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GW/NW-043 - Cyrn-y-Brain


#1

Hi

I have chased this summit on several occasion over the past 12 months without any problems.

However, this past week Tom, M1EYP, and today, Nick, Pete & Dave (GW3TQQ, GW4OOE & MW0HQO) have all found it very difficult to hear stations calling them. Tom was unable to hear anyone at all!

All stations were 5&9 +30 with me in Crewe

It appear that the Comms tower on the summit is the cause of the problem and a switch of radio (to a Kenwood) helped the intrepid 3 today.

Beware of radios with a barn door front end!

Regards

Dave
(M6RUG).


#2

Alternative is just to walk a little further to Watkins Tower and you may find the sensitivity improves.

I think Tom was right next to the tower near the fence when he went up, a test for any front end conversion stage, Even the almighty kenwood radios woooood struggle…

The first tower is still active with several services http://www.sitefinder.ofcom.org.uk/search

Although the second seems somewhat under utilized currently !

Jonathan


#3

Hi Jonathan

The Kenwood did a mighty fine job and I got a 59 both ways :smile:
73

Dave
(M6RUG)


#4

Oh I know some of you are absolutely besotted with them :smile:

Jonathan


#5

Not me!

I have a TM-V71E 2/70 and it gets hammered by nearby paging systems so it is now on the shelf and I now use an ancient Trio TR-751E for chasing on 2m

My Kenwood TS-570DG(E) is in need of hearing aids so I only use it for TXing - I use and Eldad FDM-S2 for RXing with a Magloop.

Dave
(M6RUG)


#6

Very nice. Interesting radio with the ARM STM32F405 being implemented within it. The current consumption is very low for its architecture.

Jonathan


#7

Very impressed with it and it certainly blows the Kenwood away as far as RXing is concerned.

I would really like a wide band Welbrook loop for an RX only antenna so that I can take advantage of the 2 channels and 4 virtual receivers per channel to the full advantage of it :wink:

I can dream…

Dave
(M6RUG)


#8

An interesting diagnosis of the issue. Not the correct one though :wink:


#9

Educate me then :wink:

Dave
(M6RUG)


#10

I have successfully activated this summit on four previous occasions with various handheld radios without any problems. However, I had experienced similar problems on the Great Orme last year.

Today we drove 330 miles from North Yorkshire to the Ponderosa and back and we tried to keep to our alerted times as best we could. We were 18 minutes late on GW/NW-042, partly because we enjoyed a bacon butty and a drink at the Ponderosa before starting our walk. We worked ten stations on 145-fm. On our second summit for the day GW/NW-043 we were bang on time and worked five stations on 145-fm. We were aware of the microwave problem and did move back down towards the Ponderosa, keeping within the activation zone and we also tried using the antenna horizonally polarised as well as trying two different handhelds.

Karen 2E0XYL had made me aware about walking further along to the actual trig point (that is lower than the summit) to try and avoid this microwave problem on a previous activation. Dave, Pete and I had a discussion about this and we did consider moving to the trig point but I ruled it out because of the time factor. I knew I had a four hour drive back home and we also needed to stop somewhere for a meal as we hadn’t eaten since our bacon butty!

I am sorry if there were chasers out there that were disappointed. We do try and do what we set out to do in our alert as we did on this occasion. However, there are times when plans have to be changed, cancelled or are unable to be modified because of the activators’ needs.

Thanks to all the stations that we did work successfully.

73
Nick GW4OOE/P (with Dave GW3TQQ/P and Pete MW0HQO/P)


#11

Nick (Dave & Pete)

I was great to work you all on both summits, I think for the second time, and I look forward to working you ll again in the very near future.

As a foundation license holder - and not very technical - I would love to understand how that comms tower has suddenly started to cause problems and how activators can overcome whatever issue there is…

The switch to the kenwood certainly made a difference and I completed with all 3 of you. I dod not , however, complete with tom on 2m on his last visit.

I was aware that you moved away from the tower but I lost you completely!

Many thanks for the activation and hpe to work you again soon

73

Dave
(M6RUG)


#12

A new transmitter/antenna combo has been installed on the tower and the transmitter frequency will be “in the near” of 2m. The result is a high ERP signal close to the frequencies you want to use. Now whether this will be a big problem, a little problem or no problem depends on the receiver used at the summit. Many older radios had very effective filtering/RF stages such that they are not affected much by nearby strong signals. But the drive to produces radios that can tune from say 128-180MHz means that filtering is harder to achieve. And if you buy cheap there is less filtering. Also many handhelds are designed to work well with a rubber duck by having high RF gain. Put a better antenna on and you increase the chance of overload with in-band (2m) signals never mind the problem of overload from nearby signals.

There are many other effects that a signal overload can cause. But the effect is often mitigated by moving away from the offending transmit antennas. Maybe just a few hundred meters further along the summit ridge can reduce the overload to a point that the receiver now works acceptably.

The fix is to use a receiver that works in such poor locations. From experience most of the old radios will be less affected, FT-290, TR-2200, TR-2300, IC-240, IC-22 etc. Some modern handhelds are good, VX-170, FT-250 are 2 that are better than many others. ISTR the FT8x7 2m receiver is OK as well. Or you can have a filter in the antenna that is a 2m bandpass. But this is anything but trivial to make. In order for it to be effective it needs very steep skirts so that the inband loss is a db or so at 145MHz but the attenuation is 60db+ at 153MHz, a frequency used by many paging transmitters.


#13

Yes, I have had no trouble with the FT817.

Brian


#14

It sounds as if my activations of this hill with a VX-7 (described by some as ‘as open as a barn-door’ to interference) will be even more challenging but, with that radio, there is an easy alternative: operate on 70cm! I agree that this is more likely to be successful if a) you have alerted this frequency or can self-spot or b) you have already worked Moel y Gamelin on 2m (no problems there) and also 70 cm and announced your intention to use 70 cm on the second hill. Alternatively, as suggested, use a 4 pole helical filter (handcrafted by M0JLA!) which certainly worked well with the old set up but I haven’t been there since March 2015.

Another tip - time your visit very carefully, especially in appalling conditions. I staggered up there (it was my second summit and the Ponderosa wasn’t even open when I passed it first time) in March in a windy and bleak conditions with rain starting. Being passed by a tractor and a small van (which parked by the mast) on the way up did not improve my mood! Hunkered down behind the sheepfold and started 70 cm with an instant response from M6RUG (thanks Dave) followed by 6 more on 70 cm (I wasn’t getting the filter out in those conditions) and I was packing up within 15 mins. I was disappointed to see the van had gone (ever hopeful!) and started the trudge down the track into the wind and rain and suddenly saw a van stopped on the track. I started to run and wave… and got a dry and warm lift down the track by the mast repair man who had stopped to take a photo(??). He visited, on average, once a year, and was very happy to drop me in the Ponderosa car park so I was walking into the cafe as M0JLA contacted me from just outside the other door to find out where I’d got to. My suggestion that he looked round was obviously not expected! (The Ponderosa tea and something hot was very, very welcome.)

So this was my lucky moment on a SOTA summit - but I better others can come up with better
tales! Being choppered down to their car - without a broken leg or damage limb??

Viki M6BWA


#15

I thought that that is what my “diagnosis” was in the first place - or did I use the wrong words Tom???

What you describe is exactly what I have in Crewe as I am in close proximity to the only 2 tall buildings and they are bristling with antennas. My Kenwood TM-V71E has a very wide receive and I get hammered. While I use a notch filter to filter out 3 paging systems I am still getting hit by many other systems.

Switching to the old TR-751E has solved the problem completely as it is pure a 2m all mode rig !

Dave


#16

Hi Viki

Long time no QSO ;(

Unfortunately my 70cm rig is now on a shelf which is a shame as we have had some quite remarkable QSOs on 70cm - including at least one in South Wales - which is some considerable distance from here!

I have seen you out on several occasions but not managed to work you this year.

Hope to chase you soon :wink:

Dave
(M6RUG)


#17

Hi Nick, thanks for the contact yesterday from your first summit, I heard you on the second one up to the point that you moved & after that I lost you completely.

During your activation of the first summit your signal was very up & down as you passed the mike between the three of you, Dave was the weakest followed by Pete, your signal was the strongest, I thought perhaps your problem must have been antenna related given the WX conditions you were describing.

I worked Pete & Dave from Shinning Tor back in December & their signal was also up & down at that time, Im not sure if that was using the same equipment as you were yesterday.

Thanks to all three of you for the chaser points & well done for braving the blizzard conditions, look forward to another contact at some point in the future.

73
Neil


#18

Hi Dave,

Your diagnosis referred to rigs with a “barn door front end”.

I wasn’t using one of those.

Jonathan’s diagnosis would seem nearer to the mark. I must try 2m FM from my usual spot beside the stone shelter next time, and see how that compares with previous years (when there has been no problem).


#19

It seems it was 2010 when I was last up there. I must visit again sometime.

I used the stone shelter near the Band II FM broadcast mast (the first one you pass as you climb the road) and I can recall there was something there then that was producing clicking on my radio and some desense. I’m not sure if I was using my VX-170 or IC-80AD but there was enough desense for some callers at 51-52 reports to disappear when whatever was TXing. So it wasn’t terrible but was noticeable. That was 5 years ago. I remember at the time that was unusual as that summit used to be my favourite contest perch and it was clean on 2m during all of the 1990s. The only issue was our 70cms preamp had problems with a harmonic of the Radio 3 FM signal and we had a simple 1/4wave coax stub on the preamp input to fix that.


#20

Thanks Tom

Just checked my stats; chased it 12 time this past 12 months on 2m, 1 total failure (M1EYP/P) 11 successes.

Of the 11 successes, only this last one was difficult but got there in the end :smile:

Dave
(M6RUG)