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wrote: Ok, there must be something... Ok, Should have either made no difference or better. Worse is totally unespected! crystal filter. When you say 440 did you really mean 470? Thats what was

Hi On my first BITX (a BITX20) I used PN2222s and also found the gain to be quite low. After substituting a handfull of 2N3904s my gain became much better. Another early BITX builder found that his

I dont see the problem at all. If you inject a 3mv signal, and you get a 20mv signal, the circuit is working just fine. here is how, you need to check the power gain, not the voltage gain. Now, a

Hi! Just keep in mind 2N2222 metal and PN2222 plastic have different lead configration. Its C B E L to R for metal where as it is E B C L to R for plastic when viewed from front. Leads

Allison, Here are my AC and DC measurements for the Q3 amplifier circuit. I had used a scope to measure rather than my voltmeter, so measurements are eyeballed. With R set to 12V from an external

Hi, I just won on Ebay a large lot of 10.7 Mhz Crystals. If anyone wants to use this intermediate frequency I can provide a matched set of 4 plus a 5th for BFO. This IF would be useful primarly in

1) Checked. These are 10 ohm resistors. I've made 2 stages so far and had double checked all values of resistors going in. 2) I had been using 0.1 microfarad (value code 104) for all of

Edited. inline comments. wrote: Another thought.. One possible is that the 10 ohm emitter resistor (in series with capacitor) is not 10 ohms! It is sometimes easy to get 100ohm and 10 ohm by error.

wrote: Ok, just curious. Either those are very poor quality versions of MPS2222 (defective lot?) or something is very wrong. Could it be measurement error? That works well you unless you use really

All, Here is the new archive for BITX20 Engineering diagrams. I have reposted a new archive, EGR\BITX_REV_C, containing all the corrections for Revision B diagrams, plus GIF translations done by

Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the BITX20 group. File : /EGR/BITX_rev_C.zip Uploaded by : eternalesquire

Allison, No, I intend this to be used as 20M. I just use a colorburst crystal oscillator for signal tracing, and I used a scope to compare the incoming and outgoing signals to measure gain. I wired

Hi, Orange, pink and purple/violet are common to 10.7 IF coils. Allison KB1GMX

For calculate resonant frecuency in used TOKO or FI cans can be used a practical old know formulae: F(MHz)= sqrt(25330/(L(uH) * C(pF))) or L(uH)=25330/(F*F(MHz) * C(pF)) or C(pF)=25330/(F*F(MHz)

wrote: They are in 10,7MHz: orange 1? IF 10,7 (This is the can to be used in BITX) (100pF capacitor in parallel) green 2? IF 10,7(uncommun) (100pF capacitor in parallel) pink

Does anyone know the colour code for TOKO 10.7 Mhz printed citcuit transformers? Which are the IF , oscillator and dicriminator colours? Jim VE3DDY

Inline and edited. wrote: This is very low gain. The expected should be far higher in the order of of around 16DB. I would expect to see around 100mv for 3mv in. I'm curious why 3.579nmhz? IS

Hello, Two weeks I finished my experiment with the 9MHz crystal filter design and reported the results of it in several files in the File-box Ladder Crystal Filter Design. I dropped a message in

All, Thanks for the info re crystals, it will come in handy when I am ready. Next question: I have now finished building the first bidirectional amplifier after the preselector. I injected a 3 mV

All, Thanks for the info re crystals, it will come in handy when I am ready. Next question: I have now finished building the first bidirectional amplifier after the preselector. I injected a 3 mV