DV1 Poor Sensitivity

[2e0jva]

Hi, l’ve just bought an AOR DV1 and l’m just playing around with it.
l’ve notice compared to my AOR 3000A especially in AM on the air bands the 3000A picks up signals that the DV1 cannot hear.
Is there a setting some where, where the sensitivity can be adjusted, and when scanning in AM what’s the best bandwidth to set the receiver too?

 

[AOR-262]

@2e0jva

This reply doesn't answer your question but as you've mentioned sensitivity and a comparison between two receivers, here's a video of my comparison of my AOR 8600 Mk2 vs Icom IC-R8600 receiving AM memories.

 

[marlbrook]

Hi, l’ve just bought an AOR DV1 and l’m just playing around with it.
l’ve notice compared to my AOR 3000A especially in AM on the air bands the 3000A picks up signals that the DV1 cannot hear.
Is there a setting some where, where the sensitivity can be adjusted, and when scanning in AM what’s the best bandwidth to set the receiver too?

The AOR Manual says any signal attenuation on the AR-DV1 is 'automatic'. It has no manual adjustment. 'Attenuator function is always activated automatically and no attenuator indicator is displayed on the LCD screen'.

Page 25 (4-3) explains the RF Gain function, but in tests that should not be engaged, using the 'fast' AGC level for the frequencies you mention. For Aircraft AM transmissions an IFBW of '8' is appropriate.

One person had a similar problem but that proved to be a dirty BNC connector (in his case the socket on the Radio, cured with Switch Cleaner).

It would be interesting to know exactly how your experiment was conducted?

Without a stable Signal generator the only way of removing most if not all unwanted variables would be to run both Receivers at exactly the same time, each monitoring the identical specific Frequency with the Squelch 'OFF' in VFO Mode, and using just ONE aerial connected to each Receiver via a Splitter. Then swapping the leads to each Radio over and repeating the tests, to remove any possible disparity in the Cables / BNC plugs from the Splitter.

IFBW should also be the same. Using a 'moving' Aircraft signal the comparison MUST be observed / monitored at exactly the same time naturally.

Minor differences in 'S' readings between any two Receivers (even the same Model) can always be expected.

 

[2e0jva]

The radios were side by side monitoring the same frequency.
They both had identical telescopic antennas and the 3000A was out preforming the DV1.

 

[marlbrook]

@2e0jva

This reply doesn't answer your question but as you've mentioned sensitivity and a comparison between two receivers, here's a video of my comparison of my AOR 8600 Mk2 vs Icom IC-R8600 receiving AM memories.

Looking at the comments on YouTube it appears the Radios were connected to different aerials (described as identical) during the experiment.

The video is interesting, and well presented, but in reality the comparisons have no credibility whatsoever, given the chaotic nature of radio signal propagation / reception.

Different aerials, no matter how similar, in what has to be different locations to a greater or lesser degree, and even using different cables makes a truly accurate comparison totally impossible.

Without strict measures to remove all possible variables differences one should be VERY wary of drawing any conclusions from this or any similarly conducted comparison..

 

[marlbrook]

The radios were side by side monitoring the same frequency.
They both had identical telescopic antennas and the 3000A was out preforming the DV1.

Well that answers that then. Yours would seem to be conclusive results.

Personally, with my limited experience, I envisage problems using different aerials in different locations. In Radio the slightest difference in location, even outdoors and especially indoors can produce wildly different results. I have an Icom handheld. With its telescopic whip in one spot on my desk it can hear a local Taxi signal at S9. Twelve inches to the right and it gets no signal at all.

It may be that your AR-DV1 BNC socket might benefit from a squirt of Switch cleaner though.

I have an AR-DV1, AR3000, AR3000A, and AR8600MKII. I have not noticed any particular difference in sensitivity on the Aircraft Bands, but I certainly have not conducted close and balanced tests using the same Antenna split between each, at the same time. Unless I did that (as previously described) I would never be able to draw specific conclusions about their sensitivity. Many might disagree no doubt, and be sure different aerials, in different locations have little or no relevance in achieving accurate and balanced results.

 

[Andy3]

I have a DV-1 and it's every bit as sensitive as my other receivers. I have 4 rooftop antennas for various bands and a low-loss switch-box in the shack which can route any antenna to any RX and there's nothing to choose between them for sensitivity.
I agree with the comments about not relying on tests which use antennas in different sites. On VHF (moreso on UHF) just a few inches one way or the other can make a big difference.

 

[buddrousa]

Years ago and still to this day you could take the same AM TRANSISTOR RADIO put it on a dresser move it 5 inches and lose the signal.
The only way to fairly compare 2 receivers is on a good multicoupler with the exact same cable length going to each receiver.
Receiver 1 may be interfering with receiver 2 sitting side by side with inside antennas.

 

[dlwtrunked]

Hi, l’ve just bought an AOR DV1 and l’m just playing around with it.
l’ve notice compared to my AOR 3000A especially in AM on the air bands the 3000A picks up signals that the DV1 cannot hear.
Is there a setting some where, where the sensitivity can be adjusted, and when scanning in AM what’s the best bandwidth to set the receiver too?

When making a comparison like this, one must take into account that different receivers will suffer different amounts of de-sensing from nearby FM broadcast stations. And keep in mind one will not hear the FM broadcast station if this happens--but the radio will be less sensitive than otherwise it would be. Do you use a good FM broadcast block (like one by Mini-Circuits)? For many listeners, such a filter is a must even though they have no idea that they need one.

 

[marlbrook]

The only way to fairly compare 2 receivers is on a good multicoupler with the exact same cable length going to each receiver.

From my other posts in this thread I obviously agree, with the added double-check of completing one set of tests, then swapping the two cables going to the Receivers, and repeating the tests again. Just to eliminate the possibility of any difference in the cables / multi-coupler's performance.

The original thread was also using AM Air Band signals. Unless they were from fixed ground stations, then the fact that the Aircraft signal positions were also moving makes direct comparisons even more unreliable using two Receivers with only similar aerials and in different positions (no matter how slight) .

On the face of it the original 'tests' sound reasonable, but although doing 'ad-hoc' testing without taking into account these type of variables may seem OK, but drawing conclusions from them is very unreliable at best.

 

[Ubbe]

Diiferent receivers/scanner can behave differently depending of the enviroment and needs to be used where they function the best.

If I have an $150 Icom R2 portable and a $300 Uniden UBC3500 portable sitting on the table with their own antennas, the R2 are very obvious to have a better receiver sensitivity and at most frequencies will outperform the 3500.

When I connect them to a roof antenna the 3500 pick up way more signals than the R2. Measuring their sensitivity when they are directly connected to a signal generator gives something like a 0,15uV sensitivity for the R2 and 0,35uV for the 3500. When they are connected to a roof antenna and measured with a 30dB T-connector the 3500 measures a 0,8uV sensitivity and the R2 around 12uV. Using a FM trapfilter changes that to 0,5uV for the 3500 and 2uV for the R2.

Dependiig of the RF enviroment one receiver could work better than another but could be the opposite when tried at a neighbours house or just by switching their places on the table so that the signal from a nearby tower are blocked more and do not de-sense the receiver. So it could be either that you do not receive enough signal from a position on the table or it could be too much signal and it depends of how the receiver handles RF signals and basicly how the company designed the receiver to be used and how much they spent on quality components.

So the Icom are not suitable to be used with big antennas but will work splendid most of the time at a low signal enviroment, like indoors using a rubber duckie.

Most cheaper radios/scanners are a compromise between sensitivity and interference rejection and cannot do both. It costs money to produce a receiver of good quality. You can look at the Icom8600 that has a resonable good receiver but with a list price of $3000.

/Ubbe

 

[rumcajs_tr]

The problem may be in the damaged DV1 front end. About two years ago I had a DV1 that I bought second hand. Immediately after connecting to my antennas I noticed a worse sensitivity to the UHF band. In the HF and VHF bands the sensitivity was excellent, comparable to ICOM receivers, but in the UHF bands DV1 received very poorly. So I took DV1 on the radiotester and measured the receiver sensitivity. According to the specification, the sensitivity should be 0.32uV (12 dB SINAD) in the 18-1300 MHz band. In fact, I measured a much better sensitivity on VHF, between 0.22uV and 0.25uV (in the 118-174MHz range). Unfortunately, the measuresd UHF values exceeded 0.55uV, which had huge impact on the reception. I contacted my local radio shop asking for repair, but since this item was no longer under warranty, I didn't want to invest money in it and I eventually sold the DV1 in this state. Maybe after my experience I would recommend measuring the sensitivity of your piece on a professional radiotester. If you have a DV1 under warranty, I strongly recommend trying a warranty service.

 

[marlbrook]

The problem may be in the damaged DV1 front end.

That is a possibility of course, but I strongly recommend anyone who thinks there are having the type of problem you mention to first see if there is a 'dirt' problem with the DV1's BNC aerial socket. Just a quick couple of sprays of Switch cleaner, inside the socket (particularly the centre 'hole'), and on the BNC plug, then inserting and re-inserting the plug a few times.

I know it sounds just 'too simple', but a corroded or dirty BNC socket can definitely cause problems, and 'Nature' is quite happy to create a bad connection all by itself.

 

[DeepBlue]

Also, there are different squelch types available in the DV-1. I cannot recall but I believe almost every report and I think even AOR themselves recommends using the LSQ function vs any of the others. I am using it right now on Air band here and am hearing Mil Air out to almost 150 miles at lower altitudes playing in Southern Ohio from Columbus.

Could be dirty BNC connector too, or bad connector on your cable, adapters, etc.

Sean
KB8JNE

 

[m0taz]

Something that occurred to me, if your using a BNC adaptor to x then these cheap Chinese adaptors are notorious for loss, more pronounced at UHF. I have a VHF antenna that is terminated in PL259 and I used a cheap BNC adaptor, something I need to check on for my own UHF reception.

Dave

 

[Andy3]

I have an DV1, a R&S EB150 and a Winradio SDR and all are fed from the same set of rooftop antennas via a splitter. Reception of airband is the same on all three radios. I use the airband VOR beacons for this test as they are quite low-level, stable signals and I can't say any one radio performs better or worse.