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Barett,

most probably you reversed the collector and the emittor of the PTT bypass
NPN transistor by mistake. This gives exactly the behaviour as you
describe.

Please verify you installed the NPN transistor correctly.

73 Allard PE1NWL

I finished doing all the mods today in the instructions minus the capacitive and automatic keyer just the straight key. The problem is when I key the mic. it goes into transmit but will not stop when I unkey. I have to hurry up and turn off the power and turn it back on to get it till stop.
--
Barrett
K5SSO

Hi, I've just released Raduino_v1.27.1, download it from

This release includes a few bug corrections (thanks Bob, WB4SON and Willy, W1LY for testing):

- fixed a bug that the spurious carrier burst was not suppressed in CW-SPLIT mode
- In semiQSK mode, the initial CW element is now delayed by 65ms (to prevent the carrier burst), instead of canceled
- fixed a bug that the radio did not reliably switch from LSB to CWL in semiQSK mode
- fixed a bug that the display got messed up when the VFO is above 10 MHz

Happy BitX-ing!

73 Allard PE1NWL

On Thu, Nov 9, 2017 at 08:03 pm, W0PWE wrote:

So then I followed one of Jerry's (KE7ER) suggestions and modified my sketch to use his?si5351bx code. That was really easy to do and?si5351bx_setfreq()?took about 2ms to execute

I just measured it on my own Raduino, and found that Jerry's routine takes 1768 us, to be precise.

73 Allard PE1NWL

Sorry, folks - a typo slipped past me. 2 1/2" by 1/2" :)

73...

Re: inductive resistors.

Raj's resistors are the 'norm' and have been for a long time. Carbon-rod resistors (non-inductive) went out of fashion in the 1940s, but they were the standard until then. Their manufacture was by baking the rod (with its leads), so it was very imprecise. Their value color-coding (the original) was body-end-dot so there was no tolerance value - it was generally assumed to be 20%. Power rating was by physical size, (as it still is) so the smallest common size ended up about 3/4"long by 3/16" diameter.The biggest ones in my 'junk box' are 2 1/2" by 1.2". As commercial use of higher frequencies progressed, the physical size and tag-strip construction became a limiting factor, so axial leads were developed with color bands, tolerance band, extra decimal value ...

Non-inductive resistors are made these days by grooving from each end in counter-sense (like a turnbuckle's threads), but they're rare and expensive. I have seen a lengthwise cross-section of a high-power RF dummy-load, and its manufacture was a mystery to me - intriguing, but I hadn't the time to study it.

Just FYI ...
73 de ZL2DEX

Digging up this old topic. I was testing out the mic on my in-progress bitx40 build and noticed a very loud chirp when activating PTT. Has anyone attempted and confirmed the fix proposed by Gian?

Thanks!
David

If you have a linear taper pot, you can approximate a audio taper by adding a resistor from ground to the wiper.? A value about 20% of the resistance of the pot comes very close.
--
DuWayne? KV4QB

Did you remember to install the capacitor on the Tuning Pot ??? ?That would do it.?

Also if you upgrade to Allards sketch you get improved tuning stability plus with the PTT Sense mod
it will prevent ?the VFO from changing frequency during TX so that will eliminate any "FM-ing" on TX.

Cheers

Michael VE3WMB?

Hi Raj,

What I am reading on the internet on simular designs is that if the opamp supply voltage is low, in my case a bit more then 5v, it seems others have encountered simular problems as what I am seeing.?

From:?https://www.riyas.org/2015/04/a-simple-standalone-antenna-analyzer-with-ili9341tft.html

If the SWR rolled up at the higher frequencies, it means the buffer is not working well

Seems to be the exact thing I am seeing on mine. Rechecked the buck-converter as well again and it is very close to 6,6V

Hmm on we go.,

Thanks and regards,

?

Leo

Do you mean like this?

?

Hi Raj,

Ah yes you are right well I will do some further experimenting I guess. Still trying to understand why at the lower frequencies it is behaving just fine for the VSWR but towards the end ie 10m it is not. Maybe it could have something to do with the ad9850 DDS as far as I am aware it might be slightly off on the higher frequences?

I have some very tiny coax lying around so will solder that onto it and also I have a 50 Ohm chip resistor at hand also so plenty to experiment left ;-)

regards
Leo

Leo,

A resistor is an inductance too. A conductive resistive film on a ceramic rod is spirally grooved to give a final value.
Typically a 1 -5 Ohm blank is grooved to produce a 50 Ohm resistor. I used to run a factory makng them!

What I meant was interconnect RF wires must be coax in a build. I haven't built this project myself.

Raj

Hi Raj,

Not entirely sure what you mean by connecting the board DDS and ANT to the external BNC? We even see the same responses with a resistor directly soldered onto the board pads for ANT ?

regards,

Leo

True, and I feel fortunate to have both options available - 1. a full featured library that will do whatever you need to do and 2. streamlined code designed for this particular task.?

Looks like a good one.

Try using a 50 Ohm thin coax like RG174 to connect from board DDS and ANT to the external BNC connectors.

Raj

At 10-11-2017, you wrote:

Hi Raj,

Thanks for your input, wel even with a 100 Ohm resistor soldered directly onto the antennapads of the analyzer(so should be about 1:2) results on both my analyzer and that of my friend are the same. The dummy load is very close to 50 Ohms as well by the way. I have attached a photo of it by I seriously doubt the dummyload or its connectors are at fault here. Really weird things going on for sure...



It is a 50 Ohm dummyload btw capable of 100W/250w PEP.

BFO end, not VFO?