Originally posted by Jarod
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Originally posted by DemonLee View PostAre you sure that is correct, I use an FR24 Antenna with their receiver and in some directions easily break the 300nmi distance...! I appreciate that I am 176m [AMSL] but compared to the Cantenna's and Colinears I have made and tested, they don't get anywhere near those kind of distances.
It seems my GP is the perfect length on the vertical and radial. This is 100% luck, as i just cut it on about 6.54 cm if i can recall next to the measure lint.
Next antenna to test will be:
http://shop.jetvision.de/epages/6480...oducts%2F68200 "Active Diapason" Antenna (1090 MHz)
Will keep ya all posted.
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Originally posted by Jarod View PostWith these cheap and handmade antennas you need a bit of luck too.
It seems my GP is the perfect length on the vertical and radial. This is 100% luck, as i just cut it on about 6.54 cm if i can recall next to the measure lint.
The reason the collinears are hard to get right is that these are highly intolerent to dimmensional errors cased by poor design and/or poor construction. A few mm error can push these antenna from "excellent" to "poor" category. These need test equipment to trim & tune to get them work properly, but most DIY antenna makers lack these instruments.
On the other hand a 1/4 wavelength GP (groundplane) antenna is not only naturally tuned, but has a high dimensional tolerance, and is not knocked out by few mm error in dimensions. It therefore works good even without tuning with the help of test equipment.
Here is a tip for GP antenna makers: enlarge the horizontal part of groundplane to dia = 1/4 wavelength
The GP antenna is usually built using a N-connector or SO239-connector. The 1 inch x 1 inch (25 mm x 25 mm) flange of these connectors is part of the groundplane of the antenna. If this horizontal part of groundplane is enlarged to have a dia nearly equal to 1/4 wavelength, while keeping the radials 1/4 wavelength from the outer edge of horizontal part, the performance of GP improves.
I have experienced this magical effect when I tried Canrennas with can diameters 20mm, 54mm, 68mm & 100mm. The best result was obtained whith the can dia 68mm i.e. the dia of bottom of can was 68mm, almost 1/4 wavelength.
Some other users have tried horizontal flange enlarged to 2.5 inches (63 mm, nearly 1/4 wavelength), and have reported enhanced performance. Photo of these GP are given below.
Cantenna with different can dia / bottom dia
Example of 2 GPs with groundplane enlarged to 2.5 inch dia (nearly 1/4 wavelength).
TomW's GP with 2.5 inch / 63 mm dia disc. Click here
blueskyspotter's GP - Click here
F1Rocket's/gnuse's GP - Click here
Last edited by abcd567; 2016-02-11, 03:50.
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Originally posted by Jarod View PostWith these cheap and handmade antennas you need a bit of luck too.
It seems my GP is the perfect length on the vertical and radial. This is 100% luck, as i just cut it on about 6.54 cm if i can recall next to the measure lint.
Next antenna to test will be:
http://shop.jetvision.de/epages/6480...oducts%2F68200 "Active Diapason" Antenna (1090 MHz)
Will keep ya all posted.
But when you are at a location which is high and has a good 360 degrees view, the upgrade from the standard FR24 antenna is not worth it.
Please note: Tested in The Netherlands, Amsterdam.
The Netherlands is a very low country and a lot of it is below sea level. This severely limits my range.
But still being in the top 70 isn't that bad. But it can't be improved by a better antenna. I guess i need to find another 100m upwards.
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I must admit I'm new to this, and I have just started feeding (T-YHBA5) but I'm in the process of getting my setup sorted.
I have it mounted on my tv antenna mast, using a 1m aluminum pole extension to ensure it's higher than the tv stuff and has a clear view.
But my issue is -
When first testing, I used a 10m cable from the antenna and had it mounted just on top of tv antenna pole (no extention), my range was good, and possibly 50nm more than now.
Since I added 5 m more of LL cable and raised the antenna 1m above where it was, my range has dropped. Could it be because of the aluminum mast - should I have used galv. steel ? 5m more cable ?
I have another option, where I can mount the antenna lower, on the roof of the verandah/patio, it will have a clear view of the sky, just 3m lower overall and not above the roofline.
Will probably be trial and error but without drilling too many holes in my roof any suggestions?
**Ive attached a photo showing the antenna on the 1m extension and you can also see the previous height of the tv mast.
Thanks in advance - I'm only learning IMG_0491.jpgT-YHBA5
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Thanks Oblivian, back to a 10m cable, and antenna 1m lower than before - compromise but coverage up to 124nm from about 60-70nm with the 5m of extra coax i had before.
Originally posted by Oblivian View PostCable Distance + new connectors = more loss before receiver
Sent from my XT1092 using TapatalkT-YHBA5
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Originally posted by Oblivian View PostCable Distance + new connectors = more loss before receiverOriginally posted by jpsimmo View PostThanks Oblivian, back to a 10m cable, and antenna 1m lower than before - compromise but coverage up to 124nm from about 60-70nm with the 5m of extra coax i had before.
Last edited by abcd567; 2016-05-22, 06:27.
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Originally posted by abcd567 View PostWhy not add a Satellite amplifier. You will then be able to add extra cable to raise your antenna. The Satellite amplifier has a gain around 15 to 20 dB, whereas loss in your extra coax & connectors will not be more than 3 dB. The amplifier will not only cover for losses in cable & connectors, but will also boost the signal. Your range will increase substantially.
Thanks in advanceT-YHBA5
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This is what I use (RCA D903, 950 Mhz - 2050 Mhz, 13 - 18 dB) purchased from local store for $4.
However it is not necessary that you use this model. There are a very large number of equally good satellite amplifiers available on ebay. Search ebay for "satellite amplifier" and you will get a big list.
RCA D903.jpgLast edited by abcd567; 2016-05-22, 06:47.
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Originally posted by abcd567 View PostThis is what I use (RCA D903, 950 Mhz - 2050 Mhz, 13 - 18 dB) purchased from local store for $4.
However it is not necessary that you use this model. There are a very large number of equally good satellite amplifiers available on ebay. Search ebay for "satellite amplifier" and you will get a big list.
[ATTACH=CONFIG]7528[/ATTACH]T-YHBA5
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