The Island homebrew project

[N8YX]

We have some pretty talented designers, builders and tinkerers among the membership ranks and it would be nice to see what the group as a whole could come up with in regards to usable radio equipment.

So...let's plug the irons and scopes in then get busy. But with one twist:

Each Island member designs ONE section of the project, which will be in modular format. It shall also use readily obtainable parts - as an example, filters from popular OEMs or easily obtainable surplus...or variants which the homebrewer can easily and cheaply duplicate .

A complete HF transceiver or separate receiver/transmitter might make for an interesting start.

Two requirements to start the ball rolling: Should be synthesized -or- tuned by a very stable PTO/VFO arrangement and use frequency mixing.

You folks can design either (or both) frequency generation schemes. If the forum members built one of each type, they could be swapped in and out of the parent circuit at will. Same with the other sub-assemblies.

To that end, standardize a construction and connector scheme which will allow for "plug and play" with well-defined I/O and power requirements for each board. Will you folks follow the lead of Drake (a la TR7, R7) and Yaesu (FT-90x) and Collins (KWM-380) with their plug-in, motherboard-style cards or will you emulate Kenwood's 820 line designs, which made extensive usage of header-style interconnects to the various modules...and therefore required a complex main harness? A mix of both - emulating construction techniques used in Signal's CX-11 and Milspec 1030 series? Something of our own creation?

Opening the floor for discussion of the design particulars...

[KA9MOT]

Awesome idea.....wish I had some skills....

[KG4CGC]

School's starting early on The Island. I'll watch and take notes but once my mind starts ... like breaking free old rusty wheels.

[NQ6U]

Awesome idea.....wish I had some skills....

I'll make the front panel...

[PA5COR]

Once in the far distant past made a 9 MHz i.F. transceiver for 2 meter, though that I.F could be used for other frequencies just as well.

PLL, i have some experiments done, simple around the MC 4044 i.c. and Huff and Puff stabiliser.

I think we have better people here as me ;)

[WØTKX]

What about an autotuner project?
Or maybe the Island Audio DSP?

Signal One construction technique? :lol:

Hell, let's build with surplus wire wrap! :shifty:

(edited because the advanced editor dorks with the white spaces in Safari. :rant: )

[N8YX]

What about an autotuner project?

A novel idea. Perhaps it could be integrated with the project transceiver in some fashion?


Or maybe the Island Audio DSP?

See above.


Signal One construction technique? :lol:Hell, let's build with surplus wire wrap! :shifty:

By this, I meant containerized (shielded) sub-assemblies which make use of SMA or similar miniature connectors for signal ingress/egress, and shielded/filtered DC supply/control lines. Hilberling, Cubic, Mackay and Collins (among many others) adopted this construction method. It allows easy substitution of "defect" modules and keeps unwanted intrastage coupling to a minimum.


I'll make the front panel...

Panels. Not just one. Everyone who participates in this effort should have at its completion a working copy of the project. In turn, the others will build and test 'their' modules for 'your' rig.


Once in the far distant past made a 9 MHz i.F. transceiver for 2 meter, though that I.F could be used for other frequencies just as well.

9MHz is also a pretty common crystal frequency, so an array of filters shouldn't be hard to fabricate from discretes. We could even make each array tunable via varicaps, allowing the operator to set each passband to his or her preferences.


Awesome idea.....wish I had some skills....

Acquire them along the way. Can you solder? Follow "kit" directions? The average ham should be able to duplicate our efforts, not just an electronics lab tech with 30 years experience in said lab. That doesn't mean we can't make the overall design robust and fully featured - it implies that esoteric or tricky fabrication procedures are to be minimized or avoided altogether.

[WØTKX]

I can accidentally cut myself and bleed on the circuit board. I have skillz. :mrgreen:

Helped somebody dig around inside of a CX-7 years ago. It was interesting, as it was designed to be worked on. This gent was a major Elmer of mine. He swore a lot working on stuff, very lulzy. SK, I now hold his call sign.

[N8YX]

Helped somebody dig around inside of a CX-7 years ago. It was interesting, as it was designed to be worked on.
On the other hand...a lot of Kenwood gear which comes to mind wasn't, at least by the "amateur". If serviceability is important, the equipment should be designed to accommodate such from inception. In an effort such as we're contemplating, ease of module exchange is going to rank very high on the list of requirements.

Let's throw out a couple of idears here and start the ball rolling:

Transceiver/receiver/trans-receiver should employ the following frequency scheme:

At least two and preferably all HF bands.
Up-convert the first IF (~45MHz) and use a passive 1st mixer with at least +17dbM LO injection; > 23dbM preferred. There are lots of off-the-shelf 45MHz 'roofing' filters to choose from.
Use a 9MHz 2nd IF.
Use a third IF or either 455KHz or 500KHz. (The latter frequency is popular in surplus ComBloc communications equipment and a goodly selection of 500KHz filters can be obtained from eBay.)

[NQ6U]

Not wanting to poop on anyone's parade here but there is (are?) a metric shit-ton of homebrew HF transceivers out there. I'd like to suggest building a all-mode 2m transceiver instead. Try to find one of those these days; if you're lucky enough to find one for sale, it's going to cost you big bucks.

[N8YX]

I'd like to suggest building a all-mode 2m transceiver instead.
If a building-block approach is adopted, any frequency range could be covered simply by adding on the appropriate RF modules. Control/interfacing would be standardized among them.

As fas as VHF/UHF operation is concerned, 6/2/220/432-440/902 would be nice. Maybe 1.2GHz. Full duplex operation to work the birds or allow for cross-band, remote-control operation.

[WØTKX]

Actually, a VHF/UHF all mode would be pretty cool. 220 abilities would be quite nice.

[N8YX]

Let's think about that a bit. Maybe define as a requirement that a "band module" (or a 'range module') input and output a 9MHz IF signal, a TX/RX command line, preamp control line, roofing filter select line(s), accept a VFO input signal of a predetermined amplitude and provide information to the parent (controller) board telling the parent what it is.

Given sufficient chassis space, one could place any number of modules into the unit. This architecture would easily lend itself to remoting...

[WØTKX]

The frequency bands we get in the VHF/UHF are a bit wide and don't fall into place as "neatly" as the HF bands. A couple of different IF schemes?

"6n2 and 220 Too". Make it look like Drake and Ten Tec had a baby. ;)

Maybe keep 70 Mhz in mind for other ITU regions? :dunno:

Have a few 1.2G repeaters here now, as well as some 900's. Weekly SSB net on 144, 220, 440, and 1.2.

[Happy_Hamer]

Found this on our site,

http://youkits.com/

[N8YX]

Found this on our site,

http://youkits.com/
One wonders how many of those building blocks could be incorporated into other designs. :chin:


The frequency bands we get in the VHF/UHF are a bit wide and don't fall into place as "neatly" as the HF bands. A couple of different IF schemes?

Yaesu managed one (10.85MHz) with their FT-726R series, and its band modules covered everything from HF through 440MHz, sans 70 and 220. For 902 and 1.2GHz, an on-module down-converter might be employed.


Maybe keep 70 Mhz in mind for other ITU regions?

Heck, keep it in mind for US. 6-to-4M transatlantic, multiple-hop E is beginning to attract the interest of a lot of hams on the eastern seaboard. A fully functional transceiving module -or- a receive-only version of same could be built and used by folks on both sides of the pond...

[KG4CGC]

I was looking for the guy from this thread: http://forums.hamisland.net/showthread.php?10110-Low-Tech-Homebrew-Style

Looks like he has taken down his videos. Why? I have no idea. Probably pissed off Nate.
This guy explained everything the radio, homebuilt, was doing step by step. It looked a little ratty but that was a simple matter of tidying up a bit.

So, I still wanted to share something. I found this. Unless the guy is also a machinist, I believe it could be a kit but he says it is build from parts. http://www.youtube.com/watch?v=uz4adNRvyfU&feature=related

[mw0uzo]

Sounds interesting :D
I could contribute a PIC controller? Got loads of code from my beacon project that could be used. LCD control, menu system, PWM control etc. An auto atu from fixed caps and inductors switched by relay/other method shouldn't be a problem.

[W1GUH]

First things first.....

Gotta pick out the knobs to use.

[WØTKX]

I still think an audio DSP like the BHI unit would be really cool.

[mw0uzo]

I still think an audio DSP like the BHI unit would be really cool.

Do you know much about digital signal processing? I can write digital filters, don't know much about noise reduction though.

[mw0uzo]

This looks very interesting http://sox.sourceforge.net/
T (http://sox.sourceforge.net/)he project could be hardwareless (apart from your pc of course)

Look at the features list

Tone/filter effects

allpass: RBJ all-pass biquad IIR filter
bandpass: RBJ band-pass biquad IIR filter
bandreject: RBJ band-reject biquad IIR filter
band: SPKit resonator band-pass IIR filter
bass: Tone control: RBJ shelving biquad IIR filter
biquad: 2nd-order IIR filter using externally provided coefficients
equalizer: RBJ peaking equalisation biquad IIR filter
fir: FFT convolution FIR filter using externally provided coefficients
firfit+: FFT convolution FIR filter using given freq. response (W.I.P.)
highpass: High-pass filter: Single pole or RBJ biquad IIR
lowpass: Low-pass filter: single pole or RBJ biquad IIR
sinc: Sinc-windowed low/high-pass/band-pass/reject FIR
treble: Tone control: RBJ shelving biquad IIR filter


Specialised filters/mixers

deemph: ISO 908 CD de-emphasis (shelving) IIR filter
earwax: Process CD audio to best effect for headphone use
noisered: Filter out noise from the audio
oops: Out Of Phase Stereo (or `Karaoke') effect
riaa: RIAA vinyl playback equalisation

Analysis `effects'

noiseprof: Produce a DFT profile of the audio (use with noisered)
spectrogram: graph signal level vs. frequency & time (needs `libpng')
stat: Enumerate audio peak & RMS levels, approx. freq., etc.
stats: Multichannel aware `stat'


Thats a very handy list of functions!

[mw0uzo]

Audacity uses SoX to do its noise reduction processing with noiseprof and noiserd. A test to see if the noise reduction in Audacity is any good would be interesting.

[WØTKX]

Audacity NR is pretty good. Never tried it on a radio input, just recording from tape and LP.

I don't know much about DSP, which is why a project would be cool. I do run a Flex 3000 and built a SoftRock 40 SDR that was pretty interesting. The Flex blows it away of course. Audio DSP for voice is what I'm after, and that's of course the trickiest. My MFJ-784 works great for narrower modes.

[NQ6U]

Okay, I've been working on this project for days now and I've come up with an excellent receiver design. I think it will work nicely for the Island homebrew project.

http://sci-toys.com/scitoys/scitoys/radio/simple_radio_schematic_2.gif

[ab1ga]

No way that solid state junk is going to withstand a halfway decent EMP.

[K7SGJ]

Okay, I've been working on this project for days now and I've come up with an excellent receiver design. I think it will work nicely for the Island homebrew project.

http://sci-toys.com/scitoys/scitoys/radio/simple_radio_schematic_2.gif


Too many parts.