KROSS model GY-TVA 003 (4 Bay whisker antenna)

[ota_canuck]

Well,.. in a simple scale up theory If you increased the UHF wisker lengths and adjust wisker spacing by 30%,.. you would have something that works within the 14-51 spectrum

That VHF dipole is probably already dimensioned correctly for VHF-hi

It is a nifty design though!

[mrpeter105]

I bought one of these a few months ago and have it setup in the attic. Before the transition I thought my attic mounted SBGH gen1 would be able to get rf11. Of course that didn't happen so I used one of these to see if I could get rf11, which it does a pretty good job of off the side. For my location CHCH on rf11 has a NM of 33 and the station is 45 miles distant at 197 deg true and is LOS. The CN tower is at 156 deg true (14 miles) and I have it pointed probably at 175 deg true. I use it with a Philips sws2083w/17 preamp and an fm trap. For rf11 I usually get around 60 to 70 on the signal meter. I was also hoping to get CKVR rf 10 from the backside. For that station the NM is 13 with a distance of 37 miles at 345 deg true and the signal is 2-edge. Unfortunately for this signal I only get about 10 to 15 % on the signal meter (needs about 40 for decode). For this signal I made a K6STI 5-element yagi which gets the signal up around the 45 to 55 range.

The UHF performance of the KROSS is ok as well. I don't have a problem with any local signals including Hamilton's rf36. The stronger Buffalo channels come in good as well ( around 90 miles). I only have trouble with 2 Buffalo channels at my location. They are 17 rf43 and 29 rf14 (around 60 miles). I was having trouble with 17 on my SBGH in the summer but it has now stabilized for the most part. I've never really had luck with 29 but recently found a hotspot for it. I will try to use the KROSS for that since that same spot seems to be good for 11 as well( but not 17). Since I was running a parallel analog installation before the change I am using those lines for the KROSS. My strategy is to maximize the SBGH for 17 and the KROSS for 11 and 29. I'll then use an A-B switch as needed.

Finally there are a couple of other channels that I don't get which are ION 51 rf23 which is tropo according to TVFOOL and 26 rf26 TCT which is -16 NM and 2-edge but i've never had much luck getting it consistently (100 miles).

Anyways, I got the KROSS for $10 on sale (couldn't resist). I think for anybody in the GTA who is having trouble with channel 11 and 9 its worth a try. Cheaper and more potential then the ANT2084 I would think.

I also did the the fan thing as well. Works great up in the attic. So my suggestion to you is to throw it up into the attic if you have one.

Also, I would be interested to see any mods that you come up with. Any quick mod that would help with low UHF would be nice too. I was thinking of trying something to beef up VHF-HI from the back but it would probably wreck the rf11 reception as it is. CTV2 is putting a repeater on rf35 in Hamilton so i'll wait for that instead. In the meantime i'll use the K6STI Yagi for it if I need to. It's currently pointed at WBBZ monitoring signal levels.

Thanks for posting. I knew it was the better choice for a cheap 4-bay due to its VHF-HI potential. I'm glad others see it as well and hope other members who have one will let us know how it is working out for them.

[300ohm]

Before the transition I thought my attic mounted SBGH gen1 would be able to get rf11. Of course that didn't happen so I used one of these to see if I could get rf11, which it does a pretty good job of off the side.

For the SBGH to get rf 11, put a 28" NAROD above and below the stubs separated by a 1/4" to 5/16" airspace. With the NAROD, I think you should get rf 11 stronger than with the Kross.

http://www.digitalhome.ca/forum/showthread.php?t=99907

[mrpeter105]

Originally Posted by 300ohm

For the SBGH to get rf 11, put a 28" NAROD above and below the stubs separated by a 1/4" to 5/16" airspace. With the NAROD, I think you should get rf 11 stronger than with the Kross.

http://www.digitalhome.ca/forum/showthread.php?t=99907

Hi:

Thanks for the tip. I might do that. Gotten a bit lazy I guess. At the time the KROSS was the expedient thing to do. I had bought it for my dad but when I couldn't get rf11 decided to try it and see how it did. Once I got it I decided to keep the KROSS. Thanks for all your efforts.

[balm]

mrpeter, good for you, sounds like it has its place even if its not optimal (to say the least),

maybe if someone gets the UHF-VHF model running we could further come up with some mods, hacks

I to have noticed there is a serious demand for the most INEXPENSIVE commercially made antennas, for specific needs of course, "nothing to lose right...."

Would be interseting to see you K6sti yagi build if you have any pics...

[mrvanwinkles]

Beautiful Saturday afternoon. I'm in Kingston over the weekend. Just thought I would check in.

300ohm, post #23 - about the phasing lines connecting 1/2" in on the bowties - thereby shortening their effective length (?)

and Bouval, post #30 - the internet link at the bottom, to the photo with the plastic whisker caps off - shows it.

YA - good point / great idea. So if a MOD were easy to re-mount and narrow the separation of the phasing lines, and connect right at the point of the whiskers inside the caps, instead of 1/2 inch in ... then you might gain some whisker length - maybe easily that way. (Turn around the metal clip and secure somehow like that?)


A few HACK ideas I have:

1. Insert some short AL rod pieces into the whisker tube ends and crimp (or weld with that low temp AL brazing rod). thereby increasing the whisker lengths a little. Ex - AL wire, or some AL siding nails (easy). Leave the "HEAD" of the AL nail - because a larger end may also increase the "effective electrical length" of the whisker.

2. Insert an aluminum round piece piece at the ends of the whiskers. Larger tip at the end may increase the "effective electrical length" of the whisker.
ex. cut a circular piece of AL siding / maybe the size of a penny with a tip to insert in the whisker end - and crimp or weld.
ex. Thin AL washers? Cut slot in end of whisker w/hacksaw, insert washer and AL braze.

3. Similarly, the reflector ends could be easily extended some - in a similar way.

(any AL you try to connect, has to be polished up where it connects / sanded so it makes good electrical contact - of course)

(closing the ends of the tubes in this way will also prevent any outdoor wind whistling)

4. To improve VHF-HI. I attempted to improve VHF hi by placing a longer yagi style reflector rod behind the 29 inch folded dipole. This will also make it directional to the front. I believe I improved ch 13 , when it was still analog, by adding some sort of reflector - a bit clearer analog picture. (Directors in front I could not notice much difference and probably interfered with UHF signal in front - not sure - modelling could try and confirm).

(approx length of the yagi reflector and distance back, I got some values by running a CH 13 yagi design on Martin Meserve's K7MEM? website / yagi calculator. But just by experimenting - anything longer than the 29 inch folded dipole seemed to help - and maybe 8 or 9 inches behind the dipole just from memory. You could experiment with just about anything metallic / that conducts.)

5. Increasing the separation between the whiskers and the reflector grid.
- might not be so easy. Some plastic extenders, or spacers of some sort?
(worth the trouble? not sure.)

Computer modelling of these HACK MOD ideas might give some confirmation and suggest some guidelines for some "optimum" lengths, spacings or sizes.
... or to see if it is even worth the trouble.


My KROSS antenna in Ottawa is at a different location to my current work location - not so easy to get access to it now. I work at a different site during the week now. So it's not easy for me to experiment practically - unless I go purchase another one.

I left it there for the guys to continue to enjoy and use there.
Fan stand, antenna, and all.

Seemed the best thing to do.

[BOUVAL]

Insert some short AL rod pieces into the whisker tube ends and crimp

#8 AWG fits perfectly in those tubes, so you just crimp a little.
.

[balm]

When I mentioned brazing/soldering aluminum angles, tubes, rods, the employee at HD, who is very knowledgeable by the way, basically said I'm kidding myself trying to braze aluminum (welding is another matter). He said "aint no way - not with any low temp aluminum imaginable"

I told him I saw it on youtube, using the higher strength torch (not the welding equipment). He laughed and said he challenges me to succeed

[300ohm]

Well, you need alumna rod.
http://aluminumrepair.com/land/index...FchM4AodcUIRdA

At Harbor Freight, they have something similar. Its not cheap either, something like $14 for eight or so sticks. Im not sure how well it would do on wire.

[balm]

Yep, I mentioned him that specifically, but I guess he got high on his horse and just dug in at that point

Anyway, price or work wise, doesnt seem to feasable for home made work...

[mrpeter105]

Originally Posted by balm

mrpeter, good for you, sounds like it has its place even if its not optimal (to say the least),

maybe if someone gets the UHF-VHF model running we could further come up with some mods, hacks

I to have noticed there is a serious demand for the most INEXPENSIVE commercially made antennas, for specific needs of course, "nothing to lose right...."

Would be interseting to see you K6sti yagi build if you have any pics...

Thanks. It doesn't have to be optimal it just has to work good enough to keep me happy.

Actually I do have some pics. I bought my first camera last year so I don't know too much about photography and such. I haven't used it too much. However I did take some pics of my antennas. They turned out ok, just point and click. Anyways right now i'm investigating how to reduce the file size and also how to resize the pics for displaying on the webpage. Then once I get that figured out I have to figure out how to upload them to DHC and then posting them. I'll probably post them in the thread about showing your setup I guess.

[300ohm]

Anyways right now i'm investigating how to reduce the file size and also how to resize the pics for displaying on the webpage.

Imageshack.com, a free place for picture storage, will automatically resize the pictures for posting here on upload. After uploading to Imageshack, just put the direct link address in the post using the [IMG] [/IMG] tag.

Example: [IMG]http//:imageshackdirectlinkaddress.jpg[/IMG]

[mrvanwinkles]

Bouval - Great,

Bouval, Did you actually do it ? Install extensions with #8 GA AL ?

So if #8 AWG ( 8 Guage ) AL wire fits (& crimp) - it's a possible easy mod.

And not much material required.

Crimp? Vise or vice grips? Good pliers?
Idea: Remove whisker, Insert extensions, TAP oval on a flat anvil/heavy flat strong surface/concrete floor, and "TAP" oval with hammer?)

Hopefully they stay put / don't move. That - and long term corrosion / long term connection quality concern me - that is why I suggested an ALU-Rod type product spot "BRAZE". I have not tryed an AL braze yet myself, must experiment / practice some time - I purchased some special rods for that purpose. They say takes around 700 deg Celcius - and possible with simple propane torch. Not sure.

( I actually have a coil of some AL wire in K'Town at house there - maybe around that size ! I will have to measure it and see what it really is.)
( It might be / have been, common stuff for some use. Old AL electrical wiring? AL Ground wiring? )


EXTEND WHISKERS OUT STRAIGHT HORIZONTALLY ?

After I thought some more, I realized there's probably not much room between whiskers above and below for extensions. Bay spacing is close. Adding extensions might mean the whisker tips could get very close or even cross.

So what about a slight bend and extend straight out ? Horizontally?

(I understand some whisker antennas actually do something like that. But then I guess they would not be "true" whiskers then, would they ?)

sort of like:

._____
/

\_____

So what are we talking then ?
TWO INCH WHISKER EXTENSIONS ? Around that ball park?

( And modelling? Will it improve anything? Low UHF? Is it worth doing? Or are we just fooling around? )

( ! Now I wanna go buy another KROSS antenna - just to experiment. I'm such a HACK. )

[300ohm]

sort of like:

._____
/

\_____

Yeah, you can do that. Also, by closing the ends of a bowtie, making it a closed end bowtie, you effectively add about 1/2" of whisker length over an equivalent open whisker.

[mrvanwinkles]

Another obvious idea that I should mention:

Just remake all the whiskers complete from suitable copper wire or small tube.

And the phase lines too. A good idea since copper and AL metals - contact and connections - may not mix well.

In which case, soldering copper is much easier than brazing AL.

And then, you can solder your phase lines to the very tip of the whisker bends - and possibly gain that "lost" 1/2" whisker length too.

And this way - also - you retain all the original AL parts without modification.

(the way the original antenna is ... it seems to work better on mid to upper UHF - and you can always go back to that - if it suits your situation / needs)