Maratrac Low band conversion to 6 meter

RFNebraska · Post by **RFNebraska** » Thu Mar 24, 2005 4:23 pm

I have a low band Maratrac (42-50) that I'm toying with the idea of doing the conversion to 6 meters with. How do I preform this opperation? Is it a hardware mod or simply a software adjustment. I have access to the RSS for this radio.

RFNebraska

Bob · Post by **Bob** » Thu Mar 24, 2005 5:39 pm

This is discussed on the model-specific page for the maratrac on batlabs.com

http://www.batlabs.com/maratrac.html

Also consider reviewing the maxtrac page, as the maratrac and maxtrac are similar radios.

Max-trac · Post by **Max-trac** » Thu Mar 24, 2005 7:07 pm

Hack RSS to allow freqs per batlabs.
Turn VCOs counterclockwise as necessary for your highest freq.
Check power out and sensitivity, it should be acceptable, but they are all a little different.

RFNebraska · Post by **RFNebraska** » Thu Mar 24, 2005 7:58 pm

Thanks, judging by the link Bob provided to me it looks like its a little more trouble than its worth..... still the radios just sitting there in great shape.... seems like a waste to just let it sit here.... I may have to do some more RSS research.

JIM

Max-trac · Post by **Max-trac** » Fri Mar 25, 2005 8:51 am

I think you will have satisfactory results without all the component changes mentioned on batlabs.
Just make sure you are starting with a high split radio....

phrawg · Post by **phrawg** » Fri Mar 25, 2005 9:56 am

I have moved a handful of them to 6 meters. No, you do not have to
do all of the component changes. You DO have to edit the rss
to allow the freq entry, then the vco's need to be tweaked to
a range that works. Usually I just program about 47.00 Mhz in and
set the vco to the low freq edge (about .8 to 1.0 volts) in each of
the circuits (tx and rx) and the high end of 7-8 volts will fall at
about 55 mhz which is fine. Then take several 10-32 BRASS screws
and start filling the rx front end coils with them as needed.
Many times the slug will make things worse in some coils.
Sometimes 2 or 3 slugs in just the right coils will do the job.
Put in and take out in different coil combos for the best performance
on receive. On xmit, use a soft nylon or plastic wide screwdriver
point to push between turns in the pa deck heavy coils to spread
them just a bit and do so where necessary to peak it. THEN,
go into the service alignment of the rss and find the 16 freq points
to set the power and re-do all of those adjustments treating
the 47-55 Mhz spread as tho it was 42-50. To do this I program
47,48,49. . . . ,55 and work through them to balance the output
across the new range. I can always get at least 95 watts anywhere
by doing it this way. Rec is .30 Uv or better also. Not a big job.
takes me about 3/4 to an hour to do one completely.
Hope this helps. Phrawg

jistabout · Post by **jistabout** » Fri Mar 25, 2005 12:47 pm

Greetings Earthlings....

I just converted one last week........

All I did after programming with modified RSS was to monitor the SL point on the RF board and turn the VCO coil slugs slowly counterclockwise until obtaining the required voltages.

According to my HP signal gen and audio voltmeter, RX sensitivity is .29uv for 20db of quieting. I was pleasantly surprised...

I didn't accurately measure TX power, but it will peg the needle on a 60w bird termaline, so its more than 60 watts.

Good luck. Should be an easy conversion.