开云体育

Chris, & others... Please take a closer look at the BITX IF string without any crystal filter. There would be no control of the passband and thus no way to tune a specific frequency, other than as a

Dear forum, The problem of my crystal measurements has solved :-). Thank you for your advice :-). I try change the transistors from BC547B to 2N3904. (maybe I got 2nd grade quality of BC547B) Then

Sorry folks, I don't know what I did wrong but the post was only intended to be sent once to three groups, not three times to this one. abject apologies for wasted space. atb Mike W

Hi,why the intention to add one x-tal as a filter if you want to generate DSB? Just remove the current IF filter from the design and you have already DSB! By doing this, you can also investigate

Hello from EB1CPC / EC1ACV , in Spain. I try to build the BITX20. I have the PCB but I have many doubts about the location of many components in the PCB. Can anybody help me?. Anybody send me the

HI Folks, I've just found this url in a newsgroup that may be of interest to someone out there :-) http://www.qsl.net/k1jhj Using AVR's in both projects, with free development software, free

Hello, I have just uploaded a file with the results of my measurements of the IF filters passband. The set-up was a DDS-VFO as a signal source and a HF millivoltmeter as a detector.

MILAREPA@............. It would appear from your chart that the higher frequency crystals may not be oscillating, or that your frequency counter may not be capable of counting above 10 MHz. Lets

Dear forum, ==About Crystal Measurements== At the time I mail to BITX about this subject, 'actually' I was using a 3.579545 MHz crystal, that available at my junkbox and drifting is in this

Following a suggestion from Dave M1DGS I have enabled the group message archives for reading by non-members. This means that visitors to the group are now able to view all of our messages in the

Mike Some time ago (actually, many years ago) I remember reading somewhere that you can make up your own "binocular cores" by stacking two rows of conventional toroid cores. That's about all I

Hi Sadly it appears that a spammer has joined our group and sent a spam email which I received here at 1809 UTC. I have deleted the offending message from the messages archive, but those of you

Hi Hans' comments (see below) are very appropriate to the measurement of Crystal frequencies. I too found that if you solder the crystals in place, it may be necessary to wait several minutes for

Your circuit and method look Ok to me... how bad is the drift, and what happens if you wait longer than 5 minutes? The drift could also be in your frequency counter (or PC if you are using that as a

Hi Arv, Thanks a lot for the very detailed reply to my query and for offering to advise me on any problems I might face with building the trx. Knowing that I can bank on the group's knowledge and

Paolo In the US, plastic knitting needles are available for an attractive price. These range from 1/8 inch to 1/2 inch diameter. The smaller ones are easily ground to a screwdriver point using

Bharat The discrete component AF Amplifier file is in the FILES and PHOTOS sections of the BITX20 forum on Yahoo.com You should be able to view and copy them from there. If you have problems please

I have found a 'source' of minature binocular balun cores in old UHF TV tuners and computer UHF modulators. there are usually, it appears, one or two per tuner. Not tried them yet though. atb Mike

Dear forum, I try to measure my 12 MHz IF-crystals with method here, for purpose selection within 30 to 50 KHz ( is this value right ? ). But the problem is: Frequency reading is still moving /

Hi Paolo, I cut/filed a piece of PCB to the right size and sanded of the copper. The slight advantage over a toothbrush is that the material is less soft, so it can handle screws that are tight or