Advice about base civ/mil airband antenna - Diamond D777 or Comet AB380

[flanker86]

I would like to buy one of those two base civ/mil airband antennas for my Airspy R2 and I am considering Diamond D777 or Comet AB380 (twice as much money as Diamond).
What is your opinion and experience about those two.

 

[Ubbe]

It seems impossible to get any technical data of the Comet. The Diamond are longer and have enough space for a 5/8 antenna for VHF and says 3,4dBi and for UHF it is 2x5/8 with a 5,5dBi gain.

/Ubbe

 

[flanker86]

Here are both tech specs.
This is from Comet catalogue:


An this is from Diamond cataogue:

 

[iMONITOR]

The Diamond D777 is not impressive, almost seemed deaf. It's overpriced and last I checked not even sold in the U.S., probably for a good reason.


Consider DPD Production's
MilTenna Omni UHF/VHF Base Antenna

MilTenna Omni UHF/VHF Base Antenna

Specs Gain: 3 VHF 4 UHF dBi Pattern: Omni-directional Wavelength: 1/2 Elements: 3 Tuned: 225-400, 118-137 & 138-140 MHz Band: UHF & VHF Air Connector: N Female Cable: RG8X Cable Length: 24 Inches Height: 45" Width: 30" Weight: 2 lb Features Tuned to UHF & VHF Air Bands: The uniquely...

dpdproductions.com

Or the Diamond D130J N discone.

Invest in an FM-Notch filter as well.

 

[flanker86]

Probably it is very good, but the minus is that I live in Poland, Europe - and shipping is $78.89 (cost of D777 alone) and customs must be also taken into consideration...

 

[MDScanFan]

I have not used either antenna listed but I can't imagine they would give good performance across the full VHF/UHF airbands. As the specs imply, they likely have sweet spots in both bands but poor performance elsewhere. I would not be surprised if they have at least 10 dB of mismatch loss at the edges of the bands.

I second the suggestion to look into getting a discone antenna. They will do a much better job of getting good average performance across vhf/uhf airbands than the antennas you listed above. Do you have those available locally?

 

[vagrant]

As previously mentioned, a discone type of antenna will cover the wide frequency ranges you want. Add an FM Broadcast band filter inline on the coax as well to suppress interference from nearby/strong radio stations. At that point after testing, you may want to add a low gain amplifier around 10dB or less. Still, you may be fine without the amplifier. It would be odd if you are unable to find a discone antenna in Poland.

The really important part is getting the antenna outdoors and above your roofline.

 

[flanker86]

Yes - I am already using a Diamond D190 discone on my balcony connected to Uniden UBCD3600 XLT (European version of bcd436hp) for known frequencies and a Scanstick mobile antenna on my external window sill connected to Airspy R2. Both have FM filters attached. But the downside is that it is block of flats and it is not the highest floor - that is why I have only about 180-200 degrees coverage. My parents live in a house in a rural area and I would like to install the new antenna there to have full 360 degrees.

Here is a SWR chart of the Scanstick from a polish radio forum:


And here is a youtube screen of SWR of D777 by - ironically - a polish guy living in UK - but only on Civ Airband - it looks not bad...

 

[MDScanFan]

Why not just get another discone antenna for that new location? It is hard to beat a discone for broadband coverage and a stable and predictable radiation pattern.

 

[vagrant]

I should have been specific about the Diamond discone, like the D130 or the D3000. Those other Diamond discones with shorter elements will not work as well in the lower airband range.

 

[flanker86]

I can use a discone, not a problem, but I thought a "dedicated/tuned" civ/mil airband antenna would perform much better on those bands than a general purpose wideband discone...

I am still opened for reviews - either good or bad - for those antennas from title.

 

[Ubbe]

If you look at that Comets transmit range of 1,5MHz, that's +/-10% which is the same as a standard 1/4 wave antenna. So the antennas are probably not special wideband antennas, just normal dual band. When you increase the diameter of the elements you gain some bandwidth, but not much.

The 3:1 SWR at the band edges of VHF equals to a 25% loss but a 5/8 or 1/2 wave will still have a higher signal than a discone. It's more to the discones favor in UHF as that bandwidth are a bigger percent of the frequency and the other antennas will have a bigger SWR at the band edges. But then both antennas use a 2x5/8 UHF design that have much higher gain than a discone that will probably compensate for any high SWR losses.

I wouldn't think that anyone have both a Diamond and a Comet to be able to compare but there has to be several who have either one and also a discone with the same type and length of coax and antenna hight.

/Ubbe

 

[Kiniutech]

Dzien Dobry,
Prosze zobaczyc stary thread na ten temat.
Aircraft band base antenna
Chyba Sirio Air Band jest do dostania w Polsce taniej

https://allegro.pl/oferta/sirio-gp-108-136-u-antena-bazowa-na-pasmo-lotnicze-11055145644

https://allegro.pl/oferta/sirio-sd-1300n-antena-discone-do-skanera-1300mhz-n-11027282715

https://allegro.pl/oferta/antena-szerokopasmowa-do-skanera-sirio-sd-1300-11389554063

Tansza niz Diamond D130


Krzysiek

 

[flanker86]

Dzien Dobry,
Prosze zobaczyc stary thread na ten temat.
Aircraft band base antenna
Chyba Sirio Air Band jest do dostania w Polsce taniej

https://allegro.pl/oferta/sirio-gp-108-136-u-antena-bazowa-na-pasmo-lotnicze-11055145644

https://allegro.pl/oferta/sirio-sd-1300n-antena-discone-do-skanera-1300mhz-n-11027282715

https://allegro.pl/oferta/antena-szerokopasmowa-do-skanera-sirio-sd-1300-11389554063

Tansza niz Diamond D130


Krzysiek

Dzięki, ale oprócz airbandu 118-137 potrzebuję na równi 225-400./
Translation:
Thank you, but besides airband 118-137 I need equally 225-400.

 

[spanky15805]

DPV-39 VHF/UHF Dual Band Antenna Omni 118-137/225-400 MHz

 

[vagrant]

The DPV-39 would have a high cost to ship, as well as purchase.

 

[prcguy]

I have one sitting in the rafters of my garage. $75 takes it but shipping would be a lot.

The DPV-39 would have a high cost to ship, as well as purchase.

 

[Ubbe]

When I look at the DVP-39 it consist of one 0dBi dipole for VHF and one 0dBi for UHF that has their own antenna connector, one for VHF and one for UHF. You would need a diplexer to combine them.

/Ubbe

 

[vagrant]

Rather than a diplexer, I would simply use a second receiver/scanner and reduce the missed transmissions. A Uniden BCT125AT is around $100 U.S.

When I look at the DVP-39 it consist of one 0dBi dipole for VHF and one 0dBi for UHF that has their own antenna connector, one for VHF and one for UHF. You would need a diplexer to combine them.

/Ubbe

 

[iMONITOR]

For your UHF Mil-Air setup you might want to consider a band pass filter too.

Receive Filters