Hi Phil The polyphase network manual http://qrp-labs.com/images/polyphase/polyphase2.pdf has a graph of measured audio response vs frequency and it is flat to about 2.5kHz. The primary intention of

The roll-off I am seeing occurs well below the 24 kHz limit of a 48 ksps audio interface. The horizontal axis in the screenshot is labeled with frequency. I can't really think of any advantage to the

So I am assuming, that it is not so much that the "Dorji DRA818V" unit is not capable of being a receiver because of the LightAPRS-W that it is incorporated in is not set up to be able to

Mustafa Tan wrote: Joe, It does contain this But the RX side is not enabled, unnecessary for a pico baloon. It may be possible to use the RX but my guess is that it would not be an easy task. 73

Am I correct in saying that since the output of this circuit is rectified ac, the peak voltage can be measured with a DC multimeter? If so, the peak reading squared divided by 100 does

After I wrote this, I got to thinking (something I should have done first). Hans is correct. My apologies to those who think more methodically. Paul - AI4EE 😢

Are we getting different pages/ this is the link I posted, http://qrp-labs.com/lightaprs-w.html and in it is this, The

Hi, Unfortunately LightAPRS is TX only. TA2MUN

Joe, But that is not the link in your original post...

Hello alan, In the description... VHF Radio Module: Dorji DRA818V and you go to the link the first thing it says is, VHF Band

Very handy Andrew. I will print out chart. Thank God April Fools is over!

Hi, I am finding it hard to believe all the trouble people are have with some basic Maths (well sums really), using a scope is a good method, however, you must be aware of the bandwidth of you scope,

Hi Allison, many thanks for your reply, yes I spotted the bias feed just after placing the query on the group. I have checked the voltage feeding into IC4 on pins 7 and 9 and they

VHF Radio Module: Dorji DRA818V is a TRX, but as far as I understand not active as an RX. We are running here, near Munich, a HAB project with some youngsters. As we are quite close to the Alps we

Progress! And QCX still working. All good.

Update: After a full charge the battery is reading 13.1v open load. I tried the MFJ-cub and again, same as before. Full scale deflection on SWR FWD into dummy load, RTN showing 1.5:1 which seems

Weekday contests (disguised as activity periods / QSO parties) are now coming true - https://rsgb.org/main/blog/news/rsgb-notices/2020/04/01/rsgb-contest-committees-launch-hope-qso-party/ I guess

Sorry, but DC voltmeters still don't measure AC/RF signals. They measure DC, which is why they are called DC voltmeters.

Joe Looks like TX only? 73 Alan G4ZFQ

Hi Paul There are errors in this... you are mixing peak voltage, and peak-to-peak voltage. No... Vp / sqrt (2). The difference is Vpp (Vpeak-peak) and Vp (Vpeak). Vpp = 2 x Vp. No... again, this is