Any interest in a transverter for the LOW bands?

[VK3XDK]

Thanks to all those that have shown interest,
I'll go through the postings and send emails (and/ or post to entire group) when Ive finally got the parts available.
This has been a "something different" project and have tried to show the whole workings in its progress (hope that some or many have found it interesting?)
It has also made me realize how much electronics I've forgotten! In some ways Microwave is easier! (more and easier to use info is given with components!)

I also continue to find small improvements, its easy to play when one can "stick" leaded components here and there!)

There is a noticeable lack of 475khz (600m) circuits on the internet, I hope this circuit appears fairly soon.

I have got around 20 PCB's here, If interests continue I will get another "run".

[VK3XL]

Yep... I'm interested in a kit as well. Been following this thread since it started and have had some success on rx on 600 m already with my existing HF gear.

[VK3XDK]

Here is a suitable (very basic) switching circuit to suit the transverter.
TO-126 case PNP (BD140 ect.) transistors are good, they can easily be glued to the side of the relay.

DC and RF are switched by one relay, simple but effective on the lower bands. (try to keep rf wires short in length)

[VK3XDK]

Pictures tell a thousand words??

[VK3XDK]

Output displays. (30db attenuator in line)

[VK3XDK]

I have made some more changes! (schematic "edited" in former post)

changes include,

Bias change on RX device (to reduce current and heat) (120R increased to 150R)

Bias change on 475Khz TX/RX diode to improve intermod. performance (1.2K lowered to 1K)
Bias change on 475Khz TX/RX diode to improve intermod. performance (1K lowered to 560R)

Bias change on SGA5586 (130R raised to 150R) this resistor needs to dissipate 0.6W! Im looking at upsizing to 2512 type resistors.

Bias adjustment on TX output device (IRF520) reduce trimmer setting to 100 - 400ma Idle current. Reduces heat.

Pi Filter implemented on "CMOS" oscillator output, cleans up the LO and reduces oscillator current.

Diode type and trimmer values now added.

Sorry about the changes!

[VK3XDK]

Im also thinking of thermal compensation on the output device's bias.
It doesnt need it in a typical application, but may save the device in an accident (none of us have these- do we? )

Im up for easy ideas (to save me work and research!), im thinking a thermistor instead of the 1K resistor to gnd.

[VK3XDK]

I have had a couple of inquiries on how to open the "TIF" file (schematics and layout)

It is as simple as Right (mouse) clicking on the TIF file (the attachment) and choosing "view image" in the menu that appears.

[VK5AKK]

Still can't view the TIFF.
Is it just me?
Cheers
Phil
VK5AKK

[VK5APN]

Phil

Right click on the file and "view image"

Hope that helps

Wayne

VK5APN

[VK4CDI]

I can't see em either...even right clicking etc........

Phil VK4CDI

[VK4ADC]

I have to right-click on the placeholder and use the 'Save As' function to store on my HDD, then open it from the folder I saved it in. I am using Google Chrome..

Graham, it might be better for all if you have to create your image in TIF format, subsequently open it in (Windows) Paint then immediately save it as a JPG format for adding to this forum - it will display immediately. I suspect that TIF is not natively supported by all web browsers.

[VK3XDK]

Yes Im having trouble compressing it enough (as a JPEG) to be accepted by the logger!

[VK4TI]

Yes Im having trouble compressing it enough (as a JPEG) to be accepted by the logger!

Photoshop and several other programs offer save as web .jpg

[VK3XDK]

Yes I think the logger may be playing up as well!

I tried opening the images with internet explorer (I normally use fire fox) and found that they wouldn't open! (I can see why people have had problems)

Anyway, Ive put the images on my website (should be easily available there )
http://www.vk3xdk.net46.net/1_31_600M-4 ... erter.html

[VK4TI]

Yes I think the logger may be playing up as well!

I tried opening the images with internet explorer (I normally use fire fox) and found that they wouldn't open! (I can see why people have had problems)

Anyway, Ive put the images on my website (should be easily available there )
http://www.vk3xdk.net46.net/1_31_600M-4 ... erter.html

Thank you

[VK3XDK]

OK, the long-awaited RX strip-Bandpass (selectivity) characteristics.

The analyzer is set at 10db and 200kHz per division.

The 1.064Mhz indication is the center of the sweep
The Marker is set to 472Khz.
External (and internal) attenuation has been manipulated to give a good indication of final conversion gain. (dbm becomes db)

I think most will be impressed!

[VK4ADC]

Graham

Re the size of the image files, I usually resize mine down to 500 pixels in the largest direction (ie. vert /portrait or horiz / landscape) and don't have any problems putting them onto VKLogger or other forums.

Windows Paint (if you don't have anything else) will allow you to re-size using the Stretch/Skew from the Image Menu, just make it 25% for both horiz and vert then save it as a JPG.

[VK3XDK]

Thanks Doug, Ive just started to have a go at that.

[VK3XDK]

The design (As far as I know) had it's first 2-way SSB contact last night,
VK3XDK to VK3HP (around 45Kms) on 476Khz LSB.

I was running "barefoot", around 6-8W into my 40M dipole@ 20ft. (tuned with a military style longwire tuner)
Easy contact, Thanks Grant!!!