hi bob i have just found some time to build my doppler unit and i have a couple of questions to ask you or the group. 1 when you take the audio from the...
Chris... You will have to provide your own speaker, you can just tie it in parallel with the audio input of the PicoDopp. Conversely you can jumper the ...
--ok bob thanks for the help i havent looked at this doppler for a while so i have just had a look at the website to get me upto date. i have just tested the...
hi am just going to build the antenna platform this weekend . this will be for 145 mhz , my 1/4 wave whips are 19 and a 1/4 inches and the side spacing between...
Sorry for the delay, that sounds fine Chris... it really isn't critical at all... spacing must be less than 1/3 wavelength and most folks use 1/4 wavelength. ...
Here is just some food for thought. With extensive testing, the "ideal" spacing I (the driver) and Fred K8FV (mastermind with a scope and patience) found was...
Just to let you know another factor is the antennas. A dipole on a ground plane has an impedance of about 26 to 30 Ohms. To get 50 ohms you either slant the...
My PicoDopp unit was a MAJOR help yesterday in winning our club's foxhunt. I took along a conventional yagi, HT, and compass to use if necessary because this...
hi bob i have been testing my doppler all week. but i have been getting some strange readings. with certain stations it will not give me a reading , i have...
Hello Chris... Looking at the photos you posted on the forum of your antenna platform, it appears the antennas are not arranged in a square... that's important...
Just a FYI to you antenna builders: It is difficult to solder SS with ordinary acid core solder (even worse with rosin). I am redoing my cartop antenna setup....
... with ... antenna ... I ... have that. ... had planned. ... Hi jerry you have to silver solder stainless steel with flux and solder works great I do it...
Boy, I wouldn't even attempt that... stainless steel is formulated specifically and deliberately so that nothing can get a grip on it, ( chemically ) that's...
thanks for the fast reply bob. sorry about the pic of the antenna platform, but it is 2ft by 2ft square and the spacing is 18 inches each side it is just the...
Ok Chris thanks for the additional information... As for selecting one antenna at a time, you can "stall" the crystal oscillator on the PicoDopp MAIN board by...
If you construct your antenna with a disconnect between the antenna switcher and main board, it’s easy to manually bias each diode with a jumper wire. That...
Thanks very much Tim, it's always edifying to hear such things... good luck with the magistrates... it's approaching haloween, possibly you can have him burned...
Chris In my humble opinion the problems you are having are due to receiver bandwidth. I have been working on a project and got similar inconsistent results. I...
thanks for the info pat,but i think i might of found the fault. i just done some testing and the coax ground and the antenna ground were common, i found that...
No I don't think that would explain your problem. In fact, I doubt it would have much effect at all. For Pat : Chris has already tried 3 different recievers....
ok bob i have tried 3 good quality scanners 1 icom r3 2 aor 2002 3 aor 2003 and they all give me different results with different signals and i have to tune...
I can suggest some reasons but they would only be guesses. Things you can try are : (1) confirm the scanners are set to FM mode, since some scanners allow the...
Group I looked up the specs on the 3 receivers used and unless they are set to the wideband mode they will exhibit the sane problem I came across with the IC...
-ok pat thanks for the info and taking the time to work it out. i am going to redo the switcher into a better box and i will try it next week.........chris.......
From Bob S. : Happy holidays to all... I've posted a photo of a new DF design ( on this forum ) that is approaching completion... I presently call it...
I've sold MicroHunts before that were used for link transmitters with audio modulation inputs... also one fellow did APRS with one, using an external TNC......
