6 Meters on 690?

[kk6rq]

Has anyone managed to get a 690 to work in the 6 meter band? I've
got 90% of the way there, but am stuck on one thing--

I've figured out how to get the OOB freqs in, adjusting the VCO,
as well as any necessary tuning but the radio seems to have a
block as to TX above 50 MHz (50.00 works, 50.05 and higher does
not)
As I got it, it locks to somewhere below 36.0 MHz and allows input
w/o hacking down to 29.7.
I'm thinking I need to delve into the firmware. Anybody made any
headway with one of these?

[Birken Vogt]

What we did is to go into the data file, program all the freqs that you want to be in the ham band say you wanted 52.72 MC, well program it in the program as 42.72. Then open up the data (.DAT) file with a hex editor and you will find the freqs stored in there in a strange format, it is like 072 042 or maybe even stranger, whatever it is, it is backwards (doing this from memory) so program lots of freqs of the same thing so you can spot them and learn how to edit the data file. (We always have used the DOS program)

Once you have that figured out you will have the program done, then blow the programming into your radio, now we found that the VCO needs tweaking of course. But we have not perfected the finals yet, they seem to be smoking an inductor on transmit. I will get back to you on that.

I really like the 90 series radio. I hope somebody smarter than me can figure out how to hack the editor program itself so we don't have to go through all this hassle

Birken

[kk6rq]

Nah, programming isn't a problem--I was concerned that 6m was physically locked out in the firmware because 50.00MHz works but 50.05 and above does not; that seems WAY to precise a freq to arbitrarily be the cutoff naturally. If you say yours works though, I'll see what happens when we attack the VCO lock when I get access to a service monitor.
The overheating you're experiencing sounds like an LC circuit in the lowpass filter. I used to get that on LB GE Rangrs. All that should need to be done is someone savvy look at the manual and recalculate the tuned circuit.

[kwradioguy]

Please excuse me if I am asking an obvious question, but you do have a Type 3 radio?

Type 1= 29.7 ~37.0 MHz ALH22923110
Type 2= 35.0 ~ 43.0 MHz ALH22923120
Type 3= 40.0 ~ 50.0 MHz ALH22923130

The FCC ID for the radio that "could" go on 6 Meters is listed above. If you have a Type 1 radio, it would be used on 10 Meters.

The silver label on the back of the heat sink should list the ID for the radio.

I don't think you can pull a Type 1 radio much above 38 or 39 MHz.

Regards

[kk6rq]

Yes, its a 40-50 type 3.

[Birken Vogt]

I came across some instructions to put a slug (we used 12ga solid copper wire about as long as it was big around) in the inductors of the VCO but that did not seem to help, it was too unstable glued in there on a vehicle that bounces around and we discovered it was not necessary, it could be done by just tweaking. But yes it does seem to cut off at exactly 50 MC but it's all in the tweaking.

No the inductor that burned up was not in the LPF but my friend tells me those inductors have been getting pretty hot so it would probably be good to fix that too. We have very limited experimentation with this so far.

The inductor that burned up was L1, 1uH. FWIW. He said this radio had been having problems before though at 43 MC but he changed the whole PA board. Not very much data to work with.

Birken