N8YX
04-21-2012, 08:55 AM
After a protracted period of time spent messing around with a TS-940S/R-71A and IC-751A/R-71A arrangement in the SO2R spot I decided to haul the vintage stuff out of storage and give it another go.
This morning finds 2x TR7/R7/RV75/SP75/CW75/MN2700s in the lineup. The R7s still drift a bit...and an N4YG DDS VFO kit in each should fix that.
Two of my R7s came from FCC field offices and as such were outfitted with some non-standard features: BNC Antenna Input and 3rd IF (50KHz) Output connectors. A consumer-model R7 doesn't have a way to get at the IF for monitoring purposes.
Why do I like these rigs so much? In a word: Configurability. Particularly where the IF filters are concerned. If one tallies up all of the filters - both OEM and aftermarket - which were offered for the 7 line (and the later TR5), the selection is rather impressive:
8/6/4/3/2.8/2.3/1.8/1.0/0.5/0.4/0.3 KHz B/W.
The cool thing is that ANY of those filters may be installed in any filter slot in the radios. Drake cautions against using other than the stock 2.3KHz B/W filter in the "default" transmit-enabled slot but many folks have used the 2.8 or 3.0KHz versions with great success. Radio Botswana went so far as to equip their TR7s with 4KHz filters in the TX position for use as enhanced-fidelity, remote news feeds...and they worked well in that role.
I'm looking to set one of my ex-FCC receivers up with 8 (or 6), 4, 2.3, 1.8 and 1.0KHz filters when I add the DDS unit; its companion TR7 will be equipped with a 4, 3.0 (or 2.8 ), 2.3 and 1.8KHz complement. This station will primarily be used for AM/SSB amateur/SWL/Ute work. The R7 in question has an AUX7 board fitted that's configured with programming modules for all of the popular SWBC bands, while the TR7 has an AUX7 with WARC band modules and a couple RX-only ranges installed.
The CW/FSK-position twins will have the following installed: (R7) 2.3/1.8/1.0/0.5/0.3KHz B/W; (TR7) 2.3/1.8/0.5/0.3KHz B/W.
Try that with any other rig short of a DDS-equipped unit...and even then you're into the K3/Orion/7800 tier.
Carlo, if you're reading this:
The TR7 we discussed is on the bench at the moment. I discovered a flaky capacitor in the AF Output circuit and am going to replace it...
This morning finds 2x TR7/R7/RV75/SP75/CW75/MN2700s in the lineup. The R7s still drift a bit...and an N4YG DDS VFO kit in each should fix that.
Two of my R7s came from FCC field offices and as such were outfitted with some non-standard features: BNC Antenna Input and 3rd IF (50KHz) Output connectors. A consumer-model R7 doesn't have a way to get at the IF for monitoring purposes.
Why do I like these rigs so much? In a word: Configurability. Particularly where the IF filters are concerned. If one tallies up all of the filters - both OEM and aftermarket - which were offered for the 7 line (and the later TR5), the selection is rather impressive:
8/6/4/3/2.8/2.3/1.8/1.0/0.5/0.4/0.3 KHz B/W.
The cool thing is that ANY of those filters may be installed in any filter slot in the radios. Drake cautions against using other than the stock 2.3KHz B/W filter in the "default" transmit-enabled slot but many folks have used the 2.8 or 3.0KHz versions with great success. Radio Botswana went so far as to equip their TR7s with 4KHz filters in the TX position for use as enhanced-fidelity, remote news feeds...and they worked well in that role.
I'm looking to set one of my ex-FCC receivers up with 8 (or 6), 4, 2.3, 1.8 and 1.0KHz filters when I add the DDS unit; its companion TR7 will be equipped with a 4, 3.0 (or 2.8 ), 2.3 and 1.8KHz complement. This station will primarily be used for AM/SSB amateur/SWL/Ute work. The R7 in question has an AUX7 board fitted that's configured with programming modules for all of the popular SWBC bands, while the TR7 has an AUX7 with WARC band modules and a couple RX-only ranges installed.
The CW/FSK-position twins will have the following installed: (R7) 2.3/1.8/1.0/0.5/0.3KHz B/W; (TR7) 2.3/1.8/0.5/0.3KHz B/W.
Try that with any other rig short of a DDS-equipped unit...and even then you're into the K3/Orion/7800 tier.
Carlo, if you're reading this:
The TR7 we discussed is on the bench at the moment. I discovered a flaky capacitor in the AF Output circuit and am going to replace it...