SDR mod complete (or kind of)

My RTL-SDR stick is now inside it's tin submerged in Aldi's own brand cooking oil (other discount supermarkets are available) and it seems to work fine and drift appears to be reduced greatly, there is one issue that occurred however.

The Neutrik USB connector and BNC connector are both coated with silicone sealant underneath, though it does not react with cooking oil the connectors aren't properly sealed and leak by a small amount when the lid is pressed on, not good, to remedy this I have decided to use Sugru, which may require me to temporarily remove the lid of the can to deal with, around the outside edges of the connectors.

The stick has little noise (due to a mod to the cable between the "A" side of the Neutrik and the stick itself, the shielding of the tin, and, of course, the cooling, it is currently placed on my bedroom windowsill and connected using a high quality Belkin USB cable.

Reception wise so far, as I am temporarily utilising the Nagoya NA-771 antenna, has been GB3IR, PMR446 channel 1 (which I was using for some tests to check drift and at the same time was in use by children as is normally the case), CB channel UK19 (me again for drift tests), the PPM correction ONLY had to be reduced.

This whole idea came from SDR for Mariners and the author seems to be bang on the money here, the stick can't get that hot if in oil, refrigeration may help further.

To make the most of the SDR I will naturally need a better antenna, the NA-771 is a 2/70 antenna, meaning it is only any good in VHF and UHF frequencies, and doesn't make a good scanner antenna, so that may need rectification.

In the mean time I think it's best to stress test the stick in its new enclosure.


73 de 26CT730

SDR enclosure almost ready for stage two

Posting this on my phone as the home QTH has no Internet connectivity since Friday morning, which has resulted in no PMR446 gateway in Richmond, unfortunately this is BT's issue as opposed to mine.

I found a second nut and machine screw today while tidying up, needless to say this allowed me to drill a second hole and fasten the USB port to the tin lid properly, I removed the SDR to drill the hole as I did not want to damage it, it was returned to the tin when the second screw was tightened.

The SDR is currently tuned to GB3IR, the local 2m repeater, the antenna is a 2/70 antenna so fine for this use, performance appears to be good, the next stage will be sealant around any holes to prevent leaks, then some vegetable oil for coolant as far as I dare fill the can, as per the information on SDR for Mariners, and a final bead of silicone sealant on the outside of the lid to be absolutely sure.

This has been a slow project but it is almost there, a scanner antenna will be next for this, hopefully I can see what this cheap SDR, when surrounded by metal and immersed in oil, can really do.

73 de 26CT730

PS, I hope to have Internet restored and the gateway operational soon

President Grant 2 to be ordered soon maybe? (also a shack computer update)

I may place an order for a President Grant 2 next week if my finances look good, this will allow me to operate on SSB, in particular on my DXpedition to Tan Hill, however I will see what's what.

The reason I chose the President Grant 2 is several reasons, it is the first legal rig that allows you to switch between the new modes in the UK band (this is a recent update to the firmware in the radio), the radio is fitted with a power socket on the rear that the power lead plugs in to, this is similar to my Moonraker FA5000, a rig I hardly use now.

The President Grant 2 is easy to open up to export mode, inside there's a white wire and a jumper block, simply snip the wire and move the jumper, at the loss of your warranty and and your own risk, you also would lose the UK setting but you can get this back by moving the jumper back to it's original position.

It support's President's Liberty wireless microphone, a great idea that no one really thought of in the past, means you are not tied to sitting in the shack or your /p station, you can take a wander if you like, up to 100 meters I think it is, much like a DECT phone or a bluetooth headset.

Another nice feature of the rig is a choice of two backlight colours, orange and green, which also includes a dimmer so you're not blinding youself with a bright backlight at night.

There are other features as well on the rig but I'll do a full write up when I actually get hold of one, hopefully in a couple of weeks all being well

My shack computer has had a new motherboard, RAM, and CPU ordered for it, this would help with performance with regards to SDR use, there are incompatibility issues with the hard disk, optical drive, and existing graphics card, the hard drive has had an adaptor ordered for it to allow it to continue to work, the optical drive will be rectified later as it's not important at this time, the power supply should be sufficient for the new board, the only card that will be fitted is to be the CMI8738 sound card that the machine already has and that is compatible with the board.

Performance with SDR# has been dire with the RTL-SDR operating, the FRN client does work... just, the shackcam feed isn't really reliable on the machine (it's controlled by it both hardware and software, though I intend to replace this with a network camera,, which will make it software and link), and with plans to do the Amateur radio foundation exam as well I want the machine to reliably handle the Echolink software.  Another radio software installed on the machine is Zello, this runs reasonably OK but I tend not to use it as I use it on my phone more than I do on the computer.

Programming my Wouxun KG-UVD1P has proven unreliable with this machine, upgrading the internal hardware may be sufficient to remedy this (the official software, that is practically incomprehensible, works fine, the easier KG-UV commander doesn't read the radio properly, though it could be a bug with the software rather than the computer).

I should be taking delivery of the motherboard and it's ancillaries by Wednesday at the latest, for fitting that evening, which will take out the 446 gateway for a couple of hours but this is no real issue, the RAM on the existing board, if compatible, will be used in the 446 gateway computer to hopefully try and improve things, the GPU in that machine will also be swapped out with the one in the shack computer as I feel the one currently fitted to it is wasted in it and would be useful in another installation.

So, a better shack computer and maybe, just maybe, a President Grant 2 will be sitting on my shack desk soon, but we will see :)

73 de 26CT730