开云体育

An NPN of cause not. The 8 volts will hold the base of the PNP high causing it not to conduct and not pulling the coil to ground. If you use an NPN the transistor will be in conduction when in receive

*** Not an NPN? That's really weird. Generally, if you want to short a positive voltage to ground, you use an NPN. Also, you'd want to have a resistor in series with the base to set the base current.

Correct Curt, Unfortunately many hams forget that ham radio is secondary on a lot of bands and must yield to other services and cause no interference John

For those who need to key an amp for the G1M transceiver this little circuit works very well. The TIP30 is a PNP transistor but you could use any PNP transistor as long it can carry the current of the

If you look up cricketsat you will see references to using a single chip 433 MHz chip to make an expendable payload for balloon flights and the like. Our club had launched a few. Oh this band is used

Vic I know you said you checked the board but i am familiar with board problems at my employment. Im not saying it is the board, but id probe around in ohms and vdc and make sure traces/vias are still

What about 315Mhz and 433Mhz in the U.S.? I've tested a few car remotes with my TinySA and have found both frequencies in use. Max KG4PID

The GaN transistors are now used in small phone adapters. They are really inexpensive. Someone needs to figure them out.

There are ISM allocations in the HF and low VHF spectrum, albeit narrow ones. The 13.56 MHz frequency (bandwidth of allocation 14 KHz) used by Metcal soldering irons is the one that is probably best

Power supply and capacitors. wrote:

Tom I see reference to ISM bands, to aid our non US folk this is spectrum allocated primarily for non communication apps. These are UHF or higher. And many short range unlicensed apps use this same

This link specifically mentions 1.8 to 50MHZ. https://www.nxp.com/products/radio-frequency/rf-power/rf-defrosting/1-8-50-mhz-rf-defrosting:RF-DEFROSTING-1#/ Tom, wb6b

Hi, Looks like NXP is trying to promote the idea of a computer controlled HF power module for defrosting food in the kitchen. Just like mass production of microwave ovens has lowered the cost of

Jerry If you want to see an example 10 watt rig examine the k2 schematic. Its a bit involved. There are also some decent examples of rigs using relays. Well enjoy each rig for what 8t does. Oh wear

*** How about PIN diodes? Yeah, they're expensive, but apparently 1N4007's work fine. See https://www.qrp-labs.com/images/50wpa/QCX_PA2q.pdf starting at page 53. Also see

I tried changing the value of C81 by paralleling some other caps with no real change, but just looking at 20m. Looking at the history of folks measuring power across the bands, my readings in the

Hi Farhan As Jerry pointed out, this is the thread about the low-pass filter kit for the amplifier. It comes assembled, but consistently with a lot of errors, like the wrong capacitor on the 80m

I measured mine with a nanoVNA, not a tinySA. This was a Chinese switchable LPF off Ebay. Assembled, but apparently not tested. - Jerry

As I had mentioned earlier, the TinySA is not very suited for measurements like this because it doesn't have sufficient shielding. Shielding makes it expensive and heavy. The third harmonic must be

Jerry, It would be a very extensive effort. 1. Given similar power levels, a 2N7000 in place of the antenna relay should work. A few more transistors can isolate the rx signal path. This is the easier