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Folks I am working from the (c)2004 circuit on Ashar's web page and have very low output from PA. I am using cheap general purpose transistors (ME4003) and changed pre-driver for 2N2222. Better but

Dear forum, I have read somewhere from the posting messages that the output of pre driver should be about 300 mWatts, but I read from the article it should be about 300 mVolts. Which is right

Hi Chris, Rather than guess at Gautams question it is easy to ask. Saves giving multiple conflicting answers. I may add my favorite "cheap" Varactor [tuning] diode is 1n4007 rectifier. It also

Hi! Arv is quite right. Here we also took a similar route. First was the need for a cheap common PSU so we selected a portable BW TV transformer sec abt 20V AC unloaded around 1.25amp. Unreg DC goes

Gautam I am assuming that you are using the same size VFO inductor and capacitors as specified by Farhan. If you are using the original design with the 36V zener diode as a VFO fine tuning

gang capacitor my VFO shows 4.000 to 4.180 MHz(when trimmer shifted to 4.000MHz) and after tuning Trimmer(shifted to 4.150MHz) it shows 4.180 to 4.410Mhz. entire range i.e. 4.000 to 4.400MHz. Varies

Hi, I think the tuning range is found to be to small. Likely because the tuning capacitor does not have enough capacitance. (the LC combination defines the frquency and if the L is fixed, only the C

Hello, First the transistor used. The 2n222a or 2n3904 are excellent for this type VFO. I have tried to understand what problem you are having. I suspect the range of tuning 0-230khz is either

hi, in my bitx20 vfo frequency is 4.000 to 4.230MHz or trimming the trimmer i found 4.200 to 4.430 (i.e 0 to 0.230 MHz tuning range). aftyer several changing in coil and various types of capacitor(2j

Hi! Go ahead with 540. Let me know someone coming this side 510 is available at Lucknow. 73 Rahul VU3WJM kumar gautam <fromgautam@...> wrote: HI, HERE IN MARKET IRF510 IS NOT

Hello Hans, I do hope you got my initial response. The blocking may be enroute, it's not anything I can control. Do try to reply to the arrl.net address rather than direct. High power (greater

Hello, That IRF540 will be very difficult to drive with increasing frequency. The input will be very reactive and will require a more complex network to get the needed RF power (and voltage)

Hi Kumar, The datasheets give the following parameters: IRF510: RDS = 0.54 Ohms; ID(continous) = 5.6 A; maxPower = 43W; Input capacitance = 180 pF IRF540: RDS = 0.077 Ohms; ID(continous) = 28A; max

Apologies list, for the bandwidth - I am having some trouble emailing Allison on private email. Seems I am blocked somewhere :-( 73 Hans G0UPL http://www.HansSummers.com

HI, HERE IN MARKET IRF510 IS NOT AVAILABLE, ONLY IRF540 IS AVAILABLE. ANY ONE HELP ME THAT IRF540 IS EQUIVALENT OF IRF510 OR I CAN SUBSTITUTE THIS FET. WITH 73'S DE KUMAR

Good old crush and plaster ah, rather cut and paste. ;) Oh well, you found it and dont forget there is information in part 2. linear...something might Since you ask. I've done it on paper and it

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 : /Spectrogram517-4filter.exe Uploaded by : vu3wjm

Hi Chris and Julius, In the experiments with 9MHz filter the crystals turned out to be about 9.015MHz. With the BFO exactly on 9.005 MHz I get both sides of the filter and I can determine the

The Gram zip file have about 250Kb of size and I can?t upload now I will try later... 73 PY2OHH

Hello friends I am building another BITX40, my other with two bands work great but there are many external boxes to plug togheter... If you are looking articles for mesurenents of filtres by sound