40miles 10w FM – Llancloudy to Cheddar (GB3WR)

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Recently I spent the weekend at Merediths Farm and Campsite in Llancloudy, a lovely quiet campsite. I set up a 2m 3-element beam (arrow) at 5m on top of a painters pole and pointed it due south. It was a test run to see if I could operate through GB3WR, over 40 miles away due south.

The height profile implies that it should not be possible. GB3WR is the yellow blob in the map above, my location the blue blob in Llancloudy. Amazingly I could open up the repeater with just 10w from the IC-705, so I put a couple of calls through it and made some contacts !!

G1WOV was the first, but I had attenuated WR too much when direction finding and missed his replies unfortunately. I then had contacts with M0HWP Jeremy, and M7AJO/M Callum. Dale, 2W0ODS then called in and we had a good chat, Llancloudy, through GW3WR, and into Barry, great stuff.

The repeater was about S5 on the IC-705 meter, I was running 10w into the 3 ele beam.

Cheers for the contacts which made it resounding success.

73

Meshtastic – A healthy mesh

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There has been a significant rise in the quantity of nodes in our local vicinity, leading to a notable surge in activity on the 869.525MHz single channel. Some nodes are indicating LongFast channel usage rates of 30-50% even during off-peak hours, which is deemed excessive. Research conducted by BRS3 (Mopatops Bristol) has revealed that numerous nodes in the region are excessively transmitting on the channel, akin to ‘spamming’. Thanks to BRS3 for the information regarding these settings. The following is a 24hr snapshot (14/04/24) of direct data that BRS3 received.

It has been observed that sending a text message can often be challenging due to the channel being congested, even when attempting to reach nodes in close proximity. Therefore, it would be advisable to consider restricting the automatic transmission of packets to the mesh in order to alleviate this congestion. The settings outlined below have the greatest influence on the default automated packet transmissions sent to the mesh.

  • Node Info – 10800 seconds (10800 is the default)
  • Position – 3600 seconds (changed from 900)
  • Telemetry – 7200 seconds for all (changed from 900, ‘device metrics’ always gets sent at this interval. It sends battery state and the like to the mesh)
  • Neighbour Info – disabled (disabled by default, leave unless you have a good reason, and know the reason for using it)

I’ve configured the following settings for my nodes in an attempt to reduce the automated transmission of unnecessary data to the mesh. The values highlighted in orange are the crucial ones; please disregard the others as they may not align with your requirements.

Happy Meshing !

Device Config (Node Info)

Position Config

Telemetry Config

One callsign to rule them all

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With the new/recent Ofcom amateur radio licence changes, we are permitted to hold only one personal callsign. To that end I have released my Foundation MW6LGA callsign, and my Intermediate 2W0LGE callsign.

Portable Beam

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So I picked up one of the ARROW II 146/437-10BP portable 2m/70cm beams for some satellite and portable/mobile activity. Three elements on 2m, seven on 70cm.

I decided that I also wanted it on top of a 5m painters pole for easy setup when I am out in the van so I picked up an adaptor from Amazon. It was a bit pricey but it did the job and seems very strong.

I cut up some box section cable trunking I had and mounted to the top of the adaptor with a few screws and washers. I pre-drilled the adaptor plastic.

A small cut out to take the curved section on the adaptor can be seen below. It lets the box section sit flat.

I put together some velcro straps and screwed them into the adaptor with washers. The foam/sponge grip of the antenna sits snugly in the box section and can then be velcroed in place.

A quick test setup on the van on the top of a 5m painters pole. I am looking forward to using it when next out and about.

73 !

MB7TR – SSTV Repeater in Magor

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UPDATE: MB7TR is now also closed down. There was not enough activity in the area to make it worth while.

Peter (MW0RPB) closed down the MB7TR 2m repeater in Cwmbran a year or so ago. I decided to start my own here in Magor. This time however, it would be on 70cm, using the same callsign.

MB7TR is now a 70cm, FM, regenerative sstv repeater based in Magor, S.Wales. It shares the Diamond X300n antenna with APRS station MB7UNE.

All details can be found HERE.

ToyoCom TCO-613 5MHz frequency test

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A friend and fellow amateur radio enthusiast, Ross GW3NWS, let me borrow one of his TCO’s, a ToyoCom 5MHz unit.

Pin-outs of the ToyoCom TCO-613

As I wanted to obtain some higher accuracy to the results, I decided to use the 9th harmonic at 45MHz. The signal was observed on a SunSDR2 Pro, that had been provided with a GPSDO 10Mhz reference signal.

The TCO-613 was powered up from cold, the following was observed, again using WSJT-X in FreqCal mode. After 12 minutes the TCO settled to around 0.43Hz high at 45MHz, an average of the last 8 minutes of delta frequency. The test was concluded after 20 minutes. No adjustment had been made and was tested as provided by Ross.

ICOM IC-705 Frequency Stability 1

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Since I recently modified my IC-9700 with a Leo Bodenar master reference insertion board providing it with a GPSDO locked master frequency of 49.152MHz I have been looking at drift of a number of my radios. I decided to test the IC-705.

COOL DOWN

I set the IC-9700 to transmit a carrier on 439.999MHz into a dummy load @ 0% RF (perhaps 1-2W not tested). This transmission was performed for 2hrs and monitored on the IC-705. I dropped the RX gain on the IC-705 and offset the VFO -1.5kHz so that I could monitor it using WSJT-X in FreqCal mode. The audio was taken from the IC-705 and provided to WSJT-X. The carrier would now show at 1500Hz in the audio passband in WSJT-X. The FreqCal mode shows delta frequency from this 1500Hz middle point.

I do not have any temperature values, however the in built temperature display was observed at the start and end of the test. The orange bar shows the swing, from high (right side) to low (left side).

FM deviation using Bessel Zero method

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I decided to try to work out the peak deviations in FM when transmitting from an IC-9700 and an IC-705 into a dummy load. The receiving transceiver is a SunSDR2 Pro without antenna connected. I used a software sig gen to feed both Icom radios with an audio tone via their USB audio interface.

This tone is adjusted whilst observing the FM transmission on another SDR receiver, or listening to the fundamental frequency with narrow CW filter. The injected tone’s frequency is adjusted to bring the main carrier frequency to the zero point (null) in the bessel function, the carrier at the fundamental will drop to zero on the sdr, and it will go silent on the receiver that is listening in CW mode.

Bessel Function

  • 1st fundamental crossing = 2.4048 modulation index
  • Deviation = 2.4048 * AF (where AF is the audio frequency applied that results in a null carrier at fundamental RF frequency)
  • Bandwidth = 2 * (max audio freq + peak deviation)
  • Assume 3k peak audio frequency for voice used in bandwidth calculations

IC-9700

1830 Hz FIL1 = ±4.4 kHz dev
913 Hz FIL2 = ±2.195 kHz dev

FIL1 BW : 14.8kHz
FIL2 BW : 10.39kHz

IC-705

1762 Hz FIL1 = ±4.24 kHz dev
889 Hz FIL2 = ±2.13 kHz dev

FIL1 BW : 14.48kHz
FIL2 BW: 10.26kHz

FM from IC-705 with 1762 Hz tone applied
NFM from IC-705 with 889 Hz tone applied

Icom Remote Utility Issue and Hamlib

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When running JTDX (version rc155 with the ic-705 supported) and the Icom Remote Utility I kept getting annoying errors from HamLib which made it unusable.

Hamlib error: Protocol error while getting current VFO frequency
Hamlib error: Command rejected by the rig while getting current mode

It seems that if you turn OFF the CI-V Transceive option in the Connectors->CI-V menu this fixes the issue. All problems went away, however I did need to restart the Icom Remote Utility.

I assume Hamlib wasn’t handling the returned ci-v commands with the ci-v transceive setting enabled. This may be the case on all Icom radios, not sure, however it is a default setting on the ic-705.

73 Richie.