Yaesu FT897D and DSD

Status
Not open for further replies.

ko6jw_2

Member
Premium Subscriber
Joined
May 18, 2008
Messages
1,069
Location
Santa Ynez, CA
Some issues:
The digital modes that the Ft-897D can use out of the box are SSB AFSK modes.
You would have to modify the radio to have a discriminator output to receive FM based digital modes.
The frequency coverage of the receiver does not cover all public safety bands.
It could not scan trunked systems.

A dedicated scanner is almost always a better way to go to scan public safety.
 

KE5YOU

Member
Joined
Dec 30, 2008
Messages
45
The recieve range on the 857D DOES include public safety bands. Interesting thought to run the radio through a DSD. I would make an intresting project. However the radio still would not be able to monitor a trunked system.
 

KE5YOU

Member
Joined
Dec 30, 2008
Messages
45
For the given frequency range of the radio it DOES cover public safety bands. I pickup my employer with mine (Conventional UHF system) with mine. Although you are right. The radio does offer ANY coverage in the 800/900 MHz range. That is like asking how well a fish climbs a tree.
 

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
23,242
Location
Bowie, Md.
Some issues:
The digital modes that the Ft-897D can use out of the box are SSB AFSK modes.
You would have to modify the radio to have a discriminator output to receive FM based digital modes.
The frequency coverage of the receiver does not cover all public safety bands.
It could not scan trunked systems.

A dedicated scanner is almost always a better way to go to scan public safety.
It's possible you might not need to do any mods to the radio itself - many radios these days have a '9600 out' at the mic jack (I seem to recall that some radios actually have a separate jack for this) to be used for TNCs. It would take some doing to see if that output is connected to the discriminator; if it is, you're half way home. Mike
 

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
23,242
Location
Bowie, Md.
It would appear that the 897 has a 'DATA' jack on the back with a 9600 out on a mini DIN - the pic from the user guide is a rather poor quality, but it's shown here...

Yaesu FT-897D Rear Panel

According to the DSD article, someone has done this exact same thing with the 857 so at least in theory, it is possible....

Mike
 
Last edited:

ko6jw_2

Member
Premium Subscriber
Joined
May 18, 2008
Messages
1,069
Location
Santa Ynez, CA
Pin 5 on the DIN connector is the hot audio out (I know it says 1200 baud). Since this is intended for SSB AFSK digital modes, I'm not sure this will work as an output in FM for P25 and at what point it would be connected in the receiver. It is a fixed level audio output at a line level so it needs an attenuator to connect to a mic input. The pin outs are the same for 817, 857 and 897. FT100D too. I need to get a DIN connector to test.
 

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
23,242
Location
Bowie, Md.
According to the pic, there is a 9600 baud output on the other side of the jack. It's kinda hard to see to be sure, but that may be a better bet for a discriminator output than the 1200 baud connection

Mike
 

ko6jw_2

Member
Premium Subscriber
Joined
May 18, 2008
Messages
1,069
Location
Santa Ynez, CA
There would be no reason to have a discriminator output for packet or APRS digital modes used by ham radio operators. In fact it would probably be better not to use the discriminator output. The digital mode on the radio is SSB and would come from the product detector not a discriminator. The 1200 baud audio output would be sufficient because HF digital modes don't require high baud rates. The whole discussion is about how to use a radio in a way it was never intended to be used. It may be fun to speculate, but a really good scanner is way less than an FT-897D and is designed to receive digital modes and trunked systems.

I own both an FT-897D and an FT-817ND not to mention an FT-100D. My information on the pin outs and their uses come from hams who use digital modes like RTTY and PSK31 etc. I have really good pictures of the pin outs because I have the original manuals.
 

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
23,242
Location
Bowie, Md.
I'd be willing to wager that the individual who got his 857 to work with DSD hooked it up to the DATA 9600 baud pin - remember we're talking about VHF and UHF here, not HF. And the 897 does cover the VHF hi and UHF bands. I have my doubts that the 1200 baud output will work, but I could be wrong - I suspect most of the modes used by DSD use data signalling faster than 1200. And here's the key point -otherwise you wouldn't need a discriminator tap from a scanner to run this software (and if you're using a scanner like say the BC780 or a PRO-163, you most defintely do)

With a good soldering station I suspect it's easy enough to move the connection from the 1200 baud pin if you find it doesn't work.....

Mike
 
Last edited:

ko6jw_2

Member
Premium Subscriber
Joined
May 18, 2008
Messages
1,069
Location
Santa Ynez, CA
If pin 5 is, in fact, a discriminator output in the FM mode, there is no baud rate. It's just audio. You then use external hardware and software to demodulate an FM based signal with digital information. P25 and other digital voice modes are FM. The baud rate is set by the transmitted signal and decoded externally from the radio. What the pin label says makes no difference. The only reason to use discriminator outputs is that they are not subject to FM audio de-emphasis. Packet and APRS don't care. In fact, they can be run off of headphone or speaker audio.

The only P25 signals in this area, that are not trunked and in the 460Mhz range, are encrypted. The only unencrypted P25 signals I have ever monitored are in the 700-800Mhz bands. Your situation may be different.
 
Status
Not open for further replies.
Top