I've tried unsuccessfully to decode using the 9600 b output of my FT-857 into a sound card.
The manual for Foxtelem refers to pulling the discriminator signal out of the Yaesu FT-736R for decoding. However, it does not suggest a point on the circuit. I'm thinking to try between Q20 and Q21 on the RX unit. perhaps a 0.1 uf cap to the collector of Q20? Has anybody else tried this? Thanks, Tom, NH6Y
Tom, you're really testing my memory, but I just can't remember the mod exactly. I did this mod 15 years ago to a 736 I owned at the time. All I can say is it does work at 9k6 when done. I'm sure the mod is out there somewhere.
BWTM
I did find this and I'm 100% sure it's what I did. What a great blast from the past. Good luck...
--------------------------- by James Miller G3RUH
These notes tell you where to get FM RX audio direct from the discriminator, and where to modulate the FM TX varactor directly. These mods are non-destructive and take no more than a few minutes. The signals bypass the "DATA SOCKET" for high grade FM operations.
The RX mod is suitable for:
* UOSAT-D 9600 baud downlink and terrestrial links * 1200 baud AFSK/FM Standard Packet - BUT IT'S UNSQUELCHED.
The TX mod is suitable for:
* FO-20/PACSAT uplink (1200 bps Manchester FM) * UOSAT-D 9600 baud uplink direct FSK and terrestrial links * 1200 baud AFSK/FM Standard Packet.
---****---
FT736 - FM Direct from Discriminator ------------------------------------- Detected FM direct from the receiver discriminator is available from the RX UNIT at the junction of R91 and C83. These components are shown in the top right-hand corner of the schematic.
Proceed thus: 1. Disconnect FT736 from the mains electricity. (Safety). 2. Remove top cover only. 3. RX Unit is the vertical module on the left. 4. Locate R91 which is about 25mm from the top, 50mm from the radio rear. the resistor is "on-end", and near a couple of glass diodes. 5. Scrape any paint off R91's free end and wet with solder. 6. Your RXaudio lead should be a fine screened cable; connect the inner to R91, and the outer braid to a ground point (e.g. can of TO09) 7. Route the cable out though any convenient aperture in the case. 8. The discriminator sensitivity (FM Normal) as about 6 kHz/volt.
The link....
ftp://ftp.tapr.org/general/9600baud/96man2x0.txt
73 Jeff kb2m
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tom Worthington Sent: Wednesday, October 14, 2015 14:02 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Foxtelem and FT-736R
The manual for Foxtelem refers to pulling the discriminator signal out of the Yaesu FT-736R for decoding. However, it does not suggest a point on the circuit. I'm thinking to try between Q20 and Q21 on the RX unit. perhaps a 0.1 uf cap to the collector of Q20? Has anybody else tried this? Thanks, Tom, NH6Y
Thanks Jim 73 and Aloha, Tom, NH6Y
On 10/14/2015 12:04 PM, kb2m@arrl.net wrote:
Tom, you're really testing my memory, but I just can't remember the mod exactly. I did this mod 15 years ago to a 736 I owned at the time. All I can say is it does work at 9k6 when done. I'm sure the mod is out there somewhere.
BWTM
I did find this and I'm 100% sure it's what I did. What a great blast from the past. Good luck...
--------------------------- by James Miller G3RUHThese notes tell you where to get FM RX audio direct from the discriminator, and where to modulate the FM TX varactor directly. These mods are non-destructive and take no more than a few minutes. The signals bypass the "DATA SOCKET" for high grade FM operations.
The RX mod is suitable for:
- UOSAT-D 9600 baud downlink and terrestrial links
- 1200 baud AFSK/FM Standard Packet - BUT IT'S UNSQUELCHED.
The TX mod is suitable for:
FO-20/PACSAT uplink (1200 bps Manchester FM)
UOSAT-D 9600 baud uplink direct FSK and terrestrial links
1200 baud AFSK/FM Standard Packet.
---****---FT736 - FM Direct from Discriminator
Detected FM direct from the receiver discriminator is available from the RX UNIT at the junction of R91 and C83. These components are shown in the top right-hand corner of the schematic.
Proceed thus:
- Disconnect FT736 from the mains electricity. (Safety).
- Remove top cover only.
- RX Unit is the vertical module on the left.
- Locate R91 which is about 25mm from the top, 50mm from the
radio rear. the resistor is "on-end", and near a couple of glass diodes. 5. Scrape any paint off R91's free end and wet with solder. 6. Your RXaudio lead should be a fine screened cable; connect the inner to R91, and the outer braid to a ground point (e.g. can of TO09) 7. Route the cable out though any convenient aperture in the case. 8. The discriminator sensitivity (FM Normal) as about 6 kHz/volt.
The link....
ftp://ftp.tapr.org/general/9600baud/96man2x0.txt
73 Jeff kb2m
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tom Worthington Sent: Wednesday, October 14, 2015 14:02 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Foxtelem and FT-736R
The manual for Foxtelem refers to pulling the discriminator signal out of the Yaesu FT-736R for decoding. However, it does not suggest a point on the circuit. I'm thinking to try between Q20 and Q21 on the RX unit. perhaps a 0.1 uf cap to the collector of Q20? Has anybody else tried this? Thanks, Tom, NH6Y
On 15/10/2015 5:01 AM, Tom Worthington wrote:
I've tried unsuccessfully to decode using the 9600 b output of my FT-857 into a sound card.
The manual for Foxtelem refers to pulling the discriminator signal out of the Yaesu FT-736R for decoding. However, it does not suggest a point on the circuit. I'm thinking to try between Q20 and Q21 on the RX unit. perhaps a 0.1 uf cap to the collector of Q20? Has anybody else tried this?
Can't help off the top of my head, but ig you google for D-STAR on FT-736R, you will find mods that will allow true 9600 operation (D-STAR has similar requirements).
You'll just need to do the Rx side of the mods for telemetry decoding, but doing Tx as well will give you more options in the future.
Yes, it is the G3RUH mod and there is a least one site that shows you in pictures where to solder the wire as I remember. I did this about a year ago when I was first testing the software. I get great decodes from the FT-736R this way.
Use an old headphones cable with the earbuds cutoff as the wire. Then you have a plug ready to connect to your soundcard! If you have a choice use Line In rather than Mic on the computer.
Good luck!
73 Chris
On Wed, Oct 14, 2015 at 8:40 PM, Tony Langdon vk3jed@gmail.com wrote:
On 15/10/2015 5:01 AM, Tom Worthington wrote:
I've tried unsuccessfully to decode using the 9600 b output of my FT-857 into a sound card.
The manual for Foxtelem refers to pulling the discriminator signal out of the Yaesu FT-736R for decoding. However, it does not suggest a point on the circuit. I'm thinking to try between Q20 and Q21 on the RX unit. perhaps a 0.1 uf cap to the collector of Q20? Has anybody else tried this?
Can't help off the top of my head, but ig you google for D-STAR on FT-736R, you will find mods that will allow true 9600 operation (D-STAR has similar requirements).
You'll just need to do the Rx side of the mods for telemetry decoding, but doing Tx as well will give you more options in the future.
-- 73 de Tony VK3JED/VK3IRL http://vkradio.com _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
participants (4)
-
Chris Thompson -
kb2m＠arrl.net -
Tom Worthington -
Tony Langdon