Monday, October 26, 2015

FT-707 repair (11) un-converting from CB to 10m

One of the FT-707's that I aquired recently had the CB conversion on band 10A to 10D, that is the allowed CB band in most countries and also the pirates low's and highs spread accross the 10A to 10D band switch.

The hardest part here was finding the right Crystals, the few that Yaesu dealers still have in stock are extremaly expensive.

I had sorted that a regular 14.318 computer crystal would work on the 10m B position (oscillating at 42 .954), very near the 42.987 as standard on the radio.

Here's the local oscillator table for 10m

Now I acquired some less expensive crystals very near the factory frequency and can get coverage from 27.9Mhz to 30Mhz (less 79Khz in the end) on the four segments covering all the 10m band plan.

Low part on the 10A position:

High part on the 10D:

Now it's a true amateur radio, not a CB one.

Since the pin's on the new crystals were larger than the existing ones I made some terminal adaptation, that's why they are higher than the one in the 10mB place, second from the left.

I needed to put new coils (new cores and rewound) for 10mA and B, due to previous expert that touched the radio, that was covered in a previous post.

Crystals used were these ones:

10m A - 42.444 Mhz
10m B - 14.318 Mhz (on the overtone)
10m C - 43.444 Mhz
10m D - 43.888 Mhz

Have a nice week!

Saturday, October 24, 2015

"New" equipment - Yaesu YR-901, YK-901 and Heathkit SB-610

..New as in new for me. Last August I bough this pieces of "furniture" for the shack, I know the post is a bit late, it's already October.
Only bough them because it was relatively inexpensive, so worst case scenario (they don't work) the box's will be used for some other project, I didn't tested yet, the decoder YR-901 looks ok, the SB-610 has some changes on the CRT tube connections so will be tested first with a bulb inline and after a small revision.
Here's some images for your viewing pleasure.

YR-901 CW/RTTY decoder:

With the matching keyboard, YK-901:

SB-610 Oscilloscope, transmitter monitor:

The YR-901 decoder will be a nice addition to the FT-102 Line:

...Have a nice weekend!

Sunday, October 04, 2015

More filters

Some time ago I bought 3 isolated filters, one LSB, one USB and the other for AM, the idea is to use them as secondary filter for the "Trevo"....or maybe for some other project.

This time I bought another set, including the board where they all seen to come from. It looks some sort or IF part of a radio, it has the MC1350, MC1496 for SSB/mixing/amplifying. Just can't find any reference about the board.

Anyhow, the idea is to remove the filters the IC's and parts for other projects.

It's cheaper to buy the 3 filters than a single one from a major brand, if they are good or not, that's another story.

Have a nice week!

ps: Updated here with more info

Thursday, October 01, 2015

Another kit

I always liked planes, when I was a kid my father was a plane maintenance mechanic, althoug I only went with him very few times to the hangars it was allways something that fascinated me.

Maybe one day I will try to fly one, I think planes and trains are the only transportation mean that I'm not certified to "drive"...

Passing trough the local supermarket there was some promotions on plane kit's, so why not!?
So far I've built two, one for each year that I've been in Ireland.


and 2014:

...this Year still didn't spotted the promotion...

PS: If you think it's easy to make, think again, you really need some patience to do it , tough that's no rocket science.

 Have a nice day!