm system.

ESR of ceramics depends on the type of dielectric and is usually in the range of 0.1 ohms to 0.01 ohms for common types.

0.1 ohms at 2 amps will generate 0.4 watts whilst 0.10 ohms will generate 0.04 watts to be dissipated as heat.

Since you are unlikely to be able to measure ESR, next best thing is to try it and check the temperature of the capacitor while it's delivering power to an antenna or load; if it gets hot you should replace it with either a better one or two or three or more of appropriate value in parallel which will dissipate heat better.

I think 6 - 10 of each of the following would be a good start;

FT23, 37 & 50 in 43 and 61 materials.

T37, 50 & 68 in 2, 6 and 10 materials.

BN202 & 2402 in 43 and 61 materials.

FB43-101 beads

BN43 & 61 in 2402 and 202 shapes.

That's 21 different types I think.

I have picked these from my very large stock list as being likely to be most used but it does depend a little on what you want to do.  You will find more as you go along; when you need one, order six until you end-up with 43 different kinds as my Excel list shows me. 

Essentially the T-cores will make good tuned-circuit inductors and the FT-cores will make good transformers/baluns as will the BN-cores.

The little FB beads are useful to slip over a component lead to dampen oscillations.

Don't forget DIZ for toroids etc; even in VK I order from him as the prices and the swift service can't be matched.

Always mark them as soon as you receive them; I use paint pens from a hardware shop with my own colour-coding.  Yellow, for example, is 43-material whilst blue is 61-material; I also have a red pen and a green pen; combinations of two colours can be used to provide myriad type-markings.

I think the chart on p9 of the manual could be used to work-out the inductance of coils E, F & G; this might be a useful short-cut.

For example, 100pF in // with coil E resonates at 26 dial divisions; the frequency will be the frequency corresponding to coil D at 26 divisions.

The inductance of coil E can then be calculated.

A similar procedure would find the values of coils F & G.

Once you have the inductance of one or more coils, the value of the variable capacitor can be calculated from the dial markings; the inductance of the remaining coils can then be calculated.

I think this should work.

The pin plugs may be microphone - connector standard like this;

http://www.altronics.com.au/index.asp?area=item&id=P0949

(They have a "proper" designation number but I can't remember it at present    ).

I have converted female connectors of the kind shown in the link to male connectors with brass pins inserted into the female receptacles and held with epoxy; this was for a cable for a Boonton power meter which uses a two-pin connector of this kind but with reverse gender.

I think that "quick in & out" is the key to all good soldering, SMD or otherwise; you should make the joint in the time it takes to count "one".

I use 350C on my station for leaded-device or SMD soldering.

I also think that using a tiny tip isn't the best way; use a small tip but one that has a bit of mass and holds some heat.  The needle-pointed tips aren't good at transferring heat to the joint; use a chisel-tip or a wedge-tip.

The tip is like a reservoir; it has to hold some heat for transfer to the joint.  The heating element is only for heating the tip; if you are relying on the element to heat the joint you will have a poor joint.

A pointed tip has little interface area between the tip and the joint so heat transfers slowly; a tip with a small flat surface transfers heat much more quickly.

Solder paste is good; Cash Olsen sells it at cost in small quantities.

But Kester 44 is great; I use it a lot.

Just remember; fast-in, fast-out!

A Google search for "power supply kit" gets quite a few hits.  These look OK;

http://www.circuitspecialists.com/powsupkit

but there are several others.

These are just regulator boards; they require a transformer.  A plug-pack is actually quite useful; it removes heat, bulk and weight from the device it powers.

I built a "plug-pack" for one of my projects for just those reasons;

http://i46.tinypic.com/23iapzn.jpg

http://i45.tinypic.com/2qxuc9i.jpg

Don't dismiss the humble plug-pack.

An AC plug-pack would drive a regulator PCB like the ones in the link above but note my later comments about voltage.

You should read about/Google for information on LEDs, particularly driving multiple LEDs.

LEDs are not usually driven in parallel; small differences between them mean that different currents flow in each one.

They can be paralleled (I have done it) but it's not good practice and can blow the LEDs that "hog" the current.

Series connection is usual; that means that a supply voltage greater than the sum of the LED drops is required.  Say six in series, each with a 2v drop; that's 12v @ 20mA.

(LED voltage drop depends on the colour and varies over a range; I used 2v for simplicity.  20mA is the usual current for ordinary LEDs).

To drive those six series LEDs through a current-limiting resistor, about 15v would be required; that gives a resistor value of 150 ohms.

To use 20 to 30 LEDs as you propose you could use a series/parallel circuit; series connection of, say 5 LEDs minimises the current-hogging problem so four parallel strings of five LEDs each string would work for 20 LEDs.

Each parallel string should have its own resistor; in the above example, a 15v supply with a 250 ohm resistor in each series string would work.

(Hope my maths is correct; I just did it in my head).

Another thing to consider; you may not need a regulated supply, just a single diode or a bridge with a transformer/plug-pack and a capacitor.

Millions of LED garden/path lights and similar lights work this way; it's much cheaper than a regulated supply and just as effective for non-precision applications.

Rick Campbell KK7B has written several articles on direct-conversion receivers; the articles appear in QST and other places I think and he wrote a detailed section of Experimental Methods In Radio Frequency design about DC receivers.

Incidentally, EMRFD is the experimenter's Bible; no home-brewer should be without a copy.

Here is an article by KK7B;

www.arrl.org/files/file/Technology/tis/info/pdf/9208019.pdf

It explains the design in step-by-step form.

I think that kits are available for some of the designs; Kanga, for instance, has the micro R2;

http://www.kangaus.com/receivers.htm

and FAR circuits has just the PCB;

http://www.farcircuits.net/

Building one module at a time and testing it is a very good technique; here are modules of a DC receiver based on the EMRFD section;

http://i47.tinypic.com/2v2ch9f.jpg

You will require some test equipment; a signal generator and an AD8307 microwattmeter will be a start and construction of the wattmeter (kits are available from KA7EXM and others) will be good practice.

Thanks for that; I would like to know the outcome.

Looks as if the OP has moved-on; pity, I would like to know the answer.

I note that the Alinco spec is for harmonics better than -50dBc (HF except for 10m) and -60dBc (6m);

http://i47.tinypic.com/ezo6c.jpg

It's entirely possible that the "Bird" test is the one that gives the correct result, esp. if the reported results were measured at 50 MHz.

Thanks for the clarification.

I'm inclined to think that the analyser is overloading in the "attenuator" setup.

If you have 100w (+50dBm) TX output, the 20dB attenuator gives +30dBm at the analyser input.

This is very close to the +34dBm input maximum.

I'm not familiar with the 8285 and I had some difficulty in interpreting the data sheet but I imagine that the SA section is little different to any other SA; the difference would be that the 8285 has a lot more fixed attenuation at the mixer input.

For comparison, my SA has a specified maximum input of +20dBm but it begins to go non-linear at about 0dBm; I have tested this.  I have disposed of my other older HP SAs so I can't test them but memory says that they behaved similarly.

I have always tried to keep SA inputs around -20dBm or so, ie 20dB below distortion level and 40dB below maximum input power rating; applying this reasoning to your attenuator setup, there would be -6dBm into the SA requiring 56dB of attenuation.

As far as the "Bird" setup is concerned, the data sheet says that maximum power transfer/minimum attenuation (that's how I interpret the table I posted) is 57dB at 10 MHz.

That would result in a SA input power of -7dBm from 100w/50dBm; this is a good deal less than the +30dBm input from the "attenuator" setup and is close to ideal for a good measurement with the 8285 if my reasoning is correct.

The argument against my reasoning is as you said; the "attenuator" results seem believable whilst the "Bird" results seem too good to be true.

My work is mainly in micro-power; I've occasionally checked an amateur transmitter over the years but I don't remember one with (if I interpret your "Bird" results correctly) a second harmonic better than -60dBc.

I know nothing of the Alinco; perhaps it's capable of that as KE3WD remarked.

Try adding a lot more attenuation to make 50dB or so and see what happens to the second harmonic level.

You might like to try another method of "tapping" the TX output; a coupler;

http://i47.tinypic.com/315k37p.jpg

http://i45.tinypic.com/2vhw5ro.jpg

http://i50.tinypic.com/vdea7o.png

I built that one not long ago to use on the bench where BNCs are useful; I built this one;

http://i47.tinypic.com/3480g06.jpg

years ago for use with UHF connectors.