First participation in the Sunday net on GB3IR

Last night was my first participation in the Sunday night net on GB3IR, most if not all the regulars were on, along with myself and 2 of the other newly qualified operators, and this revealed a problem I was having which I shall outline later.

I was happy to take part in the net as I'd been itching to since I passed my exam, this means I now have something to occupy an hour or two on a Sunday night if nothing else already has, and if I am in the car it's no problem because I have a rig in the car as well as my two handies, out of range of GB3IR I just have to connect over Echolink through my computer, phone, tablet or another Echolink enabled repeater so I have no excuse to miss out.

Now, the problem, I own a speaker mic, which I have had for some years, turns out it's so cheaply made that the audio from it is absolutely dire, I even tested it between the handhelds on a clear frequency to find out, so it means I am going to have to do of two things, new speaker mic or just use the handhelds without, both handhelds, even the Wouxun with the longer antenna at 1 watt,were operating perfectly fine, so the best thing I can do is ditch the speaker mic.

So next Sunday I will be on at the same time, unless something else takes priority of course.


73 de M6RSQ

Equipment for PMR446 antenna upgrade ordered and a few other bits

I have placed an order for an SWR meter suitable for the PMR446 channels, I have also added tp this order some PL259s suitable for some cable I found I had lying about which is suitable for use on UHF but not as heavy as RG213, an SO239 coupler identical to what is fitted to the T2LT so the antenna and feeder can be connected together (I will be sealing this up with black sugru to protect it from the elements) and a SMA-F to BNC adaptor to fit the Wouxun in order to attach my Nagoya NA-771 to it when it becomes free again (once the Intek is on the bazooka and operating happily into it)

The SWR meter I have ordered covers from 140MHz (meaning I can use it on 2-meters to double check the slim-Jim on a radio and in situ once I have a license), all the way up to 525MHz (so PMR446 is included), my good CB SWR meter is valid up to 200MHz so for 2-meter antennas I can compare the readings.

The bazooka will be checked for SWR in two places, the first being at Whaston Road car park, my favourite DX spot close to home, the SWR will then be rechecked when the antenna is up in the air, I still need to add some rigidity to the driven element to keep it as vertical as possible (PMR446 units all have antennas that are near enough vertical as almost all type approved PMR446 radios are handheld units (the exceptions to this being the Intek DRS-5070 and it's cosmetically identical predecessor, the Midland BaseCamp446, and the Alan Base446, but these all can operate on batteries and are still portable rather than fixed like a base CB or home Amateur station, the BaseCamp446 has a mic holder on it's rear panel).

I expect to take delivery of the items I have ordered in the middle of next week, and I expect the PMR446 gateway to be moved off the Nagoya and onto the bazooka by the end of next week, range tests will then be carried out once the antenna is up, including to Northallerton, I look forward to seeing if at last I can make it there on PMR446, it's a big ask but it's worth trying.

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

RTL-SDR enclosure prepped

I picked up 2 different diameter hole saws today to enable me to cut the hole needed in the lid of the tin for the USB connector for the SDR, the connector was fitted after a suitable hole cut and another hole drilled through for a screw (a second screw will be sourced and used later to finish the job).

A connecting lead for the antenna socket on the stick was sourced from the magnetic mount stick antenna that was supplied with the RTL-SDR stick, it was simply a small amount cut from the lead with the MCX connector intact, the cut off end was simply prepped and soldered to the appropriate points on the BNC connector, with the excess trimmed off, continuity was checked before the lead was connected to the stick.

The stick was then tested with just the antenna socket, I installed the SDR# software to do this, it worked as it should have done, the stick was then connected to the USB socket inside the tin lid and the tin closed up, it still works, the NA-771 antenna is not tuned for everything the RTL-SDR is capable of tuning to, but it seemed to work OK in the broadcast band, it of course worked fine in the 2-meter band and on PMR446 (PMR446 frequencies fall into the 70cm band in the US so to be expected). I tried it on 11-meters including on 27.555 MHz, but no luck, partly due to being indoors and partly due to being the wrong antenna for the band, a final test was to see if broadcast reception was eliminated while inside the tin, it was.

The last stage of this project is to fasten the USB connector down properly with one final screw, silicone seal the inside of the tin to be sure that no leaks can occur, fill it with oil after the silicone sealant has cured, and immerse the operating RTL-SDR into it, the reason I want it operating while I do this is to ensure that the stick continues to work while immersed in oil, SDR for mariners claims that it does.

It has taken me a bit of time but I finally have got the tin fitted out.


73 de 26CT730

Binatone Action 950 modifications

Note, For information only, I do not recommend or encourage modifying PMR446 radios, you do so at your own risk

One of my own Binatone Action 950s has been put forward as the radio, the other one of the pair will remain unmodified

This is the radio in question, this radio will be modified to include a BNC socket and antenna, a power mod does exist but requires some SMD components as well as a switch or two solder pads bridging, the bridge has been made but the components are not present so the radio is still at 500mW

This is the same radio as above but with the antenna removed ready for a BNC socket to be fitted

This is the radio with it’s BNC socket installed, the bottom part of the antenna has been used to accommodate the BNC socket, the BNC socket cannot be soldered directly to the board, a small piece of wire had to be soldered between the centre pin of the BNC socket and the antenna connection on the board, the ground is soldered to a nearby solder pad that connects to ground, for stability the area around the socket will be filled with some epoxy, this should stop it moving about as although the BNC socket is a tight fit, it does move a little so this is recommended

This is the antenna I intend to fit to the radio, Nagoya NA-771, this antenna is a dual band antenna for the 2 metre and 70cm Amateur radio bands, and as the latter includes the allocation for PMR446 in the US (where PMR446 is not used) this antenna proves somewhat suitable

And here is the final result, the radio now has the new antenna fitted, and seems to work fine and has survived it’s operation
Now to see how good it really is
73