Yep, this is an off-the-wall question..... Paging through an old QST, it dawned on me that when schematics are drawn, usually the earliest stages are drawn on the left side of the diagram. The speech input circuits for a voice transmitter; the antenna coupling and RF preamp (if any) for a...

HI, I'm building the ADC-40 made by KD1JV. I would like to know what kind of 10.7 FI is used as filter because there are several type of FI with different characteristics spotted by different color. Could someone tell me the color I need ? Thanks a lot.

You maybe knowing your microwave's inner workings. It uses a microwave valve which consists of LC chambers of 2.4 GHz. And they are excited with a dc hv of must be 50 Hz. Now we have two possibilities, the output is in trains or constant rf output. Who of the hams here can messure that...

Hi folks. Any Toronto all-grain brewers want peated malt? I'm not brewing these days, but I can whip up some peated malt for those that could use some in a test brew. I used some at my professional brewery some time back, but since it was shipped from the UK and moved around somewhat, it didn't...

Does anyone have the schematic of the Pasokon SSTV interface board please? Mine (interface) has developed a fault and I want to fix it. Thanks. Howard.

This has got to be one of the most original bits of home brew art I've ever seen! http://waterfuelcell.org/phpBB2/viewtopic.php?t=1034&postdays=0&postorder=asc&&start=0 Has anybody out there ever tried something like this? I wish I could figure out how to scale this down to wind smaller...

I'm using the wein bridge to generate audio tones that are fed to the transmitter for digital radio communication (basically a homebrew ASK radio modem). I'd be open to using that, but I'm not aware of any radio modems that output square waves. This oscillator also has 2 digital pots attached: 1...

Anyone know where I can get a CA-5484 (that's a manufacture part no. not Realistic I think it says matsumi on the top of the can)osc coil from a Realistic DX100 receiver it's 1.6-4.5 MHZ it looks like the old 6 transistor radio can transformer.

Hi All, Modern engineering text indicates that for the same frequency, a large fully illuminated dish will provide more gain than it’s smaller equivalent. Why is this ? Consider the following scenario: ======

Hi I have the Delhi selfsupporting tower, it is 48ft tall I believe, an old ham tower. It has the top piece plate but I need the plate that is about 5 ft down. The previous owner of the tower made some home made ones for each 1/3 length of the tower but now I need the replacement for the one plate...

Hi all, I saw a site where a fellow designed a unit to measure impedance at 2.4 ghz, for use on wifi antennas. I don't recall if it was return loss or impedance. It gave detailed instructions on how to build and he also had ready built units for sale. I think it was a ham that designed the unit....

In a box of traded parts I found a cylindrical object labeled "Clevite Ceramic Filter TL10D16A" that may be some sort of IF filter according to very dusty old memory files. I would appreciate it if anyone knows of this brand and can give me an approximate center frequency and, perhaps,...

I have the following General Radio equipment for sale. All of it is in very good condition and working: The following items I would like to sell as a set: 1 874-LB 55 cm Slotted Line 1 874-LV Micrometer for the slotted line 2 874-LTL Trombone lines 1 874-GA ...

Hi I have a 50 ft tower just ready to throw up something to operate. Cost is the problem but I have a lot of parts to build. I want to put up a dipole (I have a manual all band tuner) and my question is should feed it with ladder line or feed it with coax and then run each leg about 68 ft...

HI, Often I can see coils where some turns are shorted in order to modify there value. I wonder whether these shorted turns would not be seen as a short cicuit and could decrease the quality of that coil. How can I have an idea of the lost of quality without complex equipment ? I plan to build...

Anybody have a source of plans for a solid state 222 amplifier project? Looking to use discrete transistors (versus a 222 brick module) for a little more power out. Looking for something that will take something like 5W in and give 75-100W out. Design should use 13V power supply. Scott N0EDV

I drive a 1988 dodge dakota which has an electronic control module to control timing and fuel delivery.I've installed a 10/12m ranger 2970 radio in it.I've also modified the radio somewhat by installing a modulation/speech processor/compressor.My modulation is presently at 95%.When I key the mic....

Hi I am building a (240volt in) 13.8 volt (out) PSU along the lines of this plan.. http://www.warc.org.uk/proj_psu.php it is very similar to the old Marchwood practical wireless unit from the early 1980's using 2n3055 transistors. My question. The spec says the transformer must have a secondary...

If this is the incorrect group, then please send me to the proper one. I want to demonstrate the sound of cw with my own message. I have a sound card. How can I create a wav file that can be saved on a flash drive? OR By using DM780 or MultiPSK, can I create a cw message that can be saved on a...

Hi gang, Anyone know of an sites of folks doing homebrew HD radio demods? There are several sites out there for doing shortwave DRM (Digital Radio Mondale), but I'm wondering if any efforts have been made to build similar hardware/software for the HD radio broadcasting that takes place on the...