rfrht / ft991a-pat Goto Github PK

ISSUE
Currently, the board sorely lacks a few test pads for testing and signal measurement.

ENVIRONMENT
All boards, through Revision N

RESOLUTION
Implement Test Pads in a few critical points.

ISSUE
Currently, the panadapter does not tap the signal by default - It only opens to the signal upon the presence of both RX_EN and RX_9 signals. Enabling a GPIO line to open the panadapter is just too clumsy, requires external software and is not friendly at all.

ENVIRONMENT
All revisions through N.

BACKGROUND
When projecting the board, it was unknown on how adversely would it affect the signal on the radio, thus I decided to keep it off by default. However, I found no signal degradation.

RESOLUTION
Change the Off by Default RF switch configuration to On by Default.
Change the logic AND IC to a "OR" IC
Change the radio signal tap from RX9 to TX9.
Thus the switch will flip to ground the signal with either the presence of GPIO or TX9.

Workaround
Solder a 3V line to the RX_EN signal from the NCP553 regulator output.

During the Rev. O test, was found an unwanted input signal attenuation when the board is in TX9/Disable mode - The problem is thoroughly described in the wiki article

The board must not cause any significant input signal attenuation, especially when in TX9/Disable mode.

ISSUE
Provide a fuse on the board for extra protection.

ENVIRONMENT
All revisions through N.

BACKGROUND
Currently, the Panadapter board sits behind a 3.5A fuse in the Main Unit. This is just too much.
The panadapter draws around 10 mA typical in the 13.8V line.

RESOLUTION
Implement a 20 mA PTC fuse.

The part MMBFJ310CT-ND is marked as an obsolete item on Digi-key.

There are three suggested substitutes: MMBFJ310LT1G, MMBFU310LT1G, and MMBFJ310LT3G.

The footprint looks same. Could you take a look which one will be a good direct replacement?

Originally posted by @wgxdz in #12 (comment)

ISSUE
As per testing in Revision N, the selectable band-pass filter does not work - Matter of fact, it kills entirely the signal, from 1-900 MHz.

ENVIRONMENT
Revision N.

RESOLUTION
As of now this is not of super big concern, because the BPF is turned off by default.

Two possible resolutions;

1. Removing it entirely;
2. Implementing a good design.

There's a clear mismatch in BFR193 (see #25) which is hindering its full possible power.
Research a matching network (via trial and error) that can obtain a proper gain figure from this transistor.

On the page

https://github.com/rfrht/FT991A-PAT/wiki/installation

the image link for the TX9 tap point located at

https://github.com/rfrht/FT991A-PAT/blob/PAT-Light/Design/tx9.jpg

is missing.

• Better Silk-Screen Pin 1 markings for Power regulators
• Larger footprint for 2SC5086
• Moving 0.1µF transistor caps away from RF section
• Lots of re-routing
• Changing 1 nF caps to Low ESL type and 0805 footprint for better RF performance
• Labeled a few signals in Eagle file for better understanding of signal route/path

In the SHIFT menu item description, RX or TX field (see below), it should say RX, not TX:

SHIFT

WHAT: The shift function "shifts" (doh again) your receiving bandpass to above or below (or left or right), removing either the bass or treble part of the signal depending to the direction that you set the shift - narrowing the received signal.
AVAILABLE OPTIONS: -1200 Hz to +1200 Hz. 0 means no shift, disabled. Set with "Multi" encoder.
**_RX or TX? TX_**
WHICH MODE? AM, SSB, CW
WHEN TO USE: The primary use is to defend from an adjacent signal over the lower or higher edge of your receiving signal. Use shift to dodge this interfering signal.
CAVEAT: This is also useful to make the receiving less tiring, irrespective of having or not an interfering signal - Try using Shift between -600 and -200 together with DNR - I promise you will love it!

Hi, thank you (and W3AXL, and OE2DOR) for designing this awesome board and sharing it with us!

I've ordered my PCBs from OSHPark, but discovered that five of the components on the BOM are not available, due to general supply chain insanity (which has been going on for a couple of years now...).

I went ahead and ordered from Digikey anyways, with the following four replacements; do you think these choices will work? If not, can you suggest better substitutions?

• MC78L09ABDR2GOSCT-ND -> 296-11126-5-ND
• NCP553SQ30T1GOSCT-ND -> 1662-1980-1-ND
• MMBFJ310LT1GOSCT-ND -> MMBFJ211CT-ND
• 2SC5086-OLFCT-ND -> BFR106E6327HTSA1CT-ND

The real problem, however, is USB2514BI-AEZG-CT-ND. That is total unobtanium right now, Digikey is showing an 18-month lead time. And it isn't a commodity part. Any ideas about what to do here? Should I try buying an old USB hub on eBay and scavenging from it? Any ideas which high-volume products might have used this IC?

Thanks again,

Procure board, components and assemble it

ISSUE
The board only comes to life with a PAT_ENABLE signal. This requires a Voltage regulator with a Enable signal and extra wiring on the radio.

BACKGROUND
Originally, the project intended to also power the SDR dongle. However, I found that when feeding the SDR through the Panadapter board, the 9V regulator gets real hot.
The radio is designed to run cold, as hot environment adds more noise to the sensible transistors/amplifiers in the RX stage. At this point, a selectable "Enable" made sense.
However, starting with Revision N, the SDR is powered by the +5V bus on the radio, straight from a 1.5A LDO which is properly attached to the aluminum chassis for proper heat dissipation.

ENVIRONMENT
All Revisions through N.

RESOLUTION
Use a smaller and cheaper 9V LDO.

As a workaround, wire directly the 13.8 Vin to the PAT_ENABLE pad.

As per Digi-Key announcement:

It is a 50 mA :-P

Resistors R5, R7 and R10 are essentially attenuators in RF lines - this was blindly copied from the original G4HUP project, with no test of what's the effect in gain output.

As per G4HUP statement in his project description:

[...]and a resistive attenuator to allow the overall gain of the board to be matched to the input requirements of the SDR.

Will test in a VNA what's the effect of these transistors, especially the R5 which can cause an attenuation in the input signal.

Looking at https://github.com/rfrht/FT991A-PAT/wiki/installation#tx9 and comparing the image to my 991 non-A, it appears that the highlighted section is not present on my radio. Might it be possible to point me toward an alternate location to tap the TX9?

Here's an photo from the same section on my radio, in case I'm just not seeing it.

Thanks

hello,

Thank you for this project, great work, I like the integration in the FT-991A.
I realized the S revision with the BRF193F, but I have a gain problem.
The gain is around -20db, I changed the BFR193F but the same.

I tested in the FT-991A but the attenuation is too high with IPO or AMP1 the signals are almost invisible with AMP2 I see the signals.

Do you have an idea of my problem? Is the new BFR193F transistor not suitable?

Thanks.
73.

The existing 9V regulator is just overkill - Change to something simpler.

Revision R Lite/Full just went published.

Need to:

1. Procure the 0805 capacitors
2. Procure the boards
3. Test the new board
4. If results are sound, update the Wiki Testing section and Promote Rev. R to Master

Hi
It look like there are images missing in the description regarding replacing the main USB controller.

br
Claus