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Kees, after having some trouble I got the sketch from? Duwayne? (KV4qb blogspot) to play, even with a 0.96?? and 1.3?? I2C display. See

The frequency response of the second IF filters of the Ubitx vary from unit to unit depending also where the BFO is set. My unit for example is about 2khz wide filtering out frequencies below 700hz.

Hmm... It may be improper level of LO injection. On the transmit side, the mixer has _very_ strong input termination and LO termination. It will be interesting to study this. Mixers can provide

Would be interesting to pop the lids off the various TDA2822 parts, examine the die under a microscope. I'm betting the WX looks significantly different than an ST.

You think the WX might be a repackaged TA2822D meant for the SOIC8? I doubt it. I think the WX is a cheap copy that simply doesn't meet the 15v absolute max spec We had reports that there are clones

You missed my point Jerry. I am not suggesting 2822D. Please see the spec sheet I attached. It is a lower power version of tda2822. I think that die is being repackaged as TDA2822 in 8 pin DIP. It

Thanks, everyone, for the comments.? It is great information. Looks like I need to wait a little longer. 73 Mike KK7ER

I believe that should work fine. Given the significant power and the relatively low voltages, the impedance at the drain is quite low.? A little bit of extra capacitive coupling is not too

The four transmit filters we have are all low pass filters. The spur Allison found is below the operating frequency, so those filters don't touch it. When operating at 28mhz, the spur is at 45mhz -

Hello fellow constructors I have been thinking about using a common heat sink for the RF power transistors, insulated with mica washers of course and insulated mounting hardware. Would there be inter

Very neat Peter!

Spend a weekend with a Nano, the OLED, and a breadboard and the example code and you'll have it working in less than a week even if you don't know programming. If I had JackAl tucked away in bed, I'd

Beautiful! Jack, W8TEE

I am not sure if 28 mhz is a problem. I am travelling so I will go back and check. I switched to 4 filters to be fcc compliant from 3.5 mhz to 28 mhz. - f

On 21Mhz rather than a band pass/high/low filter what about 23mhz trap(s) also called notch filter. Even high Q should be wide enough to cover whole 23.8 to 23.55Mhz.?? Similar for? 24Mhz needs to

The various BITX transceivers present an interesting and educational opportunity to determine the accuracy of our test equipment, test procedures, and interpretation of all the above.

I'd recommend you check to see if the transverter takes care of the spur for you. At 28mhz, the spur is at 45-28=17mhz going in, and something around 30 dB down from your 28mhz signal. The transverter

Table two of the arrl.org filter reference shows that the 21 mhz bandpass filter? has 15db of attenuation at 28mhz, that's 7mhz away. We need something like 20 dB of attenuation at 2mhz away. As

If all I need is to use the ubitx as a 28Mhz IF for a 2m transverter then all I need is a 28mhz high-pass, correct? I would think that it would be easy enough to build a high-pass in order to kill the

I followed Joe's (VE1BWV) lead and checked out Robotshop.ca and found the 2.8" display for about $25 CAN. This is a pretty reasonable deal and it showed up in a couple of days. We will see how long it