jj130 HF antenna???

[ridgescan]

....fartin around this morning, I hooked my Diamond discone to the R75-all I can say is WOW!!! Anyone here have a J130 and a SW radio-hook 'em up and tell me what you found





EDIT: tried to take out one of the Js in the title-stupid wireless keyboard skips a lot-anyways the antenna is a Diamond J-130.

[k9rzz]

I don't have that antenna nor radio, but I do listen to HF with my IC706mkIIg in the mobile with a 5/8 wave 2m whip. I can hear a lot without a 6ft antenna perched on the roof (that turns heads I tell 'ya! LOL).

[ridgescan]

Originally Posted by k9rzz

I don't have that antenna nor radio, but I do listen to HF with my IC706mkIIg in the mobile with a 5/8 wave 2m whip. I can hear a lot without a 6ft antenna perched on the roof (that turns heads I tell 'ya! LOL).

....I assume you meant to say with a 6' antenna right? That's neat stuff I am totally amazed at how this antenna performs on SW! I have a Ham Radio Outlet catalog and on the "SW listening" page they have, along with the log periodics and longwires etc., a J130 Diamond Discone which I always thought was a scanner antenna alone-even states "for 25-1300MHZ"-so rather than call, I hooked mine up to see why they'd group it in on this page-not only do I get great reception but this antenna actually lowered the noise floor from around 15-20 down to 3-10! THAT opens up a whole bunch of new discovery!! And I dont have to kick on all the filters like before. Just thought I'd throw that one out there for those of you who have space issues but want a great HF getter
http://s295.photobucket.com/albums/m...t=MVI_0119.flv
...here is the J130 at work!

[prcguy]

I occasionally use a discone in a pinch for HF reception and it can work ok. A very small antenna can be 20-30dB or more down from a full size dipole and as long as the signals are relatively strong you can still have a similar signal to noise ratio as the larger antenna but with much less perceived noise.
prcguy

[ridgescan]

Originally Posted by prcguy

I occasionally use a discone in a pinch for HF reception and it can work ok. A very small antenna can be 20-30dB or more down from a full size dipole and as long as the signals are relatively strong you can still have a similar signal to noise ratio as the larger antenna but with much less perceived noise.
prcguy

That must be what I am experiencing here. I tell you this antenna's performance suits me just fine as you can see in my little link above-it gives me a good reliable CLEAN signal. I am surprized I haven't heard more on this.

[prcguy]

If you have a very short run of low loss coax to your discone it will help preserve signal levels on HF because of the really high impedance of the short elements at HF and the additional coax losses above and beyond the advertised coax loss.

I have a Yaesu VR5000 which is fairly sensitive but overloads quite easily with a large HF antenna. On the rare occasion I use the Yaesu its usually connected to a discone to avoid overload and reduce some of the noise this annoying little radio has on HF.
prcguy

Originally Posted by ridgescan

That must be what I am experiencing here. I tell you this antenna's performance suits me just fine as you can see in my little link above-it gives me a good reliable CLEAN signal. I am surprized I haven't heard more on this.

[k9rzz]

[QUOTE=ridgescan;1021984]....I assume you meant to say with a 6' antenna right? That's neat stuff/QUOTE]

Re-phrase: I can hear plenty with the 2m 5/8 wave without having a 6 ft stick on the roof. Certainly the big antenna is better, and then I can transmit as well, but believe it or not, in spring I was copying a KH6 station from Hawaii on 80 meter CW as I drove across northern ILL using just the 2m antenna. He wasn't loud, but he was solid for 30 minutes. I'm sure with the 'real' 80 meter stick, I could have worked him.

[ridgescan]

Originally Posted by prcguy

If you have a very short run of low loss coax to your discone it will help preserve signal levels on HF because of the really high impedance of the short elements at HF and the additional coax losses above and beyond the advertised coax loss.

I have a Yaesu VR5000 which is fairly sensitive but overloads quite easily with a large HF antenna. On the rare occasion I use the Yaesu its usually connected to a discone to avoid overload and reduce some of the noise this annoying little radio has on HF.
prcguy

Hey when I was ready to buy a SW it was a tossup between that Yaesu and the R75-looks like I made a good choice? The Yaesu has its attributes though I'm sure-on the coax I am running 20' of RG8X-and yeah, just like you describe in your examples, the prominent improvement is the noise floor, which now has even totally gone away in some areas of the bands! It opens up a lot more chance to grab some of those obscure DXs

[quote=k9rzz;1022659]

Originally Posted by ridgescan

....I assume you meant to say with a 6' antenna right? That's neat stuff/QUOTE]

Re-phrase: I can hear plenty with the 2m 5/8 wave without having a 6 ft stick on the roof. Certainly the big antenna is better, and then I can transmit as well, but believe it or not, in spring I was copying a KH6 station from Hawaii on 80 meter CW as I drove across northern ILL using just the 2m antenna. He wasn't loud, but he was solid for 30 minutes. I'm sure with the 'real' 80 meter stick, I could have worked him.

-sorry I should have known better that's the really cool point here is that you can get reliable reception from an antenna that was totally designed for another spectrum. How big is that 2M antenna?

[k9rzz]

It's fifty four (54) inches. Certainly no slouch itself, but you should see that big 80 meter stick perched up on the roof, it's a head turner. Hmmmm, maybe I'll take a few pictures today and post 'em.