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Found on G/WB-002 antenna part?

Hi,

Today on the way up Brown Clee hill, I found a length of aluminium rod which could be part of an antenna. It is approx 41cm long, and is marked close to one end with blue tape.
Of course it may not be antenna or SOTA related, but is it yours…?

I see from the database that Phil @G4HQB and Gillian @M0OVW activated there recently, but it could have been lying at the side of the path for some time.
(Late last year @M1EYP, @M0VFC and @M1HAX)

Photo below, I have it if anyone wants to claim it before it gets re-purposed!

73
Adrian

(PS 34 stations worked on 2m FM from Brown Clee today, and 3 on 70cm. Many thanks for the contacts)

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Hmm, I don’t recognise it! Thanks anyway Adrian :+1:

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Hi Adrian

Thanks for the QSO today - 34 is a great score, there seemed to be lots more chasers around today than yesterday. Out of interest, what rig were you running, and how did you manage with the intermod from the towers ?

Cheers

Rick

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Hi Rick,

Thanks for the QSOs, the level of activity was a pleasant surprise for me too, it kept me busy for most of an hour. I’m sure that I missed some callers - sorry. One of the features of FM is that the receiver captures the strongest signal each time you call QRZ? and others just don’t get heard. With SSB or CW (AM) there is the possibility of hearing a weaker signal calling each time and inviting them in in turn.

I was using an FT817 with a wire Jpole made from 450 ohm twin feeder on a 7m pole. I set up about 100m south of the trig point, so maybe 200m from the main tower.
I didn’t hear any interference, and don’t think I suffered from any de-sensitising - I’ve never experienced a problem with the 817 near commercial radio masts.

Interestingly, I had my FT70D hand-held switched on on the walk up, and while I was setting up at the top, I heard a couple of stations calling each other on 145.500 without any interference. I didn’t investigate its use any further, the chilly wind didn’t encourage me to spend more time playing - but either the FT70D is more resilient than others that I have tried up there, or else the commercial services have changed / were not operating at the time.

A different story on Titterstone Clee a bit later, wet low cloud and a stiff wind had me soaked before I reached the top - I worked all callers until a few more CQs went un-answered, and then headed back to the car for coffee and mince pies :smiley:
Cheers,
Adrian

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817’s are known for their bulletproof frontends on 2m. Tom M1EYP has said his FT70 seems to be very good in high RF environments and your brief use of your FT70 would support that.

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Indeed my recent activation of G/WB-002 was using just my FT70D with rubber duck.

Therefore:

  1. I can confirm this rig copes very well in RF-polluted environments like this.

  2. That metal rod is not mine.

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No, yours would be bent in 3 dimensions by now :slight_smile:

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Hi Adrian,
Thanks for picking up the rod, Yes it belongs to Philip and I. We noticed it had broken when we got home.
Where about was it?
It has snapped, so is now too short, but we have spare bits of metal to make a new one.
Good to talk to you today on both your summits.
Gillian

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Hi Gillian,
It was on the path up, somewhere near where it changes into open country from being a narrow steep sided track…
Yes, thank you for both contacts, good to get you in the log.
73
Adrian

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This is what happens when you use your kit :wink:

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Thanks for the chaser points Adrian, working from home yesterday as Jonty (aged 10) tested positive on LFT and pcr on Saturday - consequence of kids back at school ! But at least I could play SOTA at the same time as working. You were much weaker signal from Titterstone than Brown Clee - did you suss out what was causing the high SWR.

73’s Steve.

Hi Steve, thanks for the contact, and best wishes to you and your family for a speedy recovery.

The SWR is OK when the antenna is dry, but changes drastically in the wet - much more than I remember from past activations. I’m letting it dry thoroughly, and then I will investigate - I’ll post again if I discover anything interesting!
(The antenna in question is a wire Jpole made from 450 ohm ladder line, with 7m of RG58 coax attached, and is usually supported by a 5m fibreglass fishing pole. I have a choice of poles, so it could even be that this one becomes more conductive when wet, and upsets the antenna…)

73
Adrian

I think the rubberduck also helps keep the overall RF level into the frontend down
VHF takeoff from this summit is excellent by the way

Cheers
Rick

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Hi Adrian
Do you have a common mode choke on the Jpole? On my SlimJim I have a number of clip on ferrites on the coax and I haven’t noticed any issues. My rig doesn’t have a SWR meter and I try to avoid the rain so maybe that doesn’t prove much!
73 Richard

Indeed Rick. This is just one of the many advantages that a rubber duck has over any replacement antenna.

I’ll always use proper better portable antennas when activating with the FT-817, but if doing a planned, intended handheld activation, the rubber duck is unbeatable - overall*.

*But not in every aspect, obviously!

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Using the rubberduck also avoids trapping the antenna in the car door like I did with my RH770 on Sunday :frowning_face:
It’s got a big kink in it now, need to order a new one methinks !

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But you risk sitting on the ht and breaking the rubber duck as you get in the car because it was in your back pocket :slightly_frowning_face:

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Off topic, but continuing this line of thought…
I set up the wire Jpole in the garden this afternoon, and my MFJ analyser suggested that the SWR at 145.5 was 1.4:1.
I then sprayed the matching section of 450 Ohm ladder line with water, and the SWR then read 2.2:1.
Substituting the FT817 for the analyser, the SWR display was showing 4 bars on the bar graph - as it was recently on a wet summit. This looks quite dramatic, but if it represents 2.2:1, I can live with that!
These measurements were taken at the end of 7m of RG58 feeder (and so they are unlikely to be an accurate representation of the impedance at the antenna feed point), but since this coax is permanently attached, they are good enough for all practical purposes.
I might consider cutting a few holes in the lands of the ladder line, or applying some silicone wax to make the water “bead up”, but that’s for another day.
To complete the experiment, I wiped the matching section dry, and noted that the SWR had returned to normal.

Hi Richard - yes, a few turns of coax on a length of plastic pipe, close to the feed point.

73
Adrian

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