Other SOTA sites: SOTAwatch | SOTA Home | Database | Video | Photos | Shop | Mapping | FAQs | Facebook | Contact SOTA

Antenna


#1

Hi everybody
I searched on the reflector for “antenna”. The result was poor. What kind of antennas do you use for your sota-activities? I use a groundplane (10m fiberglas telescope pole) with two radials and an elecraft T1-tuner. What’s your experiences?

73 David, HB9RVS


#2

I also use a linked dipole similar to John GW4BVE as do a fair number of activators. I have been using one with two sets of links for 60/40/20m but have just built one for 10/20/40/60/80m but it has not been used on a summit yet.
I also have plans to add 17/15/12/6m in the form of a removable linked fan rather than add more links to the existing antenna.

73 Steve GW7AAV


#3

In reply to 2E0HJD:

Hi Mike, tnx for the link. The wight (without the telescope pole) of my current antenna is only 100gr. The wight of a (40m resonat)Dipole is higher. The more of weight should result in better prformance! I think I have to test both antennas.

73 David


#4

In reply to HB9RVS:

Hello David,
I am also using a 1/4 wave vertical with usually 4 radials on a 10 m fibreglass pole. ( 40 m operation) often i do not use a tuner. On my tests I found this antenna nearly as good as an inverted vee, but I find this vertical much easier and quicker to erect on our steep and narrow mountains…

cu, 73
kurt HB9AFI


#5

In reply to HB9AFI:

Hi Kurt
Thank you for your information. The vertical is not so wrong… well I think I have to test both antennas. An other solution is the end feeded Fuchskreis. I never worked with this antenna. Several months ago I bought a kit. The kit is till now not assembeld…

73 David, HB9RVS


#6

In reply to GW7AAV:

Steve/John

How long does it take you to change bands and do you need to drop the antenna each time?

73 Glyn


#7

In reply to GM4CFS:

Hi Glyn - I`m the wrong Steve, but my antenna is the same. It takes me between 1 & 2 mins to change the links - obviously it will take longer to do the 60m links as opposed to the 10m links. I only need drop the fishing pole one segment to change 20m links & 2 segments to change 10m links, the 40m & 60m can be reached from the ground.
73 Steve G1INK.


#8

In reply to G1INK:

Thanks ‘the other’ Steve might give that a bash. Currently using CWI’s inverted V long wire with the T-1 tuner.

73 Glyn


#9

In reply to GM4CFS:

Ditto: What Steve INKy said with regards to the time to change bands at the maximum, if that was all I was doing. I tend use it as an excuse for a stretch and to go and see how Helen is doing on 2m while I am up and about so that sometimes delays me or sometimes I can get the kids to break the links so it only takes seconds. The terrain comes into play too, wading through thick heather or picking you way around brambles. Fast changing of bands is over rated on summits because if the chasers are on old manual tuners (like me) it takes a while to get to the new frequency and by the time we are set-up you have got bored or gone hoarse and I know there are a few EU chasers and some M3s who listen on 5mHz so they know when the station is going to 7mHz where they may be able to work them. Very handy to have a fast band change if you get the warning of an S2S on another band though.

Steve GW7AAV


#10

In reply to HB9RVS:
High David,

You may take advantage of my experience with antennas and gear used in SOTA activations:

• Wire 8,6m + 10m radial ….KX1(3W) + int. tuner
Remark: Vertical arrangement on fishing pole failed due to electric shock when pole was extended to lift the vertical wire to about 4m height and touching the lower end of antenna wire due to high static prior to snowfall out of blue sky. Wire was then used about 1,5m above ground in horizontal arrangement supported from the summits metal cross.

• Telescope-ski-stick with 40m loading coil and telescopic whip for tuning + 6,6m coax as folded radial …. ATS3 (2W)

• Fuchsantenna, 20m wire with Fuchs-tuner assembled from qrp-project kit with resistive swr indicator added. I used it on 20,30 and 40m……ATS3 (2W)

• Telescope-ski-stick with 40m loading coil and telescopic whip for tuning + 2 x 2,7m radials (tape-measure) ….KX1(3W) + int. tuner
Remark: trx exposed and damaged from static discharge. There was a nearby thunderstorm.

• Doublet 2 x 7,5m with symm feeder appr. 6,5m and Z-match (BLT-tuner) … Moskita (2W) 40m. Trx coax braid bonded to ground-spike as thunderstorm-like clouds approached.

• Linked dipole tuned for 20,30 and 40m.

Recommendation:
Antenna configurations with possibility for solid (DC) connection to ground or at least with static discharge bleeding resistor are preferred compared to configurations where the possible path to ground from the antenna will be the trx front end circuit only.
The L-network tuners like the internal KX1 tuner or the switched longwire tuner (qrpkits) do not provide DC-grounding for the centre conductor connected to the antenna.
Antenna matching devices like the Fuchskreis (available from qrp-project) or Z-match like BLT-tuner (available from qrp-kits), provide at least a separation between antenna and trx.
The link coil connected to the trx provides a DC-short between centre and ground of the trx input/output. Connecting the trx coax-braid to a ground-spike will help to bleed static discharge to earth.

Further experiments:
I hope to gain more experience with endfed dipoles using shorted lambda/4 parallel line for matching and grounding (as described for kite lifted antennas) or shortened dipoles with hairpin-match or doublets associated with Z-match-output coil providing a possible centre earth connection to protect the receiver front end and transmitter output.

72 Hermann, OE1HFC


#11

In reply to GW7AAV:

Thanks Steve (AAV) for comments. I will build the BVE ant and see a. how well it performs, b. how easy it is to make band changes and c. how the weight of that ant compares to the LW and T-1.

73 Glyn


#12

In reply to OE1HFC:
Hi Hermann
tnx for the infos. I had only once a problem with dc-discharge. For me was clear: stop the activity. How was the performance with the ski-stick as antenna carrier? The distance to ground is very small.
Has anybody experience with buddipole or budstick?
For the activity tomorrow I’ll have no telescope pole (it’s not possible to take with me…) . I hope there will be some possibilities to hang up the antenna wire.

73 David, HB9RVS


#13

In reply to HB9RVS:
Hallo David,
Telescope ski stick antenna with loading coil:
Top section with handle replaced with loading coil from old mobile antenna. Wire spiral inserted to compensate for different thread dimensions. (The lower two sections of the ski stick can be shorted or can be used as tuning capacitor of about 65pf to 1300 pf depending on the length extended - aluminium pipe ski stick with insulated locking mechanism.)
Wire attached to lower end of pipe carrying the loading coil and connected to centre conductor of antenna-connector of SWR indicator. Radial either 6,6m coax shorted on the far end with some wire for tuning or 2 x 2,7m metal tape measure connected to ground of trx. Tuning with telescope whip on top of loading coil. The top section with handle and second ski-stick together with bungy rubber band can form a tripod with the antenna. Performance is of coarse lower than Fuchsantenna or others but good for SOATA in restricted areas or at high wind speeds. In fact I replaced the heavy lower rod-section and base of the mobile antenna with the ski-stick. I used it on OE-ST-127 and 138.

gl es 72 Hermann, OE1HFC


#14

In reply to OE1HFC:
Hi Hermann
Do you have images of this setup?
As I mentioned I was yesterday before without telescope pole on HB/FR-027 and 030.


The antenna was not 100% perfect but it worked.

73 David, HB9RVS


#15

In reply to HB9RVS:

Hi David,

Unfortunately I have no images of the set up as I do not have a digital camera. I will try to get someone to take a picture on the next occasion to make it available.

73 Hermann, OE1HFC