16-10-2012, 10:21 AM
Glad to see you rate the HRO David, like you say ahead of it's time, max performance with min components, the AR88 was and is still an excellent receiver, the downside for me apart from the wieght is the tuning drive, switched selectivity (not variable) and no Xtal phasing control and the "s" meter arrangement.
The SX28 has switched selectivity and a Xtal phasing control and just about everything else including the Lamb based noise limiter.
The HRO has fully variable selectivity plus phasing control which is a bonus when trying to sought out SSB reception.
The attributes of the tuning drive on the HRO are well known with excellent resolution if the coil packs are set to bandspread mode, no backlash, no slipage and first class resetability, no noise limiter though until later on.
I think the AR88 was one of the first to use the then new fangled low loss polystyrene coil formers in the RF stages.
Prior to the AR88, the HRO had adopted the use of R39 Bakelite in the 30's which used crushed mica as a filler as opposed to wood flour which was hygroscopic, the new material giving a better Q figure, I think the R39 material was patented by Boonton? one of the best Q meter manufacturers around back then.The HRO's "S" meter used a bridge arrangement but with a "live" pot shaft! Also the IF's were capacitor tuned, and therefore also "live" no jammed or broken cores there.
These are only a few of the classic comms sets that were around at the time, there were many more. I believe some of the early Hammarlunds were very good although I have never owned an early one to try out.
In the more modern valve stakes the consensus seems to be the Collins 390A versus the Racal RA17/117, I always wanted the 390A but so far it eludes me, I hear the performance and engineering is 1st rate.
Lawrence.
The SX28 has switched selectivity and a Xtal phasing control and just about everything else including the Lamb based noise limiter.
The HRO has fully variable selectivity plus phasing control which is a bonus when trying to sought out SSB reception.
The attributes of the tuning drive on the HRO are well known with excellent resolution if the coil packs are set to bandspread mode, no backlash, no slipage and first class resetability, no noise limiter though until later on.
I think the AR88 was one of the first to use the then new fangled low loss polystyrene coil formers in the RF stages.
Prior to the AR88, the HRO had adopted the use of R39 Bakelite in the 30's which used crushed mica as a filler as opposed to wood flour which was hygroscopic, the new material giving a better Q figure, I think the R39 material was patented by Boonton? one of the best Q meter manufacturers around back then.The HRO's "S" meter used a bridge arrangement but with a "live" pot shaft! Also the IF's were capacitor tuned, and therefore also "live" no jammed or broken cores there.
These are only a few of the classic comms sets that were around at the time, there were many more. I believe some of the early Hammarlunds were very good although I have never owned an early one to try out.
In the more modern valve stakes the consensus seems to be the Collins 390A versus the Racal RA17/117, I always wanted the 390A but so far it eludes me, I hear the performance and engineering is 1st rate.
Lawrence.
