What options exist for cost effective scanning receivers for mobile and remote rural monitoring of VHF DX? Although it might seem ideal if we could always bring an Icom IC-R8500 for mobile TV DX, the relatively large weight of the R-8500 is a disadvantage. Unless one has access to a house or cottage, large VHF/UHF communications receivers are often not practical for DXpeditions and mobile DX.
A portable wideband VHF/UHF scanning receiver is more practical for many DXers. For example, Yupiteru make excellent hand-held SSB scanners. Their
best models include the MVT-7100, MVT-7200, and MVT-9000. The MVT-7100 kept Yupiteru ahead of the field when it came to high performance, wide band scanning receivers for many years. Until the arrival of the AOR AR-8000, no other receiver offered the coverage, features and performance that the MVT-7000. Although Yupiteru have introduced more recent models (MVT-7200 and MVT-9000) many still feel that even though the MVT-7100 lacks some of the more elaborate features it still leads in receiving performance. The MVT-7100 features full continuous coverage from 530khz ~ 1650MHz, including AM, Narrow FM, Wide FM, and Upper and Lower sideband.
Besides the MVT-7100, other scanners to consider include the MVT-7200 and MVT-9000. The MVT-7200 and MVT-9000 both use a Murata CFJ455K5 2.4kHz SSB filter, which provides better HF/SSB selectivity performance. If HF DX is not a priority then the MVT-7100 remains a good choice for general VHF DX monitoring.
Is the MVT-7100 suited for base and home DX monitoring? To help answer this question, a (Perth) TV DXer recently tried his Yupiteru 7100 during a double-hop sporadic E opening to the eastern states of Australia. The MVT-7100 was connected to an outdoor five element 45-70 MHz yagi
antenna. While 46.24 MHz ABMN0 Wagga was received at excellent levels on the MVT-7100, there were some spurious signals around 45 and 55 MHz.
Receivers such as the Icom 7000/7100/8500, AOR 5000, etc, have several
bandpass filters in the first RF stage. This keeps images and
cross-modulation to a minimum. However, because of the MVT-7100's small physical size, the RF front-end bandpass filters offer less overload and image rejection performance compared to a IC-R7100 base scanner.
For base station use with an external antenna, we concluded that the MVT-7100's RF front end was too broad and hence
needed a low pass filter, with a cut off frequency of ~ 88 MHz (FM band) or
64 MHz (local ch2 TV).
The MVT-7100 is more easily overloaded than the Icom 7100. In heavily
populated areas the Yupiteru 7100 can be desensitised by nearby VHF & UHF
transmitters. It is really only good for VHF and UHF DX in rural locations (which is
where you want to be anyway for DXing). It is not very sensitive on the MW
band, but good on HF. For the 88-108 MHz FM band you are probably better off using a car radio or high quality portable.
According to the reviews (i.e., strongsignals website), the MVT-7100 is the most
sensitive hand-held receiver, but easily overloaded in city areas. The 7300 and 9000 have better overload performance but are less sensitive. The MVT-7100 is great for mobile operation and DXing in remote locations without any
strong local FM or TV transmitters. The MVT-7100 is good on HF, VHF and UHF with the appropriate whip length, but useless on MW. It can't be used within several feet of a computer, as it picks up radiation through its plastic case. In a hostile RF environment like work, the MVT-7100 sometimes desensitises even on Band 1 until the offending TX/mobile phone turns off.
In summary, the MVT-7100 is excellent for monitoring of weak TV DX signals. Providing the MVT-7100 is used away from strong VHF transmitters, excellent performance will be obtained. The MVT-7100 can be found for around AU$200-$300 second-hand.
Modes: AM, NFM, WFM, LSB & USB
Increment Steps: 50, 100Hz (LSB/USB only), 1, 5, 6.25, 9, 10, 12.5, 20, 25, 50 & 100kHz (50 & 100kHz only on WFM)
0.53 - 2MHz:
AM: Less than 10uV(S/N 10db)
2 - 30MHz
AM : Less than 1.5uV (S/N 10db)
LSB/USB: Less than 1.0uV(S/N 10dB)
NFM : Less than 1.5uV (SINAD 12dB
30 - 1000MHz
AM : Less than 0.5uV (S/N 10db)
LSB/USB : Less than 0.5uV (S/N 10dB)
NFM : Less than 0.75uV (SINAD
1000 - 1650MHz
NFM : Less than 1.0uV (SINAD 12dB
- Memory Channels: 1000 (10 banks of 100)
Search Pass Channels: 500
Scan Speed: Approx 30 channels per second
Search Speed: Approx 30 steps per second
Delay: Approx 2 seconds (standard) or 5 second
- Dimensions: 64.4(w) x 155(h) x 38(d)mm
Antenna Connection: BNC Fitting
- 12 Volt External Power Jack
The MVT-7100's centre DC pin is positive. Used to connect the mains power charging
unit or DC cigar lighter lead to the MVT-7100. Care must be taken to
ensure the correct DC voltage (11-15 volts) is applied.
MVT-7100 review, which was performed by Scanners
Internationalin April 1993, provided these laboratory test results
(levels in uV at SINAD 12 db):
Frequency AM FM WFM SSB
500 KHz 3.94 2.33 - 5.13
1 MHz 1.27 .76 - 1.45
2 MHz .58 .35 - .75
4 MHz .40 .23 - .38
6 MHz .32 .17 - .27
10 MHz .26 .16 - .23
20 MHz .22 .13 - .16
30 MHz .22 .12 .36 .14
60 MHz .22 .13 .39 .14
100 MHz .21 .12 .38 .13
145 MHz .25 .16 .48 .18
250 MHz .29 .17 .73 .21
435 MHz .35 .22 .67 .26
700 MHz .46 .21 .77 .38
935 MHz .37 .21 .55 .33
1300 MHz - .47 1.73 -
1500 MHz - .52 2.08 -
1650 MHz - 1.31 4.71 -
1993 Yupiteru MVT-7100 Review by Howard Bornstein.
Yupiteru MVT-7100 instruction manual.