Vertex VX4000L - 29 MHz out of band mod

[g8tzl2004]

I'm looking to program a low band 29.7 - 37 MHz Vertex VX4000L onto 10m

The lower band limit is currently 29.7 MHz.

Anybody done the mod?

I've read up about the 440MHz VX4000 mod but when I try and "find" the 29.7 MHz band limits using a hex editor I'm having no luck...although the procedure works OK on 440MHz. I've tried a number of combinations of "297000....." but there is no hex match.

Any ideas?

[escomm]

29700000?

[g8tzl2004]

Sadly No.

I've tried every combination of 297 to 297000000 as well as 37 to 3700000000 but no hex match

I checked out the 450 MHz "codeplug" and did get a hex match using 450000000 so the low band radio must be different.

The default limits are definitely 29.7 and 37 MHz

[KE7JFF]

If I remember right, the other band limits should be nearby the 450 frequency...

[g8tzl2004]

As I understand it, the hex editing involves editing default.c49 "codeplugs" which are frequency specific - so the 29.7MHz codeplug is just for Low Band and contains no 450 MHz data.

I did look for Low Band band limits in the same location as the 450 MHz band limits but there was nothing that seemed to make sense.

I'm hoping that I can find somebody who has previously successfully modded a 10m or 6m VX4000.

[g8tzl2004]

Well I've successfully programmed my low band VX4000.

The issue was that the decimal to hex converter did not include a "zero" at the start of the 29.7 Hex value - it should have been 01C52FA0 rather than just 1C52FA0. I added the zero and it all worked. You simply have to remember that the Vertex software uses 8 hex digits for the band limits. If the hex converter only gives 7 digits, then add a zero to the start.

Only problem now if that the VX4000 works great on 29.660 and above but is completely deaf below 29.660MHz - sensitivity seems to fall off a cliff rather than a gentle decline. I guess the band pass filters need adjusting.

So has anybody ever aligned a VX4000 or VX5500 or VX6000?

[KE7JFF]

Yeah...I found my old text file notes that made mention of the leading zero in the hex frequency.

[g8tzl2004]

Did you ever align your VX4000?

[KE7JFF]

Did you ever align your VX4000?

I had a hi-band VHF one for a bit I had a friend align; he had no issue with it as I recall.