Realistic TRC-465 VCO

[tecnicoloco]

Hi:

I need some help in the VCO area to stretch the range about 100 Khz up or down

I have 3 of these little SSB Radios 2 TRC-465´s and 1 453

I installed a board to get Hi Band and Low Band and works but the VCO is shy of 100khz or the last 10 channels of the Hi Band or short 10 channels in the Low Band

Also I need a good modification to open the clarifier without loosing to much stability,I know it will drift but I hope not to much

The board that I installed gives me +5 or +10 Khz and is very stable,just want to be able to make the clarifier slide 1.5 to 2 Khz up or down if possible

BTW the Board is from Austria and I have installed several of these boards in different radios and all of them works good 40 Hi and 40 Down

After I done with this I will do Handy Andy mods/PC122 for this board too


Thank you for your help
Andy

 

[NZ8N]

Easy Peasy !!

Change C72 (47p) to a higher value, like 220p (221), or 330p (331), 470p (471). This increases the range of the varactor diode in the PLL circuit. The same goes for any of the other boards like this, PC122, Cobra 146, etc...
I just looked at my PC122, I put a 220p (221) in C72.

Expo N kits are kind of odd, your USB and LSB will be off by 2.5kc when on upper or lower channels, and you would have to use the Clarifier to one side or the other to get back to center slot.

If you can find one, a Galaxy Viagra board has the correct "cans" to offset the upper frequency crystal and lower frequency crystal to put USB and LSB back on center slot, 3 cans each crystal.

Austria board you say? Which from where?

 

[NZ8N]

I cut the trace to the high side of the Clarifier, rather than tracing back through the ribbon cable. It was a LOOOONG time ago, and this is/was one of my "experiment on" radios. I have a Galaxy Viagra A board in it for a test I was going to do, Blue Dot, with standard 40 up and 40 down in it.
The red wire to the high side of the Clarifier goes to the corner trace of the main board in the 2nd picture. I think it is 8v constant. The blue wire to the Clarifier center pin goes to the Clarifier input on the Viagra board so the Viagra board can slide as well.
I haven't hooked this radio up in forever, so I can't remember how much it slid up or down. Dusty!!

Here is the Viagra A board in my PC122
I bought a couple of Blue dots boards, a couple of Green dots, a Red dot, and a Viagra B board, which has a PLL set up to do the offsets. From RF Parts about 12 years ago.

 

[tecnicoloco]

Wow you make my day NZ8N Big Thank You for your great help Sir

I bought over 25 boards in the last 6 or 7 years from Ing Maurer

http://funkservice.at/en_pll-modul.htm

For PLL 03A,MB8719,CC1301.UPD858,UPD861,TC91019.TC9106,LC7131 and UPD28xx and for others that I don´t remember

40 Low Band,40 High Band,+5 and +10 Khz within the radio bandwidth

Now with this virus deal I been grounded from work for the last 4 months and to kill time besides household chores I get more time to talk and play with my radios

Also with your recommendation on the Uniden Grant the radio is working spot on frequency


Happy Four of July
73 de Andy

 

[Handy Andy]

I was only going to add that if you have a SPARE Varactor - you can piggy it at D19 by C72 - the radio tuning sees the Varactor as an "extra capacitance" and seems to tune well using it. At least it tracks in the Grant (8719) I use it in.

For PC-122 it's By D19​

I use the "extra Varactor" simply from the older days of Galaxy using the SVC251 paired they used - using one along with the original of the'122's and the extra didn't seem to affect the PLL in it's ability to tune to the needed "lock" frequency.

The only thing I hesitate on, is the LACK of discrete Varactors - seems they dried up - so the SMD types are a little trickier to work with. The Mod I did was for the Grant to simply use the "jumper switch" mod to make oddballs for a (former) friend.

 

[tecnicoloco]

Hi Handy Andy

Thank you for your input in my quest

Yes I have extra varactors too SVC251 and BB809 axial type,lucky me I got then over 10 years ago


Happy Four of July
73 de Andy