DIAMOND 3000 Superdiscone

[wv2vvl]

I'm very pleased with the reception I've gotten from this antenna, especially below the specification bottom end of 25 MHz. I routinely am able to copy clear channel station KDKA in Pittsburgh after dark & they are on 1.02 MHz. Before getting my ham ticket I spent a lot of time SWL with this antenna & had excellent reception on any frequency from 1 to 1K MHz, a fact which puzzles & astonishes hams who are not familiar with this kind of antenna.

Before final assembly & getting it outdoors, I had it leaning against my basement wall with only 3 radials installed & it still worked great.

Jack
NE PA

 

[bearcatrp]

Am enjoying mine

 

[ka3jjz]

More than likely you are getting top loading with the coax just acting like its own antenna....Mike

 

[wv2vvl]

More than likely you are getting top loading with the coax just acting like its own antenna....Mike

Whatever. The antenna still performs beyond my expectations so I'm not going to waste any time trying to 'fix' it.

Jack

 

[bearcatrp]

I thought this was a joke listening to HF but just checked it out and compared to a wire I have up. Performed the same or even better than the wire. Going to do another test tonight to verify. If it does as good as today, the wire is coming down. Just listened to a EAM on 4.724 and it was pegging the S meter. I was shocked. Just used mine for air band and other stuff above 25 mhz until I tried this.

 

[wv2vvl]

I thought this was a joke listening to HF but just checked it out and compared to a wire I have up. Performed the same or even better than the wire. Going to do another test tonight to verify. If it does as good as today, the wire is coming down. Just listened to a EAM on 4.724 and it was pegging the S meter. I was shocked. Just used mine for air band and other stuff above 25 mhz until I tried this.

Glad I was able to show you what I knew what antenna could do for you if you only tried it.

Jack

 

[vagrant]

For anyone who reads this thread and suddenly thinks that particular discone will perform well in the HF bands....hearing that 50,000 watt AM station at night is not unusual. "With a good radio, KDKA can be heard in much of the Eastern United States and Eastern Canada at night". Still, if one is happy with the result that is what matters. I am not trying to rain on your parade, but people need to set their expectations appropriately.

As to the wire not performing as well as the discone, I encourage you to check your wire setup for problems first and then at least testing/comparing using the time broadcast station frequencies in the U.S.A. and Canada.
WWV
WWVB
CHU

 

[MDScanFan]

Has the OP compared the discone to an antenna designed for HF? It's always nice to have something else to compare to. I am happy it is working out for you.

 

[wv2vvl]

Has the OP compared the discone to an antenna designed for HF? It's always nice to have something else to compare to. I am happy it is working out for you.

The specs call for a bottom working limit of 25 MHz. I never tested it below 1.02 so I will add that to my list of interesting projects.

 

[bearcatrp]

For anyone who reads this thread and suddenly thinks that particular discone will perform well in the HF bands....hearing that 50,000 watt AM station at night is not unusual. "With a good radio, KDKA can be heard in much of the Eastern United States and Eastern Canada at night". Still, if one is happy with the result that is what matters. I am not trying to rain on your parade, but people need to set their expectations appropriately.

As to the wire not performing as well as the discone, I encourage you to check your wire setup for problems first and then at least testing/comparing using the time broadcast station frequencies in the U.S.A. and Canada.
WWV
WWVB
CHU

And just how do I check my wire setup? I use the balum from and end fed antenna. I run 40 feet of wire about 30 feet into the trees going north and south. Anything else I should be checking? I ran the same wire last winter without issue. But, for the same signals from different distances showing the discone better, I will go with the discone so far. I will test it tonight when conditions are better to confirm what I found out today. Plug into wire, find a good stead station, unplug, plug in the discone. Should tell the tale.

 

[bearcatrp]

Did the test tonight. Came out the same. Discone performed as good and even better than my wire on different frequencies below 25 MHz. Looks like my wire is coming down.

 

[wv2vvl]

I added the following USAF global comm channels to my ICOM 8600 just now in order to evaluate the discone's performance on HF. There were strong carriers on each of the 6 USB channels:

4.724 S2
6.769 S4
8.932 S6
11.175 S6
13.200 S6
15.016 S6

On SCAN the receiver stops on each channel for 10 sec. I can squelch these out but that lowers the sensitivity on all the other channels. But this shows how well the discone works on HF signals over a very broad range.

I tested the discone below 1 MHz midday. I will test again tonight when propagation will be enhanced.

AM broadcast band below 1 MHz:

0.830 S4+
0.800 S6
0.79 S4+
0.77 S4+
0.71 S7
0.66 S3+
0.64 S6+
0.61 S7+
0.56 S8
(several weak stations not included)

FAA airway beacons:

0.363 RNB 'RAINBOW' NDB Robbinsville, NJ S0 CW ID 11W 34.1 miles away.

I'm very satisfied with the performance of this antenna. Reception below 400 kHz was unexpected but welcome. As with any antenna, performance has peaks & valleys in different bands. I haven't used it for transmit yet but plan to check it out on 28.4. Just read over the instructions for the automatic antenna tuner in my ICOM 7300 so I might give it a try on reduced power (5W or so).

Jack

 

[bearcatrp]

Any more tests Jack?

 

[wv2vvl]

Any more tests Jack?

Not scheduled. My project today is to make progress on a dipole for 10M SSB (28.4). I have all the parts + an MFJ antenna analyzer. I also plan to erect a vertical dipole for 10M FM (29.6). So I have other projects ahead of any further tests.

I've used the discone for receive on 363 kHz & 1.09 gHz, so I'm satisfied for the moment.

Jack

 

[prcguy]

I've occasionally used a Discone for HF reception for at least 30yrs and although it picks stuff up it is a big compromise. Since HF reception is driven by signal to noise ratio even a very weak signal with virtually no noise can be pleasant to listen to.

A Discone would be operating in a "voltage probe" mode where the disc and top whip are more of a capacitor than an antenna element and they are very high impedance in the lower HF range and very lossy due to the massive impedance mismatch. If you could place a broad band transformer like a 50"1 or greater ratio between the disc/whip and feedpoint you would get more signal into the coax.

 

[ratboy]

I used to pull the PL-259 partway out on my CB antennas so the shield was the antenna. It worked very well. Sometimes better than my Slinky dipole, and my Alpha-Delta sloper, which both worked better than the dipole in my attic.

 

[superman2112ms]

I added the following USAF global comm channels to my ICOM 8600 just now in order to evaluate the discone's performance on HF. There were strong carriers on each of the 6 USB channels:

4.724 S2
6.769 S4
8.932 S6
11.175 S6
13.200 S6
15.016 S6

On SCAN the receiver stops on each channel for 10 sec. I can squelch these out but that lowers the sensitivity on all the other channels. But this shows how well the discone works on HF signals over a very broad range.

I tested the discone below 1 MHz midday. I will test again tonight when propagation will be enhanced.

AM broadcast band below 1 MHz:

0.830 S4+
0.800 S6
0.79 S4+
0.77 S4+
0.71 S7
0.66 S3+
0.64 S6+
0.61 S7+
0.56 S8
(several weak stations not included)

FAA airway beacons:

0.363 RNB 'RAINBOW' NDB Robbinsville, NJ S0 CW ID 11W 34.1 miles away.

I'm very satisfied with the performance of this antenna. Reception below 400 kHz was unexpected but welcome. As with any antenna, performance has peaks & valleys in different bands. I haven't used it for transmit yet but plan to check it out on 28.4. Just read over the instructions for the automatic antenna tuner in my ICOM 7300 so I might give it a try on reduced power (5W or so).

Jack

I havean old RS discone without the verticle Element. With tax time I was going to improve a few things. First and formost proper coax for the discone. (have 2 or 3 pieces of cheap coaxLoL.) would you upgrade the discone to a diamond or spend the money on other hardware? (multicoupler, yagi ffor simulcast issues etc.) I am not looking for high tech details just a simple yea probably or no.

 

[Marcy57]

I like my Diamond 3000 but I do not ever think I used
for HF listening? ...the Loop and T2FD is for that, 73,s
Marcy ...( gotta add I think I tried it once and it picked
up WWV on 20 quite well but lower than that not good!)